BMW 3- & 5-Series Service and Repair Manual E28 E30 E34... · by this manual) was introduced....

BMW 3- & 5-SeriesService and Repair ManualA K Legg LAE MIMI and Larry WarrenModels covered3-Series (E30)316 (83 to 88), 316i (88 to 91), 318i (83 to 91), 320i (87 to 91), 325i (87 to 91). Also Touring and Convertible versions of these models

5-Series (E28)518 (81 to 85), 518i (85 to 88), 525i (81 to 88), 528i (81 to 88), 535i (85 to 88), M535i (85 to 88)

5-Series (E34)518i (90 to 91), 520i (88 to 91), 525i (88 to 91), 530i (88 to 91), 535i (88 to 91)

Engines covered1596 cc, 1766 cc, 1795 cc, 1990 cc, 2494 cc, 2788 cc, 2986 cc & 3430 cc

Does not cover Diesel, dohc or V8 engines, or four-wheel-drive models

© Haynes Publishing 1997

A book in the Haynes Service and Repair Manual Series

All rights reserved. No part of this book may be reproduced or transmittedin any form or by any means, electronic or mechanical, includingphotocopying, recording or by any information storage or retrieval system,without permission in writing from the copyright holder.

ISBN 1 85960 236 3

British Library Cataloguing in Publication DataA catalogue record for this book is available from the British Library.

Printed by J H Haynes & Co. Ltd, Sparkford, Nr Yeovil,Somerset BA22 7JJ, England

Haynes PublishingSparkford, Nr Yeovil, Somerset BA22 7JJ, England

Haynes North America, Inc861 Lawrence Drive, Newbury Park, California 91320, USA

Editions Haynes S.A.147/149, rue Saint Honoré, 75001 PARIS, France

Haynes Publishing Nordiska ABBox 1504, 751 45 Uppsala, Sweden

(1948-256-11AA3)

ABCDEFGHIJKLMNOPQRST1 2 3

LIVING WITH YOUR BMWIntroduction Page 0•4

Safety First! Page 0•6

Anti-theft audio system Page 0•7

Instrument panel language display Page 0•7

Roadside RepairsJacking, towing and wheel changing Page 0•8

Jump starting Page 0•9

Identifying leaks Page 0•10

ROUTINE MAINTENANCERoutine Maintenance and Servicing Page 1•1

Lubricants and fluids Page 1•3

Maintenance schedule Page 1•4

Weekly checks Page 1•7

Every 6000 miles Page 1•11

Every 12 000 miles Page 1•16



Contents

REPAIRS & OVERHAULEngine and Associated SystemsIn-car engine repair procedures Page 2A•1

General engine overhaul procedures Page 2B•1

Cooling, heating and air conditioning systems •1

Fuel and exhaust systems Page 4•1

Engine electrical systems Page 5•1

Engine management and emission control systems Page 6•1

TransmissionManual transmission Page 7A•1

Automatic transmission Page 7B•1

Clutch and driveline Page 8•1

Brakes Braking system Page 9•1

Suspension Suspension and steering systems Page 10•1

Body Equipment Bodywork and fittings Page 11•1

ElectricalBody electrical systems Page 12•1

Wiring Diagrams Page 12•10

REFERENCEMOT Test Checks

Checks carried out from the driver’s seat Page REF•1

Checks carried out with the vehicle on the ground Page REF•2

Checks carried out with the vehicle raised Page REF•3

Checks carried out on your vehicle’s exhaust emission system Page REF•4

Tools and Working Facilities Page REF•5

General Repair Procedures Page REF•8

Fault Finding Page REF•9

Conversion factors Page REF•17

Automotive chemicals and lubricants Page REF•18

Buying spare parts and vehicle identification numbers Page REF•19

Glossary of Technical Terms Page REF•20

Index Page REF•25

Contents

0•4 Introduction

The E30 3-Series range first becameavailable in the UK in March 1983, andcontinued in production until April 1991, whenthe revised E36 3-Series range (not coveredby this manual) was introduced. Convertibleand Touring (Estate) models were introducedfor 1988, and these models have continued inE30 form to date.

The E28 5-Series models were introducedin October 1981, and were superseded inJune 1988 by the revised E34 5-Series range,Touring versions of which became availablefrom March 1992. Throughout this manual,E28 models are also referred to as “old-shape”, while E34 models are designated“new-shape”.

The models covered by this manual areequipped with single overhead cam in-linefour- and six-cylinder engines. Early 316 and518 models are fitted with carburettors, but allother models are fitted with fuel injectionsystems. Transmissions are a five-speedmanual, or three- or four-speed automatic.The transmission is mounted to the back ofthe engine, and power is transmitted to thefully-independent rear axle through a two-piece propeller shaft. The final drive unit isbolted solidly to a frame crossmember, anddrives the rear wheels through driveshafts

equipped with inner and outer constantvelocity joints.

The front suspension is of MacPhersonstrut type, with the coil spring/shock absorberunit making up the upper suspension link. Therear suspension is made up of coil spring-over-shock absorber struts, or coil springsand conventional shock absorbers,depending on model.

The brakes are disc type at the front, witheither drums or discs at the rear, dependingon model. Servo assistance is standard on allmodels. Some later models are equipped withan Anti-lock Braking System (ABS).

All models are manufactured to fine limits,and live up to the BMW reputation of qualityworkmanship. Although many of the modelscovered by this manual appear complex atfirst sight, they should present no problems tothe home mechanic.

Note for UK readersThe greater part of this manual was

originally written in the USA. Some of thephotographs used are of American-marketmodels, but the procedures given are fullyapplicable to right-hand-drive models (or havebeen amended where necessary).

AcknowledgementsThanks are due to Champion Spark Plug,

who supplied the illustrations showing sparkplug conditions. Thanks are also due toSykes-Pickavant Limited, who provided someof the workshop tools, and to all those peopleat Sparkford who helped in the production ofthis manual. Technical writers whocontributed to this project include RobertMaddox, Mark Ryan and Mike Stubblefield.

We take great pride in the accuracy ofinformation given in this manual, butvehicle manufacturers make alterationsand design changes during the productionrun of a particular vehicle of which they donot inform us. No liability can be acceptedby the authors or publishers for loss,damage or injury caused by any errors in, or omissions from, theinformation given.

Project vehiclesThe main project vehicle used in the

preparation of this manual for the UK marketwas a 1988 BMW 318i with an M40/B18engine.

Introduction to the BMW 3- and 5-Series

BMW 320i Saloon (E30)

0•5Introduction

BMW 518i (E28)

BMW 325i Touring (E30)

BMW 535i (E34)

BMW 325i Convertible (E30)

0•6 Safety First!

Working on your car can be dangerous.This page shows just some of the potentialrisks and hazards, with the aim of creating asafety-conscious attitude.

General hazardsScalding• Don’t remove the radiator or expansiontank cap while the engine is hot.• Engine oil, automatic transmission fluid orpower steering fluid may also be dangerouslyhot if the engine has recently been running.

Burning• Beware of burns from the exhaust systemand from any part of the engine. Brake discsand drums can also be extremely hotimmediately after use.

Crushing• When working under or neara raised vehicle,alwayssupplement thejack with axlestands, or usedrive-onramps.Neverventureunder a car whichis only supported by a jack.• Take care if loosening or tightening high-torque nuts when the vehicle is on stands.Initial loosening and final tightening shouldbe done with the wheels on the ground.

Fire• Fuel is highly flammable; fuel vapour isexplosive. • Don’t let fuel spill onto a hot engine. • Do not smoke or allow naked lights(including pilot lights) anywhere near avehicle being worked on. Also beware ofcreating sparks (electrically or by use of tools).• Fuel vapour is heavier than air, so don’twork on the fuel system with the vehicle overan inspection pit.• Another cause of fire is an electricaloverload or short-circuit. Take care whenrepairing or modifying the vehicle wiring.• Keep a fire extinguisher handy, of a typesuitable for use on fuel and electrical fires.

Electric shock • Ignition HTvoltage can bedangerous,especially topeople with heartproblems or apacemaker. Don’twork on or near theignition system withthe engine running orthe ignition switched on.

• Mains voltage is also dangerous. Makesure that any mains-operated equipment iscorrectly earthed. Mains power points shouldbe protected by a residual current device(RCD) circuit breaker.

Fume or gas intoxication • Exhaust fumes arepoisonous; they oftencontain carbonmonoxide, which israpidly fatal if inhaled.Never run theengine in aconfined spacesuch as a garagewith the doors shut.• Fuel vapour is alsopoisonous, as are the vapours from somecleaning solvents and paint thinners.

Poisonous or irritant substances• Avoid skin contact with battery acid andwith any fuel, fluid or lubricant, especiallyantifreeze, brake hydraulic fluid and Dieselfuel. Don’t syphon them by mouth. If such asubstance is swallowed or gets into the eyes,seek medical advice.• Prolonged contact with used engine oil cancause skin cancer. Wear gloves or use abarrier cream if necessary. Change out of oil-soaked clothes and do not keep oily rags inyour pocket.• Air conditioning refrigerant forms apoisonous gas if exposed to a naked flame(including a cigarette). It can also cause skinburns on contact.

Asbestos• Asbestos dust can cause cancer if inhaledor swallowed. Asbestos may be found ingaskets and in brake and clutch linings.When dealing with such components it issafest to assume that they contain asbestos.

Special hazardsHydrofluoric acid• This extremely corrosive acid is formedwhen certain types of synthetic rubber, foundin some O-rings, oil seals, fuel hoses etc, areexposed to temperatures above 4000C. Therubber changes into a charred or stickysubstance containing the acid. Once formed,the acid remains dangerous for years. If itgets onto the skin, it may be necessary toamputate the limb concerned.• When dealing with a vehicle which hassuffered a fire, or with components salvagedfrom such a vehicle, wear protective glovesand discard them after use.

The battery• Batteries contain sulphuric acid, whichattacks clothing, eyes and skin. Take carewhen topping-up or carrying the battery.• The hydrogen gas given off by the batteryis highly explosive. Never cause a spark orallow a naked light nearby. Be careful whenconnecting and disconnecting batterychargers or jump leads.

Air bags• Air bags can cause injury if they go offaccidentally. Take care when removing thesteering wheel and/or facia. Special storageinstructions may apply.

Diesel injection equipment• Diesel injection pumps supply fuel at veryhigh pressure. Take care when working onthe fuel injectors and fuel pipes.

Warning: Never expose the hands,face or any other part of the bodyto injector spray; the fuel can

penetrate the skin with potentially fatalresults.

Remember...DO• Do use eye protection when using powertools, and when working under the vehicle.

• Do wear gloves or use barrier cream toprotect your hands when necessary.

• Do get someone to check periodicallythat all is well when working alone on thevehicle.

• Do keep loose clothing and long hair wellout of the way of moving mechanical parts.

• Do remove rings, wristwatch etc, beforeworking on the vehicle – especially theelectrical system.

• Do ensure that any lifting or jackingequipment has a safe working load ratingadequate for the job.

A few tipsDON’T• Don’t attempt to lift a heavy componentwhich may be beyond your capability – getassistance.

• Don’t rush to finish a job, or takeunverified short cuts.

• Don’t use ill-fitting tools which may slipand cause injury.

• Don’t leave tools or parts lying aroundwhere someone can trip over them. Mopup oil and fuel spills at once.

• Don’t allow children or pets to play in ornear a vehicle being worked on.

0•7Anti-theft audio system

Anti-theft audio systemGeneral information

Some models are equipped with an audiosystem having an anti-theft feature that willrender the stereo inoperative if stolen. If thepower source to the stereo is cut, the stereowon’t work even if the power source isimmediately re-connected. If your vehicle isequipped with this anti-theft system, do notdisconnect the battery or remove the stereounless you have the individual code numberfor the stereo.

Refer to the owner’s handbook supplied

with the vehicle for more completeinformation on this audio system and its anti-theft feature.

Unlocking procedure1 Turn on the radio. The word “CODE” shouldappear on the display.2 Using the station preset selector buttons,enter the five-digit code. If you make amistake when entering the code, continuethe five-digit sequence anyway. If you heara “beep,” however, stop immediately and

start the sequence over again. Note: Youhave three attempts to enter the correctcode. If the correct code isn’t entered inthree tries, you’ll have to wait one hour, withthe radio on, before you enter the codesagain.5 Once the code has been entered correctly,the word “CODE” should disappear from thedisplay, and the radio should play (you’ll haveto tune-in and enter your preset stations,however).6 If you have lost your code number, contacta BMW dealer service department.

Instrument panel language displayOn some later models, disconnecting the

battery may cause the instrument paneldisplay to default to the German language(this does not usually apply to UK models). Ifit is necessary to reset the correct languageafter the battery is reconnected, proceed asfollows. With all the doors shut and the

ignition on (engine not running), press the tripreset button until the panel displays thedesired language. There are eight languagesavailable. If you wish to bypass a particularselection, release the reset button and pressagain - this will cause the display to advanceto the next language. Once the correct

language has been selected, continue holdingthe reset button until the display reads “I.O.Version 2.0”. Continue holding the button untilit reads “H.P. Version 3.4”, then release thebutton.

0•8 Roadside Repairs

Jacking and wheelchanging

The jack supplied with the vehicle shouldbe used only for raising the vehicle whenchanging a tyre or placing axle stands underthe frame.

Warning: Never crawl under thevehicle or start the engine whenthis jack is being used as theonly means of support.

When changing a wheel, the vehicle shouldbe on level ground, with the handbrake firmlyapplied, and the wheels chocked. Selectreverse gear (manual transmission) or Park(automatic transmission). Prise off the hubcap (if equipped) using the tapered end of thewheel brace. Loosen the wheel bolts half aturn, leaving them in place until the wheel israised off the ground.

Position the head of the jack under the sideof the vehicle, making sure it engages with the

pocket made for this purpose (just behind thefront wheel, or forward of the rear wheel).Engage the wheel brace handle and turn itclockwise until the wheel is raised off theground. Unscrew the bolts, remove the wheeland fit the spare.

Refit the wheel bolts and tighten themfinger-tight. Lower the vehicle by turning thewheel brace anti-clockwise. Remove the jackand tighten the bolts in a diagonal pattern tothe torque listed in the Chapter 1Specifications. If a torque wrench is notavailable, have the torque checked by a BMWdealer or tyre fitting specialist as soon aspossible. Refit the hubcap.

TowingVehicles with manual transmission can be

towed with all four wheels on the ground, ifnecessary. Automatic transmission-equippedvehicles can only be towed with all four

wheels on the ground providing that thespeed does not exceed 35 mph and thedistance is not over 50 miles, otherwisetransmission damage can result. Forpreference, regardless of transmission type,the vehicle should be towed with the driven(rear) wheels off the ground.

Proper towing equipment, specificallydesigned for the purpose, should be used,and should be attached to the main structuralmembers of the vehicle, not to the bumpers orbumper brackets. Sling-type towingequipment must not be used on thesevehicles.

Safety is a major consideration whiletowing. The handbrake should be released,and the transmission should be in neutral. Thesteering must be unlocked (ignition switchturned to position “1”). Remember thatpower-assisted steering (where fitted) and thebrake servo will not work with the engineswitched off.

Jacking, towing and wheel changing

0•9Roadside Repairs

When jump-starting a car using abooster battery, observe the followingprecautions:

4 Before connecting the boosterbattery, make sure that the ignition isswitched off.

4 Ensure that all electrical equipment(lights, heater, wipers, etc) isswitched off.

4 Make sure that the booster battery isthe same voltage as the dischargedone in the vehicle.

4 If the battery is being jump-startedfrom the battery in another vehicle,the two vehcles MUST NOT TOUCHeach other.

4 Make sure that the transmission is inneutral (or PARK, in the case ofautomatic transmission).

Jump starting will get you outof trouble, but you must correctwhatever made the battery goflat in the first place. There are three possibilities:

1 The battery has been drained byrepeated attempts to start, or by

leaving the lights on.

2 The charging system is not workingproperly (alternator drivebelt slack

or broken, alternator wiring fault oralternator itself faulty).

3 The battery itself is at fault(electrolyte low, or battery worn out).

Connect one end of the red jump lead tothe positive (+) terminal of the flatbattery

Connect the other end of the red lead tothe positive (+) terminal of the boosterbattery.

Connect one end of the black jump leadto the negative (-) terminal of thebooster battery

Connect the other end of the blackjump lead to a bolt or bracket on theengine block, well away from thebattery, on the vehicle to be started.

1 2 3

4

Make sure that the jump leads will notcome into contact with the fan, drive-belts or other moving parts of theengine.

5

Start the engine using the boosterbattery, then with the engine running atidle speed, disconnect the jump leads inthe reverse order of connection.

6

Jump starting

0•10 Roadside Repairs

Puddles on the garage floor or drive, orobvious wetness under the bonnet or underneath the car, suggest a leak that needsinvestigating. It can sometimes be difficult todecide where the leak is coming from,especially if the engine bay is very dirtyalready. Leaking oil or fluid can also be blownrearwards by the passage of air under the car,giving a false impression of where theproblem lies.

Warning: Most automotive oilsand fluids are poisonous. Washthem off skin, and change out ofcontaminated clothing, withoutdelay.

Identifying leaksThe smell of a fluid leakingfrom the car may provide aclue to what’s leaking. Somefluids are distinctively

coloured. It may help to clean the carcarefully and to park it over some cleanpaper overnight as an aid to locating thesource of the leak.Remember that some leaks may onlyoccur while the engine is running.

Sump oil Gearbox oil

Brake fluid Power steering fluid

Oil from filter

Antifreeze

Engine oil may leak from the drain plug... ...or from the base of the oil filter.

Leaking antifreeze often leaves a crystallinedeposit like this.

Gearbox oil can leak from the seals at theinboard ends of the driveshafts.

A leak occurring at a wheel is almostcertainly brake fluid.

Power steering fluid may leak from the pipeconnectors on the steering rack.

1

EngineOil filter

M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C121M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C160M30 engines

3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C1605-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X115

M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X120Valve clearances (intake and exhaust)

M10 enginesCold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 mmHot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm



M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic adjusters

Cooling systemAntifreeze mixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40% antifreeze/60% water

Chapter 1Routine maintenance and servicing

Air filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Automatic transmission fluid and filter change . . . . . . . . . . . . . . . . . 28Automatic transmission fluid level check . . . . . . . . . . . . . . . . . . . . . 8Battery check, maintenance and charging . . . . . . . . . . . . . . . . . . . . 13 Brake system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Cooling system - draining, flushing and refilling . . . . . . . . . . . . . . . . 29Cooling system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Differential lubricant change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Differential lubricant level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Driveshaft gaiter check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Drivebelt check, adjustment and renewal . . . . . . . . . . . . . . . . . . . . . 11Engine idle speed and CO level check and adjustment . . . . . . . . . . 12Engine oil and filter change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Engine timing belt renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Evaporative Emissions Control (EVAP) system check . . . . . . . . . . . 33Fluid level checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Fuel system check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Manual transmission lubricant change . . . . . . . . . . . . . . . . . . . . . . . 31Manual transmission lubricant level check . . . . . . . . . . . . . . . . . . . . 16Power steering fluid level check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Routine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Service light resetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Spark plug check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Spark plug HT leads, distributor cap and rotor - check

and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Steering and suspension check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Throttle linkage - check and lubrication . . . . . . . . . . . . . . . . . . . . . . 19Tyre and tyre pressure checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Tyre rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Tune-up general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Underbonnet hoses - check and renewal . . . . . . . . . . . . . . . . . . . . . 10Valve clearances - check and adjustment . . . . . . . . . . . . . . . . . . . . 18Wiper blades - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1•1

Easy, suitable fornovice with littleexperience

Fairly easy, suitablefor beginner withsome experience

Fairly difficult,suitable for competentDIY mechanic

Difficult, suitable forexperienced DIYmechanic

Very difficult,suitable for expertDIY or professional

Degrees of difficulty

Specifications

Contents

Fuel systemIdle speed

3-Series, E30316 with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 ± 50 rpm316i with M40/B16 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 ± 40 rpm318i with M10/B18 engine (manual transmission) . . . . . . . . . . . . . 850 ± 50 rpm318i with M10/B18 engine (automatic transmission) . . . . . . . . . . . 750 ± 50 rpm318i with M40/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 ± 40 rpm320i with M20/B20 engine (L-Jetronic) . . . . . . . . . . . . . . . . . . . . . . 800 ± 50 rpm320i with M20/B20 engine (Motronic) . . . . . . . . . . . . . . . . . . . . . . . 760 ± 40 rpm325i with M20/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760 ± 40 rpm

5-Series, E28 (“old-shape”)518 and 518i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . 800 ± 50 rpmAll other models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 ± 50 rpm

5-Series, E34 (“new-shape”)518i with M40/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 ± 40 rpm520i with M20/B20M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760 ± 40 rpm525i with M20/B25M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760 ± 40 rpm530i with M30/B30M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 ± 50 rpm535i with M30/B35M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 ± 50 rpm

CO% at 3000 rpm3-Series, E30

316 with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 to 1.0316i and 318i with M40/B16 engine . . . . . . . . . . . . . . . . . . . . . . . . 0.7 ± 0.5318i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 maximum320i with M20/B20 engine (L-Jetronic) . . . . . . . . . . . . . . . . . . . . . . 1.0 ± 0.5320i with M20/B20 engine (Motronic) . . . . . . . . . . . . . . . . . . . . . . . 0.7 ± 0.5325i with M20/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 ± 0.5

5-Series, E28 (“old-shape”)518 and 518i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . 1.0 maximum525i with M30/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 ± 0.5528i with M30/B28 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 maximum535i with M30/B34 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 to 1.5M535i with M30/B34 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 to 1.5

5-Series, E34 (“new-shape”)All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.7 ± 0.5

Air filter elementM10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion W155 (round) or U504 (square)M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion U504 or U527M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion U504 or U527M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion U527

Fuel filter (all fuel injection engines) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion L206

Ignition systemSpark plug type

M10, M20 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion N9YCCM40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C9YCC

Spark plug gap* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 mmSpark plug (HT) leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion type not available* The spark plug gap quoted is that recommended by Champion for their specified plugs listed above. If spark plugs of any other type are to befitted, refer to their manufacturer’s spark plug gap recommendations.

Brakes Disc brake pad thickness (minimum) . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 mmDrum brake shoe lining thickness (minimum) . . . . . . . . . . . . . . . . . . . . . 2.0 mm

Wiper bladesWindscreen

3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X-51033-Series passenger side from 1991 . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X-5103 (20 inch) or Champion X-5303 (21 inch)5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X-45035-Series, E34 (“new-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion type not available

Tailgate3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion X-45035-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion type not available

1•2 Servicing Specifications

Tyre pressures (cold) - bars (psi) Front Rear3-Series, E30

316 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 (28) 2.1 (30)316i

Saloon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.1 (30)Estate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.2 (32)

318i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 (26) 1.9 (28)320i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 (28) 2.0 (29)325i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.3 (33)

5-Series, E28 (“old-shape”)518 and 518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.0 (29)525i and 528i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.2 (32)535i and M535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 (33) 2.5 (36)

5-Series, E34 (“new-shape”)518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.0 (29)520i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 (32) 2.1 (30)525i, 530i and 535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 (29) 2.3 (33)

Torque wrench settings NmAutomatic transmission sump bolts

Three-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 to 9Four-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 to 7

Spark plugsM10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 30Except M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 33

Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 33Wheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Lubricants and fluidsComponent or system Lubricant type/specification

Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multigrade engine oil, viscositySAE 10W/40 to 20W/50, to API SG

Cooling system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ethylene glycol-based antifreeze with corrosion inhibitors

Manual transmission* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gear oil, viscosity SAE 80 to API-GL4, or single-grade mineral-basedengine oil, viscosity SAE 20, 30 or 40 to API-SG

Automatic transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dexron ll type ATF

Final drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BMW-approved hypoid gear oil, viscosity SAE 90**

Brake and clutch hydraulic systems . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic brake fluid to SAE J 1703 or DOT 4

Power steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dexron ll type ATF* E34 520i & 525i with air conditioning, E34 530i & 535i - Dexron II type ATF)** Only available in bulk; refer to your BMW dealer

Capacities*

1•3

1

Engine oilM10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 litresM20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 litresM30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8 litresM40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 litres

Cooling systemM10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 litresM20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 litresM30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0 litresM40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 litres

Fuel tank3-Series, E30

Saloon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 litres (early), 64 litres (later)

Estate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 litres (early), 70 litres (later)

5-SeriesE28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . 70 litresE34 (“new-shape”) . . . . . . . . . . . . . . . . . . . . . . . 81 litres

Manual transmissionZF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 litresGetrag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 to 1.5 litres

Automatic transmission (refill)3-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 litres4-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 litres

Final drive capacity (drain and refill)3-Series, E30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.9 litres5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . 0.9 litres5-Series, E34 (“new-shape”) . . . . . . . . . . . . . . . . . 1.7 litres

*All capacities approximate

Servicing Specifications

Maintenance scheduleThe following maintenance intervals are based on the assumption

that the vehicle owner will be doing the maintenance or service work,as opposed to having a dealer service department do the work.Although the time/mileage intervals are loosely based on factory rec-ommendations, most have been shortened to ensure, for example, thatsuch items as lubricants and fluids are checked/changed at intervalsthat promote maximum engine/driveline service life. Also, subject tothe preference of the individual owner interested in keeping his or hervehicle in peak condition at all times, and with the vehicle’s ultimateresale in mind, many of the maintenance procedures may beperformed more often than recommended in the following schedule.We encourage such owner initiative.

When the vehicle is new, it should be serviced initially by a factory-authorised dealer service department, to protect the factory warranty.In many cases, the initial maintenance check is done at no cost to theowner (check with your dealer service department for moreinformation).

1•4 Maintenance and servicing

Every 250 miles or weekly, whichevercomes firstmm Check the engine oil level (Section 4) mm Check the engine coolant level (Section 4) mm Check the brake fluid level (Section 4)mm Check the clutch fluid level (Section 4)mm Check the washer fluid level (Section 4)mm Check the tyres and tyre pressures (Section 5)

Every 6000 miles or 6 months,whichever comes first All items listed above, plus:

mm Change the engine oil and oil filter (Section 6) mm Check the power steering fluid level (Section 7) mm Check the tyres, and rotate if necessary (Section 9)mm Check the automatic transmission fluid level

(Section 8) mm Check the underbonnet hoses (Section 10)mm Check/adjust the drivebelts (Section 11)mm Check engine idle speed and CO (Section 12)

Every 12 000 miles or 12 months,whichever comes first All items listed above, plus:

mm Check/service the battery (Section 13)mm Check the spark plugs (Section 14)mm Check/renew the HT leads, distributor cap and

rotor (Section 15)mm Check/top-up the manual transmission lubricant

(Section 16)mm Check the differential oil level (Section 17)mm Check the valve clearances, and adjust if

necessary - does not apply to M40 engines(Section 18)

mm Check and lubricate the throttle linkage (Section 19)mm Renew the air filter (Section 20)mm Check the fuel system (Section 21) mm Inspect the cooling system (Section 22) mm Inspect the exhaust system (Section 23) mm Inspect the steering and suspension components

(Section 24) mm Check the driveshaft gaiter(s) (Section 25)mm Inspect the brakes (Section 26)mm Inspect/renew the windscreen wiper blades

(Section 27)

Every 24 000 miles or 2 years,whichever comes first All items listed above plus:

mm Change the automatic transmission fluid and filter(Section 28)

mm Drain, flush and refill the cooling system (Section 29)mm Renew the spark plugs (Section 14)mm Check/renew the spark plug HT leads (Section 15)mm Renew the fuel filter (Section 30)mm Change the manual transmission lubricant (Section 31)mm Change the differential oil (Section 32)mm Check the evaporative emissions system, where

applicable (Section 33) mm Reset the service indicator lights (Section 34)mm Renew brake fluid by bleeding (see Chapter 9)mm Check the handbrake operation (see Chapter 9)

Every 60 000 milesmm Renew the timing belt (Section 35)

1•5

Underbonnet view (left-hand side) of a UK model 318i (1988)

1 Radiator2 Intake manifold3 Idle control valve4 Accelerator cable5 Diagnostic/service indicator resetting

socket6 Fuse/relay box7 Brake hydraulic fluid reservoir8 Airflow meter9 Air cleaner unit

10 Radiator filler cap11 Radiator top hose12 Oil filter housing

Underbonnet view (right-hand side) of aUK model 318i (1988)

1 Oil filler cap2 Valve cover3 Engine oil filler dipstick4 Viscous cooling fan5 Distributor cap cover6 Bottom hose7 Windscreen washer fluid reservoir8 Ignition coil9 Clutch hydraulic fluid reservoir

10 Battery

1

Maintenance and Servicing

1•6 Maintenance and Servicing

Front underbody view of a UK model 318i(1988)

1 Radiator2 Engine oil drain plug3 Front suspension control arm (left-hand

side)4 Front anti-roll bar5 Clutch slave cylinder6 Transmission7 Exhaust downpipe8 Front suspension control arm (right-hand

side)

Typical rear underside components

1 Exhaust system2 Differential fill/check plug3 Driveshaft boot4 Fuel tank filler tube5 Differential drain plug6 Rear brake7 Rear shock absorber

1 Introduction

This Chapter is designed to help the homemechanic maintain his or her vehicle with thegoals of maximum performance, economy,safety and reliability in mind. Included is amaster maintenance schedule, followed byprocedures dealing specifically with each itemon the schedule. Visual checks, adjustments,component renewal and other helpful itemsare included. Refer to the accompanyingillustrations of the engine compartment andthe underside of the vehicle for the locationsof various components. Servicing the vehicle,in accordance with the mileage/timemaintenance schedule and the step-by-stepprocedures, will result in a plannedmaintenance programme that should producea long and reliable service life. Keep in mindthat it is a comprehensive plan, so maintainingsome items but not others at specifiedintervals, will not produce the same results.

2 Routine maintenance

As you service the vehicle, you will discoverthat many of the procedures can - and shouldbe grouped together, because of the natureof the particular procedure you’re performing,or because of the close proximity of twootherwise-unrelated components to oneanother. For example, if the vehicle is raisedfor chassis lubrication, you should inspect theexhaust, suspension, steering and fuel

systems while you’re under the vehicle. Whenthe wheels are removed for other work, itmakes good sense to check the brakes, sincethe wheels are already removed. Finally, let’ssuppose you have to borrow a torque wrench.Even if you only need it to tighten the sparkplugs, you might as well check the torque ofas many critical nuts and bolts as time allows.

The first step in this maintenanceprogramme is to prepare yourself before theactual work begins. Read through all theprocedures you’re planning to do, then gatherup all the parts and tools needed. If it lookslike you might run into problems during aparticular job, seek advice from a mechanic oran experienced do-it-yourselfer.

3 Engine “tune-up” - general information

The term “tune-up” is used in this manual torepresent a combination of individualoperations rather than one specific procedure.

If, from the time the vehicle is new, theroutine maintenance schedule is followedclosely, and frequent checks are made of fluidlevels and high-wear items, as suggestedthroughout this manual, the engine will bekept in relatively good running condition, andthe need for additional work will be minimised.

More likely than not, however, there will betimes when the engine is running poorly dueto a lack of regular maintenance. This is evenmore likely if a used vehicle, which has notreceived regular and frequent maintenancechecks, is purchased. In such cases, anengine tune-up will be needed outside of theregular maintenance intervals.

The first step in any tune-up or diagnosticprocedure to help correct a poor-runningengine is a cylinder compression check. Acompression check (see Chapter 2B) will helpdetermine the condition of internal enginecomponents, and should be used as a guidefor tune-up and repair procedures. If, forinstance, a compression check indicatesserious internal engine wear, a conventionaltune-up will not improve the performance ofthe engine, and would be a waste of time andmoney. Because of its importance, thecompression check should be done bysomeone with the right equipment, and theknowledge to use it properly.

The following procedures are those mostoften needed to bring a generally poor-running engine back into a proper state oftune.

Minor tune-upCheck all engine-related fluids (Section 4)Check all underbonnet hoses (Section 10)Check and adjust the drivebelts (Sec-tion 11)Clean, inspect and test the battery (Sec-tion 13)Renew the spark plugs (Section 14)Inspect the spark plug HT leads, distributorcap and rotor (Section 15)Check the air filter (Section 20)Check the cooling system (Section 22)

Major tune-upAll items listed under minor tune-up, plus . . .

Check the ignition system (see Chapter 5)Check the charging system (see Chapter 5)Check the fuel system (see Chapter 4)Renew the spark plug HT leads, distributorcap and rotor (Section 15)

1•7

1

Routine Maintenance

Weekly checks

4 Fluid level checks 1Note: The following are fluid level checks tobe done on a 250-mile or weekly basis.Additional fluid level checks can be found inspecific maintenance procedures whichfollow. Regardless of intervals, be alert to fluidleaks under the vehicle, which would indicatea fault to be corrected immediately.1 Fluids are an essential part of thelubrication, cooling, brake and windscreenwasher systems. Because the fluids graduallybecome depleted and/or contaminated duringnormal operation of the vehicle, they must beperiodically replenished. See “Lubricants andfluids” at the beginning of this Chapter beforeadding fluid to any of the followingcomponents. Note: The vehicle must be onlevel ground when any fluid levels arechecked.

Engine oil2 Engine oil is checked with a dipstick, whichis located on the side of the engine (refer tothe underbonnet illustrations in this Chapterfor dipstick location). The dipstick extendsthrough a metal tube down into the sump. 3 The engine oil should be checked beforethe vehicle has been driven, or at least 15 minutes after the engine has been shut off.

4 Pull the dipstick out of the tube, and wipeall of the oil away from the end with a cleanrag or paper towel. Insert the clean dipstick allthe way back into the tube, and pull it outagain. Note the oil at the end of the dipstick.At its highest point, the oil should be between

the two notches or marks (see illustration). 5 It takes one litre of oil to raise the level fromthe lower mark to the upper mark on thedipstick. Do not allow the level to drop belowthe lower mark, or oil starvation may cause

4.4 The oil level should be kept betweenthe two marks, preferably at or near theupper one - if it isn’t, add enough oil to

bring the level to the upper mark

If the oil is checkedimmediately after driving thevehicle, some of the oil willremain in the upper part of

the engine, resulting in an inaccuratereading on the dipstick.

engine damage. Conversely, overfilling theengine (adding oil above the upper mark) maycause oil-fouled spark plugs, oil leaks, or oilseal failures. 6 To add oil, remove the filler cap located onthe valve cover (see illustrations). Afteradding oil, wait a few minutes to allow thelevel to stabilise, then pull the dipstick out andcheck the level again. Add more oil if required.Refit the filler cap, tightening it by hand only. 7 Checking the oil level is an importantpreventive maintenance step. A consistentlylow oil level indicates oil leakage throughdamaged seals or defective gaskets, or oilburning (internal leakage past worn rings orvalve guides). The condition of the oil shouldalso be noted. If the oil looks milky in colour orhas water droplets in it, the cylinder headgasket may be blown, or the head or blockmay be cracked. The engine should berepaired immediately. Whenever you checkthe oil level, slide your thumb and index fingerup the dipstick before wiping off the oil. If yousee small dirt or metal particles clinging to thedipstick, the oil should be changed (seeSection 6).

Engine coolantWarning: Do not allow antifreezeto come in contact with yourskin, or with the vehicle

paintwork. Rinse off spills immediatelywith plenty of water. Antifreeze is highlytoxic if ingested. Never leave antifreezelying around in an open container, or inpuddles on the floor; children and pets areattracted by its sweet smell, and may drinkit. Check with local authorities aboutdisposing of used antifreeze. Localcollection centres may exist, to see thatantifreeze is disposed of safely. 8 All vehicles covered by this manual areequipped with a pressurised coolant recoverysystem. On most models, a white plasticexpansion tank (or coolant reservoir) locatedin the engine compartment is connected by ahose to the radiator. As the engine heats upduring operation, the expanding coolant fillsthe tank. As the engine cools, the coolant isautomatically drawn back into the coolingsystem, to maintain the correct level.9 The coolant level in the reservoir (seeillustrations) should be checked regularly.Add a 40%/60% mixture of ethylene glycol-based antifreeze to water (see illustration).

Warning: Do not remove theexpansion tank cap or radiatorcap to check the coolant level,unless the engine is completely

cold! The level in the reservoir varies withthe temperature of the engine. When theengine is cold, the coolant level should be

above the LOW mark on the reservoir.Once the engine has warmed up, the levelshould be at or near the FULL mark. If itisn’t, allow the engine to cool, then removethe cap from the reservoir. 10 Drive the vehicle and recheck the coolantlevel. If only a small amount of coolant isrequired to bring the system up to the properlevel, plain water can be used. However,repeated additions of water will dilute theantifreeze. In order to maintain the properratio of antifreeze and water, always top-upthe coolant level with the correct mixture.11 If the coolant level drops consistently,there must be a leak in the system. Inspectthe radiator, hoses, filler cap, drain plugs andwater pump (see Section 29). If no leaks arenoted, have the expansion tank cap orradiator cap pressure-tested by a BMWdealer.12 If you have to remove the cap, wait untilthe engine has cooled completely, then wrapa thick cloth around the cap and turn it to thefirst stop. If coolant or steam escapes, let theengine cool down longer, then remove thecap.13 Check the condition of the coolant aswell. It should be relatively clear. If it’s brownor rust-coloured, the system should bedrained, flushed and refilled. Even if thecoolant appears to be normal, the corrosion

1•8

4.9d Adding antifreeze mixture4.9c On some 5-Series models, theexpansion tank (coolant reservoir) is

located on the bulkhead

4.9b On other models, the expansion tank(coolant reservoir) is located on the side ofthe engine compartment - remove the cap

to add coolant

4.9a On some models, the expansion tank(coolant reservoir) is mounted on the

radiator - make sure the level is kept at ornear the FULL mark (arrowed)

4.6b Topping-up the engine oil4.6a The threaded oil filler cap is locatedin the valve cover - always make sure thearea around the opening is clean before

unscrewing the cap

Weekly Checks

inhibitors wear out, so it must be renewed atthe specified intervals.

Brake and clutch fluidWarning: Brake fluid can harmyour eyes and damage paintedsurfaces, so use extreme cautionwhen handling or pouring it. Do

not use brake fluid that has been standingopen or is more than one year old. Brakefluid absorbs moisture from the air, whichcan cause a dangerous loss of brakeeffectiveness. Use only the specified typeof brake fluid. Mixing different types (suchas DOT 3 or 4 and DOT 5) can cause brakefailure. 14 The brake master cylinder is mounted atthe left rear corner of the enginecompartment. The clutch fluid reservoir(manual transmission models) is mounted onthe right-hand side.15 To check the clutch fluid level, observethe level through the translucent reservoir.The level should be at or near the stepmoulded into the reservoir. If the level is low,remove the reservoir cap to add the specifiedfluid (see illustration).16 The brake fluid level is checked by lookingthrough the plastic reservoir mounted on themaster cylinder (see illustration). The fluidlevel should be between the MAX and MINlines on the reservoir. If the fluid level is low,first wipe the top of the reservoir and the capwith a clean rag, to prevent contamination ofthe system as the cap is unscrewed. Top-upwith the recommended brake fluid, but do notoverfill. 17 While the reservoir cap is off, check themaster cylinder reservoir for contamination. Ifrust deposits, dirt particles or water dropletsare present, the system should be drainedand refilled.18 After filling the reservoir to the properlevel, make sure the cap is seated correctly, toprevent fluid leakage and/or contamination. 19 The fluid level in the master cylinder willdrop slightly as the disc brake pads wear.There is no need to top up to compensate forthis fall provided that the level stays above theMIN line; the level will rise again when newpads are fitted. A very low level may indicate

worn brake pads. Check for wear (see Sec-tion 26).20 If the brake fluid level drops consistently,check the entire system for leaks immediately.Examine all brake lines, hoses andconnections, along with the calipers, wheelcylinders and master cylinder (see Sec-tion 26). 21 When checking the fluid level, if youdiscover one or both reservoirs empty ornearly empty, the brake or clutch hydraulicsystem should be checked for leaks and bled(see Chapters 8 and 9).

Windscreen washer fluid22 Fluid for the windscreen washer system isstored in a plastic reservoir in the enginecompartment (see illustration).23 In milder climates, plain water can beused in the reservoir, but it should be kept nomore than two-thirds full, to allow forexpansion if the water freezes. In colderclimates, use windscreen washer systemantifreeze, available at any car accessoryshop, to lower the freezing point of the fluid.This comes in concentrated or pre-mixedform. If you purchase concentrated antifreeze,mix the antifreeze with water in accordancewith the manufacturer’s directions on thecontainer.

Caution: Do not use coolingsystem antifreeze - it will damagethe vehicle’s paint.

5 Tyre and tyre pressurechecks 1

1 Periodic inspection of the tyres may saveyou the inconvenience of being stranded witha flat tyre. It can also provide you with vitalinformation regarding possible problems inthe steering and suspension systems beforemajor damage occurs. 2 Tyres are equipped with bands that willappear when tread depth reaches 1.6 mm, atwhich time the tyres can be considered wornout. This represents the legal minimum treaddepth; most authorities recommend renewingany tyre on which the tread depth is 2 mm orless. Tread wear can be monitored with asimple, inexpensive device known as a treaddepth indicator (see illustration). 3 Note any abnormal tyre wear (seeillustration overleaf). Tread pattern irregular-ities such as cupping, flat spots and morewear on one side than the other areindications of front end alignment and/orwheel balance problems. If any of theseconditions are noted, take the vehicle to a tyrespecialist to correct the problem. 4 Look closely for cuts, punctures andembedded nails or tacks. Sometimes, after anail has embedded itself in the tread, a tyrewill hold air pressure for a short time, or may

1•9

4.22 The windscreen washer fluid reservoiris located in the right front corner of theengine compartment on most models

4.16 The brake fluid level should be keptabove the MIN mark on the translucentreservoir - unscrew the cap to add fluid

4.15 Adding hydraulic fluid to the clutchfluid reservoir

5.4a If a slow puncture is suspected,check the valve core first to make sure it’s

tight

5.2 Use a tyre tread depth indicator tomonitor tyre wear - they are available at

car accessory shops and service stations,and cost very little

1

Weekly Checks

leak down very slowly. If a slow puncturepersists, check the valve stem core to makesure it is tight (see illustration). Examine thetread for an object that may have embeddeditself in the tyre, or for a previous repair thatmay have begun to leak. If a puncture issuspected, it can be easily verified byspraying a solution of soapy water onto thepuncture (see illustration). The soapysolution will bubble if there is a leak. Unlessthe puncture is unusually large, a tyrespecialist can usually repair the tyre.5 Carefully inspect the inner sidewall of eachtyre for evidence of brake fluid leakage. If yousee any, inspect the brakes immediately.6 Correct air pressure adds miles to the lifespan of the tyres, improves fuel economy, andenhances overall ride quality. A tyre pressuregauge is essential.

7 Always check the tyre pressures when thetyres are cold (ie before driving the vehicle).

Checking the pressures when the tyres arewarm, or hot, will result in higher readings,due to heat expansion. On no account shouldair be let out of the tyres in this case, or thetyres will effectively be under-inflated whencold.8 Unscrew the valve cap protruding from thewheel or hubcap, and push the gauge firmlyonto the valve stem (see illustration). Notethe reading on the gauge, and compare the

figure to the recommended tyre pressuresshown in the Specifications listed at thebeginning of this Chapter. Be sure to refit thevalve cap to keep dirt and moisture out of thevalve stem mechanism. Check all four tyresand, if necessary, add enough air to bringthem to the recommended pressure. 9 Don’t forget to keep the spare tyre inflatedto the specified pressure.

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5.8 To extend the life of the tyres, checkthe air pressure at least once a week withan accurate gauge (don’t forget the spare!)

5.4b If the valve core is tight, raise thevehicle, and spray a soapy water solution

onto the tread as the tyre is turned slowly -leaks will cause small bubbles to appear

Tyre tread wear patterns

Shoulder Wear

Underinflation (wear on both sides)Under-inflation will cause overheating of thetyre, because the tyre will flex too much, andthe tread will not sit correctly on the roadsurface. This will cause a loss of grip andexcessive wear, not to mention the danger ofsudden tyre failure due to heat build-up.Check and adjust pressuresIncorrect wheel camber (wear on one side)Repair or renew suspension partsHard corneringReduce speed!

Centre Wear

OverinflationOver-inflation will cause rapid wear of thecentre part of the tyre tread, coupled withreduced grip, harsher ride, and the danger ofshock damage occurring in the tyre casing.Check and adjust pressures

If you sometimes have to inflate your car’styres to the higher pressures specified formaximum load or sustained high speed, don’tforget to reduce the pressures to normalafterwards.

Uneven Wear

Front tyres may wear unevenly as a result ofwheel misalignment. Most tyre dealers andgarages can check and adjust the wheelalignment (or "tracking") for a modest charge.Incorrect camber or castorRepair or renew suspension partsMalfunctioning suspensionRepair or renew suspension partsUnbalanced wheelBalance tyresIncorrect toe settingAdjust front wheel alignmentNote: The feathered edge of the tread whichtypifies toe wear is best checked by feel.

Weekly Checks

Keep an accurate gauge inthe glove compartment. Thepressure gauges attached tothe nozzles of air hoses atservice stations are ofteninaccurate.

Every 6000 miles or 6 months, whichever comes first

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6.17a Unscrew the bolt . . .

1

Every 6000 miles

6 Engine oil and filter change 1Warning: Prolonged skin contactwith used engine oil ishazardous. Use a barrier cream

and wear gloves during this procedure.Change out of oil-soaked clothingimmediately.

1 Make sure that you have all the necessarytools before you begin this procedure (seeillustration). You should also have plenty of ragsor newspapers handy for mopping up oil spills

2 Start the engine and allow it to reachnormal operating temperature - oil and sludgewill flow more easily when warm. If new oil, afilter or tools are needed, use the vehicle to goand get them, thus warming up the engine oilat the same time.3 Park on a level surface, and switch off theengine when it’s warmed up. Remove the oilfiller cap from the valve cover. 4 Access to the oil drain plug and filter will beimproved if the vehicle can be lifted on a hoist,driven onto ramps, or supported by axlestands.

Warning: DO NOT work under avehicle supported only by ahydraulic or scissors-type jack -always use axle stands!

5 If you haven’t changed the oil on thisvehicle before, get under it, and locate thedrain plug and the oil filter. Note that on someengines, the oil filter is located on the top left-hand side of the engine. The exhaustcomponents will be hot as you work, so notehow they are routed to avoid touching them. 6 Being careful not to touch the hot exhaustcomponents, position a drain pan under theplug in the bottom of the engine.7 Clean the area around the plug, thenremove the plug (see illustration). It’s a goodidea to wear a rubber glove while unscrewingthe plug the final few turns, to avoid beingscalded by hot oil. Hold the drain plug against

the threads as you unscrew it, then pull itaway from the drain hole suddenly. This willplace your arm out of the way of the hot oil, aswell as reducing the chances of dropping thedrain plug into the drain pan. 8 It may be necessary to move the drain panslightly as oil flow slows to a trickle. Inspectthe old oil for the presence of metal particles,which could give early warning of enginewear. 9 After all the oil has drained, wipe off thedrain plug with a clean rag. Any small metalparticles clinging to the plug wouldimmediately contaminate the new oil.10 Refit the plug and tighten it securely. Usea new washer if necessary.11 Move the drain pan into position under theoil filter.

Canister-type oil filter12 Loosen the spin-off type oil filter byturning it anti-clockwise with a filter spanner.Any standard filter spanner will work.13 Sometimes the spin-off type oil filter isscrewed on so tightly that it can’t be easilyloosened. If it is, punch a metal bar or longscrewdriver directly through it, and use it as aT-bar to turn the filter. Be prepared for oil tospurt out of the canister as it’s punctured. 14 Once the filter is loose, use your hands tounscrew it from the block. Just as the filter isdetached from the block, immediately tilt theopen end up to prevent oil inside the filterfrom spilling out. 15 Using a clean rag, wipe off the mountingsurface on the block. Also, make sure thatnone of the old sealing ring remains stuck tothe mounting surface. It can be removed witha scraper if necessary. 16 Compare the old filter with the new one,to make sure they are the same type. Smearsome engine oil on the rubber sealing ring ofthe new filter, and screw it into place (seeillustration). Overtightening the filter willdamage the sealing ring, so don’t use a filterspanner. Most filter manufacturersrecommend tightening the filter by hand only.Normally, they should be tightened three-quarters of a turn after the sealing ringcontacts the block, but be sure to follow thedirections on the filter or container.

6.1 These tools are required whenchanging the engine oil and filter

1 Drain pan - It should be fairly shallow indepth, but wide enough to prevent spills

2 Rubber gloves - When removing the drainplug and filter, you will get oil on yourhands (the gloves will prevent burns)

3 Socket bar - Sometimes the oil drain plugis tight, and a long bar is needed to loosenit. The correct-size ring spanner may workjust as well

4 Socket - To be used with the bar or aratchet (must be the correct size to fit thedrain plug - six-point preferred)

5 Filter spanner - This is a metal band-typespanner, which requires clearance aroundthe filter to be effective. This tool is notrequired on all engines.

6 Filter spanner - This type fits on the bottomof the filter and can be turned with a ratchetor breaker bar (different-size spanners areavailable for different types of filters) Thistool is not required on all engines.

6.7 Using a ring spanner to remove the oildrain plug

6.16 Lubricate the oil filter sealing ringwith clean engine oil before refitting the

filter on the engine

Frequent oil changes are themost important preventivemaintenance procedures thatcan be done by the home

mechanic. As engine oil ages, itbecomes diluted and contaminated,which leads to premature engine wear.

Cartridge-type oil filter17 Some models are equipped with acartridge-type oil filter. Unscrew the bolt,remove the cover, and lift the filter out (seeillustrations).18 Compare the new cartridge with the oldone, to make sure they are the same type,then lower it into the housing.19 Using a clean rag, wipe off the mountingsurface of the housing and cover. If necessary,renew the rubber O-ring (see illustration).Smear some clean oil on the O-ring and refitthe cover and bolt. Tighten the bolt securely.

All models20 Remove all tools and materials from underthe vehicle, being careful not to spill the oilfrom the drain pan, then lower the vehicle.21 Add new oil to the engine through the oilfiller cap in the valve cover. Use a funnel toprevent oil from spilling onto the top of theengine. Pour the specified quantity of fresh oilinto the engine. Wait a few minutes to allow theoil to drain into the sump, then check the levelon the dipstick (see Section 4 if necessary). Ifthe oil level is correct, refit the filler cap. 22 Start the engine and run it for about aminute. The oil pressure warning light maytake a few seconds to go out while the newfilter fills with oil; don’t rev the engine whilethe light is on. While the engine is running,look under the vehicle, and check for leaks atthe sump drain plug and around the oil filter. If

either one is leaking, stop the engine andtighten the plug or filter slightly. 23 Wait a few minutes, then recheck the levelon the dipstick. Add oil as necessary.24 During the first few days after an oilchange, make it a point to check frequentlyfor leaks and proper oil level. 25 The old oil drained from the engine cannotbe re-used in its present state, and should bediscarded. Oil reclamation centres and someservice stations will accept the oil, which canbe recycled. After the oil has cooled, it can betransferred into a container for transport to adisposal site.

7 Power steering fluid levelcheck 1

1 Check the power steering fluid levelperiodically to avoid steering systemproblems, such as damage to the pump.Proceed as follows.

Caution: Do not hold the steeringwheel against either stop (full-leftor full-right lock) for more thanfive seconds. If you do, the powersteering pump could be damaged.

2 On some models, the power steering fluidreservoir is located on the left side of theengine compartment, and has a twist-off capwith an integral fluid level dipstick (seeillustration). Other models use a hydraulicpower steering and brake servo system whichcombines the fluid in one reservoir, located atthe right rear corner of the enginecompartment.3 Park the vehicle on level ground, and applythe handbrake.4 On models with a fluid dipstick, run theengine until it has reached normal operatingtemperature. With the engine at idle, turn thesteering wheel back and forth several times toget any air out of the steering system. Switchoff the engine, remove the cap by turning itanti-clockwise, wipe the dipstick clean, andrefit the cap. Remove the cap again, and notethe fluid level. It must be between the twolines (see illustration). 5 On hydraulic servo models, pump the brakepedal about ten times or until the pedal is firm.Remove the nut, lift the cap off, and makesure the fluid is within 6.0 mm of the top of thereservoir.6 Add small amounts of fluid until the level iscorrect (see illustration).

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7.6 Adding fluid to the power steeringreservoir

7.4 The power steering fluid level shouldbe kept between the two arrows near the

upper step on the dipstick

7.2 The power steering fluid reservoir(arrowed) is located on the left side of the

engine compartment

6.19 Renewing the rubber O-ring in thecover

6.17c . . . and lift out the cartridge

Every 6000 miles

6.17b . . . remove the cover . . .

Note: It isantisocial andillegal to dumpoil down thedrain. To findthe location ofyour local oilrecyclingbank, call thisnumber free.

Caution: Do not overfill thereservoir. If too much fluid isadded, remove the excess with aclean syringe. Refit the cap.

7 If frequent topping-up is needed, check thepower steering hoses and connections forleaks and wear (see Section 10).8 Check the condition and tension of thedrivebelt (see Section 11).

8 Automatic transmission fluidlevel check 1

Caution: The use of transmissionfluid other than the type listed inthis Chapter’s Specificationscould result in transmissionmalfunctions or failure.

1 The automatic transmission fluid should becarefully maintained. Low fluid level can leadto slipping or loss of drive, while overfillingcan cause foaming and loss of fluid. Eithercondition can cause transmission damage. 2 Since transmission fluid expands as it heatsup, the fluid level should only be checkedwhen the transmission is warm (at normaloperating temperature). If the vehicle has justbeen driven over 20 miles (32 km), thetransmission can be considered warm. Youcan also check the fluid level when thetransmission is cold. If the vehicle has notbeen driven for over five hours and the fluid isabout room temperature (20°C), thetransmission is cold. However, the fluid levelis normally checked with the transmissionwarm, to ensure accurate results.

Caution: If the vehicle has justbeen driven for a long time athigh speed or in city traffic, in hotweather, or if it has been pulling

a trailer, an accurate fluid level readingcannot be obtained. Allow the trans-mission to cool down for about 30 minutes.

3 Immediately after driving the vehicle, park iton a level surface, apply the handbrake andstart the engine. While the engine is idling,depress the brake pedal and move the

selector lever through all the gear ranges,beginning and ending in Park. 4 The automatic transmission dipstick tube islocated in the left rear corner of the enginecompartment. 5 With the engine still idling, pull the dipstickout of the tube (see illustration), wipe it offwith a clean rag, push it all the way back intothe tube and withdraw it again, then note thefluid level. 6 The level should be between the two marks(see illustration). If the level is low, add thespecified automatic transmission fluid throughthe dipstick tube - use a clean funnel,preferably equipped with a fine mesh filter, toprevent spills.

Caution: Be careful not tointroduce dirt into thetransmission when topping up.

7 Add just enough of the recommended fluidto fill the transmission to the proper level. Ittakes about half a litre to raise the level fromthe low mark to the high mark when the fluidis hot, so add the fluid a little at a time, andkeep checking the level until it’s correct.8 The condition of the fluid should also bechecked along with the level. If the fluid isblack or a dark reddish-brown colour, or if itsmells burned, it should be changed (seeSection 28). If you are in doubt about itscondition, purchase some new fluid, andcompare the two for colour and smell.

9 Tyre rotation 11 The tyres can be rotated at the specifiedintervals, or whenever uneven wear is noticed.However, bear in mind that if rotationsucceeds in making all the tyres wear evenly,you will eventually have to renew all four atonce. Since the vehicle will be raised and thewheels removed anyway, check the brakesalso (see Section 26). Note: Even if you don’trotate the tyres, at least check the wheel bolttightness. 2 It is recommended that the tyres be rotated

in a specific pattern (see illustration) so thattheir direction of rotation remains the same. 3 Refer to the information in “Jacking andtowing” at the front of this manual for theproper procedure to follow when raising thevehicle and changing a tyre.4 The vehicle must be raised on a hoist orsupported on axle stands to get all four tyresoff the ground. Make sure the vehicle is safelysupported! 5 After the rotation procedure is finished,check and adjust the tyre pressures asnecessary, and be sure to check the wheelbolt tightness.

10 Underbonnet hose checkand renewal 3

Warning: Renewal of airconditioning hoses must be leftto a dealer service department orair conditioning specialist having

the equipment to depressurise the systemsafely. Never disconnect air conditioninghoses or components until the system hasbeen depressurised.

General 1 High temperatures under the bonnet cancause deterioration of the rubber and plastichoses used for various systems. Periodicinspection should be made for cracks, looseclamps, material hardening, and leaks.2 Information specific to the cooling systemcan be found in Section 22, while the brakingsystem is covered in Section 26.3 Most (but not all) hoses are secured withclamps. Where clamps are used, check to besure they haven’t lost their tension, allowingthe hose to leak. If clamps aren’t used, makesure the hose has not expanded and/orhardened where it slips over the fitting,allowing it to leak.

Vacuum hoses 4 It’s quite common for vacuum hoses,especially those in the emissions system, tobe colour-coded or identified by coloured

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9.2 The tyre rotation pattern for thesemodels

8.6 With the fluid hot, the level should bekept between the two dipstick notches,

preferably near the upper one

8.5 The automatic transmission fluiddipstick (arrowed) is located near thebulkhead on the left side of the engine

compartment

1

Every 6000 miles

stripes moulded into them. Various systemsrequire hoses with different wall thicknesses,collapse resistance and temperatureresistance. When fitting new hoses, be surethe new ones are made of the same material.5 Often the only effective way to check ahose is to remove it completely from thevehicle. If more than one hose is removed, besure to label the hoses and fittings to ensurecorrect refitting. 6 When checking vacuum hoses, be sure toinclude any plastic T-fittings in the check.Inspect the connections for cracks whichcould cause leakage. 7 A small piece of vacuum hose can be usedas a stethoscope to detect vacuum leaks.Hold one end of the hose to your ear andprobe around vacuum hoses and fittings,listening for the “hissing” sound characteristicof a vacuum leak.

Warning: When probing with thevacuum hose stethoscope, becareful not to touch movingengine components such as thedrivebelt, cooling fan, etc.

Fuel hoses Warning: There are certainprecautions which must be takenwhen servicing or inspecting fuelsystem components. Work in a

well-ventilated area, and do not allow openflames (cigarettes, appliance pilot lights,etc.) or bare light bulbs near the workarea. Mop up any spills immediately, anddo not store fuel-soaked rags where theycould ignite. If you spill any fuel on yourskin, rinse it off immediately with soap andwater. When you perform any kind of workon the fuel system, wear safety glasses,and have a fire extinguisher on hand.

8 The fuel hoses are usually under pressure,so if any fuel hoses are to be disconnected,be prepared to catch spilled fuel.

Warning: On vehicles equippedwith fuel injection, you mustdepressurise the fuel systembefore servicing the fuel hoses.Refer to Chapter 4 for details.

9 Check all rubber fuel hoses for deteriorationand chafing. Check especially for cracks inareas where the hose bends, and just beforeconnectors, such as where a hose attaches tothe fuel pump or fuel filter, for example.10 Only high-quality fuel hose should beused. Never, under any circumstances, useunreinforced vacuum hose, clear plastictubing or water hose for fuel hoses. 11 Band-type clamps are commonly used onfuel hoses. These clamps often lose theirtension over a period of time, and can be“sprung” during removal. Renew all band-typeclamps with screw clamps whenever a hose isrenewed.

Metal lines 12 Sections of metal line are often usedbetween the fuel pump and fuel injectionsystem. Check carefully to make sure the lineisn’t bent, crimped or cracked. 13 If a section of metal line must be renewed,use seamless steel tubing only, since copperand aluminium tubing do not have thestrength necessary to withstand the vibrationcaused by the engine. 14 Check the metal brake lines where theyenter the master cylinder and brakeproportioning or ABS unit (if used) for cracksin the lines and loose fittings. Any sign ofbrake fluid leakage calls for an immediatethorough inspection of the braking system.

Power steering hoses 15 Check the power steering hoses for leaks,loose connections and worn clamps. Tightenloose connections. Worn clamps or leakyhoses should be renewed.

11 Drivebelt check, adjustmentand renewal 1

Check1 The drivebelts, sometimes called V-belts orsimply “fan” belts, are located at the front ofthe engine, and play an important role in theoverall operation of the vehicle and its

components. Due to their function andmaterial make-up, the belts are prone tofailure after a period of time, and should beinspected and adjusted periodically to preventmajor engine damage.2 The number of belts used on a particularvehicle depends on the accessories fitted.Drivebelts are used to turn the alternator,power steering pump, water pump, and airconditioning compressor. Depending on thepulley arrangement, a single belt may be usedto drive more than one of these components.3 With the engine switched off, open thebonnet and locate the various belts at thefront of the engine. Using your fingers (and atorch, if necessary), move along the belts,checking for cracks and separation of the beltplies. Also check for fraying and glazing,which gives the belt a shiny appearance (seeillustration). Both sides of the belts should beinspected, which means you will have to twisteach belt to check the underside.4 The tension of each belt is checked bypushing firmly with your thumb and seeinghow much the belt moves (deflects). Measurethe deflection with a ruler (see illustration). Agood rule of thumb is that the belt shoulddeflect 6 mm if the distance from pulleycentre-to-pulley centre is between 180 and280 mm. The belt should deflect 13 mm if thedistance from pulley centre-to-pulley centre isbetween 300 and 400 mm.

Adjustment5 If it is necessary to adjust the belt tension,either to make the belt tighter or looser, it isdone by moving a belt-driven accessory on itsbracket. (When the same belt drives morethan one accessory, normally only oneaccessory is moved when makingadjustment.)6 For each component, there will be anadjusting bolt and a pivot bolt. Both boltsmust be loosened slightly to enable you tomove the component. On some components,the drivebelt tension can be adjusted byturning an adjusting bolt after loosening thelockbolt (see illustration).7 After the two bolts have been loosened,

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11.6 Loosen the nut on the other end ofthe adjuster bolt (arrowed) and turn the

bolt to increase or decrease tension on thedrivebelt

11.4 Measuring drivebelt deflection with astraightedge and ruler

11.3 Here are some of the more commonproblems associated with drivebelts

(check the belts very carefully to preventan untimely breakdown)

Every 6000 miles

move the component away from the engine totighten the belt, or towards the engine toloosen the belt. Hold the accessory inposition, and check the belt tension. If it iscorrect, tighten the two bolts until just tight,then recheck the tension. If the tension is stillcorrect, tighten the bolts.8 It will often be necessary to use some sortof lever to move the accessory while the beltis adjusted. If this must be done to gain theproper leverage, be very careful not todamage the component being moved, or thepart being prised against.

Renewal9 To renew a belt, follow the instructionsabove for adjustment, but remove the beltfrom the pulleys.10 In some cases, you will have to removemore than one belt, because of theirarrangement on the front of the engine.Because of this, and the fact that belts willtend to fail at the same time, it is wise torenew all belts together. Mark each belt andits appropriate pulley groove, so all renewedbelts can be fitted in their proper positions.11 It is a good idea to take the old belts withyou when buying new ones, in order to makea direct comparison for length, width anddesign.12 Recheck the tension of new belts after afew hundred miles.

12 Engine idle speed and COlevel check and adjustment 4

Note: The engine should be at normaloperating temperature, with correct ignitiontiming and valve clearances (whereadjustable). The air filter should be in goodcondition, and all electrical components(including the air conditioning, where fitted)should be switched off.

Carburettor1 Connect a tachometer and exhaust gasanalyser (CO meter) to the engine.2 Start the engine and allow it to idle.3 Check that the idle speed is as given in theSpecifications. Adjustment of the idle speed isonly possible on the 2B4 carburettor. Turn thecarburettor idle speed adjustment screw untilthe engine idles at the correct speed (seeillustration).4 If the idle speed is low on the 2BEcarburettor, and all wiring to the carburettor isin good condition, it is possible to connect aresistance into the control circuit. This shouldbe carried out by your BMW dealer.5 Check that the CO reading is as given in theSpecifications. If not, turn the carburettor idlemixture adjustment screw until the mixture iscorrect (see illustration).

L-Jetronic6 Connect a tachometer and CO meter to theengine. BMW technicians use a special COtester with a probe connected into theexhaust manifold, but the normal type oftester which locates in the exhaust tailpipecan be used instead. Note however that onmodels with a catalytic converter, meaningfulCO readings will not be obtained at thetailpipe.7 Start the engine and allow it to idle.8 Check that the idle speed is as given inSpecifications. If not, remove the tamperproofcap from the throttle housing, and turn the idleadjustment screw until the speed is correct.9 Check that the CO reading is as given in theSpecifications. The mixture control screw islocated on the airflow meter, and a special

tool (BMW number 13 1 060) may be requiredto make the adjustment.

Motronic10 Connect a tachometer and CO meter tothe engine. BMW technicians use a specialCO tester with a probe connected into theexhaust manifold, but the normal type oftester which locates in the exhaust tailpipemay be used instead. Note however that onmodels with a catalytic converter, meaningfulCO readings will not be obtained at thetailpipe.11 It is not possible to adjust the idle speedmanually, as the idle air stabiliser valve isactivated by the electronic control unit. If theidle speed is not within the specified rangewith the engine at normal operatingtemperature, check for a leak in the air inletsystem, and also check the operation of theidle air stabiliser valve (see Chapter 4).12 Check that the CO reading is as given inthe Specifications. If adjustment is required,prise out the tamperproof plug from theairflow meter, and turn the adjustment screwto set the CO content (on some models, anAllen key will be required). Fit a newtamperproof plug on completion (seeillustrations).

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12.12a Removing the tamperproof plugfrom the airflow meter

12.5 Mixture adjustment screw (2) on the2B4 carburettor

12.3 Idle speed adjustment screw on the2B4 carburettor (shown with the

carburettor removed)

12.12b Adjusting the CO on the Motronicsystem

1

Every 6000 miles

13 Battery check, maintenanceand charging 2

Check and maintenanceWarning: Certain precautionsmust be followed when checkingand servicing the battery.Hydrogen gas, which is highly

flammable, is always present in the batterycells, so keep lighted tobacco and all otherflames and sparks away from it. Theelectrolyte inside the battery is actuallydilute sulphuric acid, which will causeinjury if splashed on your skin or in your

eyes. It will also ruin clothes and paintedsurfaces. When disconnecting the batterycables, always detach the negative cablefirst, and connect it last!1 Battery maintenance is an importantprocedure, which will help ensure that you arenot stranded because of a dead battery.Several tools are required for this procedure(see illustration).2 Before servicing the battery, always switchoff the engine and all accessories, anddisconnect the cable from the negativeterminal of the battery.

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you have

the correct activation code beforedisconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.3 A low-maintenance battery is standardequipment. The cell caps can be removed anddistilled water can be added, if necessary.Later models may be fitted with a“maintenance-free” battery, which is sealed.4 Remove the caps and check the electrolytelevel in each of the battery cells. It must beabove the plates. There’s usually a split-ringindicator in each cell to indicate the correctlevel. If the level is low, add distilled wateronly, then refit the cell caps.

Caution: Overfilling the cells maycause electrolyte to spill overduring periods of heavy charging,causing corrosion and damage tonearby components.

5 If the positive terminal and cable clamp onyour vehicle’s battery is equipped with arubber protector, make sure that it’s not tornor damaged. It should completely cover theterminal.6 The external condition of the battery shouldbe checked periodically. Look for damagesuch as a cracked case.7 Check the tightness of the battery cableclamps to ensure good electrical connections.Check the entire length of each cable, lookingfor cracked or abraded insulation and frayedconductors.8 If corrosion (visible as white, fluffy deposits)is evident, remove the cables from theterminals, clean them with a battery brush,and reconnect them (see illustrations).Corrosion can be kept to a minimum by fittingspecially treated washers available at caraccessory shops, or by applying a layer ofpetroleum jelly or suitable grease to the

Every 12 000 miles or 12 months, whichever comes first

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13.8d When cleaning the cable clamps, allcorrosion must be removed (the inside of

the clamp is tapered to match the taper onthe post, so don’t remove too much

material)

13.8c Regardless of the type of tool usedon the battery posts, a clean, shiny surface

should be the result

13.1 Tools and materials required forbattery maintenance

1 Face shield/safety goggles - Whenremoving corrosion with a brush, the acidicparticles can easily fly up into your eyes

2 Baking soda - A solution of baking soda andwater can be used to neutralise corrosion

3 Petroleum jelly - A layer of this on thebattery posts will help prevent corrosion

4 Battery post/cable cleaner - This wire-brush cleaning tool will remove all traces ofcorrosion from the battery posts and cableclamps

5 Treated felt washers - Placing one ofthese on each post, directly under thecable clamps, will help prevent corrosion

6 Puller - Sometimes the cable clamps arevery difficult to pull off the posts, even afterthe nut/bolt has been completely loosened.This tool pulls the clamp straight up and offthe post without damage

7 Battery post/cable cleaner - Here isanother cleaning tool which is a slightlydifferent version of No 4 above, but it doesthe same thing

8 Rubber gloves - Another safety item toconsider when servicing the battery;remember that’s acid inside the battery!

13.8b Removing a cable from the batterypost with a spanner - sometimes special

battery pliers are required for thisprocedure, if corrosion has caused

deterioration of the nut (always remove theearth cable first, and connect it last!)

13.8a Battery terminal corrosion usuallyappears as light, fluffy powder

Every 12 000 miles

terminals and cable clamps after they areassembled.9 Make sure that the battery carrier is in goodcondition, and that the hold-down clamp boltis tight. If the battery is removed (see Chap-ter 5 for the removal and refitting procedure),make sure that no parts remain in the bottomof the carrier when it’s refitted. When refittingthe hold-down clamp, don’t overtighten thebolt.10 Corrosion on the carrier, battery case andsurrounding areas can be removed with asolution of water and baking soda. Apply themixture with a small brush, let it work, thenrinse it off with plenty of clean water.11 Any metal parts of the vehicle damagedby corrosion should be coated with a zinc-based primer, then painted.12 Additional information on the battery andjump starting can be found in Chapter 5 andthe front of this manual.

ChargingNote: The manufacturer recommends thebattery be removed from the vehicle forcharging, because the gas which escapesduring this procedure can damage the paint orinterior, depending on the location of thebattery. Fast charging with the battery cablesconnected can result in damage to theelectrical system.13 Remove all of the cell caps (if applicable),and cover the holes with a clean cloth toprevent spattering electrolyte. Disconnect the

battery negative cable, and connect thebattery charger leads to the battery posts(positive to positive, negative to negative),then plug in the charger. Make sure it is set at12 volts if it has a selector switch.

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation code

before disconnecting the battery. Note: If,after connecting the battery, the wronglanguage appears on the instrument paneldisplay, refer to page 0-7 for the languageresetting procedure.14 If you’re using a charger with a rate higherthan two amps, check the battery regularlyduring charging to make sure it doesn’toverheat. If you’re using a trickle charger, youcan safely let the battery charge overnightafter you’ve checked it regularly for the firstcouple of hours. Where a maintenance-freebattery is fitted, special precautions may benecessary when charging it (for example, thecharge rate is normally very low). There maybe a warning label on the battery, but if not,consult a BMW dealer or auto-electrician.15 If the battery has removable cell caps,measure the specific gravity with ahydrometer every hour during the last fewhours of the charging cycle. Hydrometers areavailable inexpensively from car accessoryshops - follow the instructions that come withthe hydrometer. Consider the battery chargedwhen there’s no change in the specific gravityreading for two hours, and the electrolyte inthe cells is gassing (bubbling) freely. Thespecific gravity reading from each cell shouldbe very close to the others. If not, the batteryprobably has a bad cell(s), and a new oneshould be fitted.16 Some maintenance-free (sealed) batterieshave built-in hydrometers on the top,indicating the state of charge by the colourdisplayed in the hydrometer window.Normally, a bright-coloured hydrometerindicates a full charge, and a dark hydrometerindicates the battery still needs charging.Check the battery manufacturer’s instructionsto be sure you know what the colours mean.

17 If the battery is sealed and has no built-inhydrometer, you can connect a digitalvoltmeter across the battery terminals tocheck the charge. A fully-charged batteryshould read 12.6 volts or higher.18 Further information on the battery andjump starting can be found in Chapter 5 andat the front of this manual.

14 Spark plug check andrenewal 1

1 Before beginning, obtain the necessarytools, which will include a spark plug socketand a set of feeler blades. Special spark pluggap gauges can be obtained from certainspark plug manufacturers (see illustration).2 The best procedure to follow whenrenewing the spark plugs is to purchase thenew spark plugs beforehand, adjust them tothe proper gap, and then renew each plug oneat a time. When buying the new spark plugs, itis important to obtain the correct plugs foryour specific engine. This information can befound in the Specifications section in the frontof this Chapter.3 With the new spark plugs at hand, allow theengine to cool completely before attemptingplug removal. During this time, each of thenew spark plugs can be inspected for defectsand the gaps can be checked.4 The gap is checked by inserting the properthickness gauge between the electrodes at thetip of the plug (see illustration). The gapbetween the electrodes should be the same asthat given in the Specifications. The wireshould just touch each of the electrodes. If thegap is incorrect, use the notched adjuster tobend the curved side of the electrode slightlyuntil the proper gap is achieved (seeillustration). Note: When adjusting the gap of anew plug, bend only the base of the earthelectrode, do not touch the tip. If the earthelectrode is not exactly over the centreelectrode, use the notched adjuster to align thetwo. Check for cracks in the porcelain insulator,indicating the spark plug should not be used.

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14.4b To change the gap, bend the earthelectrode only, as indicated by the arrows,and be very careful not to crack or chip theporcelain insulator surrounding the centre

electrode

14.4a Spark plug manufacturersrecommend using a wire-type gauge when

checking the gap - if the wire does notslide between the electrodes with a slight

drag, adjustment is required

14.1 Tools required for changing sparkplugs

1 Spark plug socket - This will have specialpadding inside to protect the spark plug’sporcelain insulator

2 Torque wrench - Although not mandatory,using this tool is the best way to ensure theplugs are tightened properly

3 Ratchet - Standard hand tool to fit thespark plug socket

4 Extension - Depending on model andaccessories, you may need specialextensions and universal joints to reach oneor more of the plugs

5 Spark plug gap gauge - This gauge forchecking the gap comes in a variety ofstyles. Make sure the gap for your engine isincluded. Feeler blades may be usedinstead

1

Every 12 000 miles

5 With the engine cool, remove the HT leadfrom one spark plug. Do this by grabbing theconnector at the end of the wire, not the leaditself (see illustration). Sometimes it isnecessary to use a twisting motion while theconnector and HT lead are pulled free.6 If compressed air is available, use it to blowany dirt or foreign material away from thespark plug area. A common bicycle pump willalso work. The idea here is to eliminate thepossibility of debris falling into the cylinder asthe spark plug is removed.7 Place the spark plug socket over the plug,and remove it from the engine by turning itanti-clockwise (see illustration).8 Compare the spark plug with those shownin the accompanying photos to get anindication of the overall running condition ofthe engine.9 Apply a little copper-based anti-seizecompound to the threads of the new sparkplug. Locate the plug into the head, screwingit in with your fingers until it no longer turns,then tighten it with the socket. If available, usea torque wrench to tighten the plug to ensurethat it is seated correctly. The correct torquefigure is included in this Chapter’s Specifi-cations.

10 Before pushing the HT lead onto the end ofthe plug, inspect it as outlined in Section 15.11 Attach the HT lead to the new spark plug,again using a twisting motion on theconnector until it is firmly seated on the sparkplug.12 Follow the above procedure for theremaining spark plugs, renewing them one ata time to prevent mixing up the spark plug HTleads.

15 Spark plug HT leads,distributor cap and rotor -check and renewal

11 The spark plug HT leads should be checkedat the recommended intervals, and whenevernew spark plugs are fitted in the engine.2 Begin this procedure by making a visualcheck of the spark plug HT leads while theengine is running. In a darkened garage (makesure there is ventilation) start the engine andobserve each HT lead. Be careful not to comeinto contact with any moving engine parts. Ifthere is a break in the wire, you will see arcingor a small spark at the damaged area. If arcingis noticed, make a note to obtain new HTleads, then allow the engine to cool.3 Disconnect the battery negative cable.

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation codebefore disconnecting the battery.

Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.4 The HT leads should be inspected one at atime to prevent mixing up the firing order,which is essential for proper engine operation.5 Disconnect the HT lead from the sparkplug. Do not pull on the lead itself, only on theconnector.6 Inspect inside the connector for corrosion,which will look like a white crusty powder.Push the HT lead and connector back ontothe end of the spark plug. It should be a tightfit on the plug end. If it is not, remove the leadand use pliers to carefully crimp the metalterminal inside the connector until it fitssecurely on the end of the spark plug.7 Using a clean rag, wipe the entire length ofthe HT lead to remove any built-up dirt andgrease. Once the lead is clean, check forburns, cracks and other damage. Do not bendthe lead excessively, since the conductormight break.8 Disconnect the HT lead from the distributor.Again, pull only on the connector. Check forcorrosion and a tight fit in the same manner asthe spark plug end. Renew the HT lead in thedistributor if necessary.9 Check the remaining spark plug HT leads,making sure they are securely fastened at thedistributor and spark plug when the check iscomplete.10 If new spark plug HT leads are required,purchase a set for your specific engine model.Lead sets are available pre-cut, with theconnectors already fitted. Remove and renewthe HT leads one at a time, to avoid mix-upsin the firing order.11 Loosen the screws or detach the clips andremove the distributor cap (see illustration).Remove the screws (if applicable) and pull therotor off the shaft (see illustration). Check thedistributor cap and rotor for wear. Look forcracks, carbon tracks and worn, burned orloose contacts (see illustrations). Renew thecap and rotor if defects are found. It iscommon practice to fit a new cap and rotorwhenever new spark plug HT leads are fitted.When fitting a new cap, remove the HT leadsfrom the old cap one at a time, and attach

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15.11b Use an Allen key to remove thescrews, then lift the rotor off the shaft

(later models)

15.11a On later models, loosen the screwsand detach the distributor cap up so you

can inspect the inside

14.7 Use a socket spanner with anextension to unscrew the spark plugs

14.5 When removing the spark plug HTleads, pull only on the connector

Every 12 000 miles

Where there might be difficulty ininserting the spark plugs into the sparkplug holes, or the possibility of cross-threading them into the head, a shortpiece of rubber or plastic tubing can befitted over the end of the spark plug.The flexible tubing will act as a universaljoint to help align the plug with the plughole, and should the plug begin tocross-thread, the hose will slip on thespark plug, preventing thread damage.

them to the new cap in the exact samelocation - do not simultaneously remove allthe HT leads, or firing order mix-ups mayoccur.

16 Manual transmissionlubricant level check 1

1 The transmission has a filler/level plugwhich must be removed to check the lubricantlevel. If the vehicle is raised to gain access tothe plug, be sure to support it safely - do notcrawl under a vehicle which is supported onlyby a jack! Note: The vehicle should be level togive an accurate lubricant check.2 Remove the plug from the side of the

transmission (see illustration) and use yourlittle finger to reach inside the plug from thehousing and feel the lubricant level. It shouldbe at or very near the bottom of the plug hole.3 If it isn’t, add the recommended lubricantthrough the plug hole with a syringe orsqueeze-bottle, until it just starts to run out ofthe hole. Refer to “Lubricants and fluids” atthe beginning of this Chapter for the correctlubricant type. The manual transmissions onsome later or high-performance models arefilled with automatic transmission fluid (ATF).Such transmissions normally carry a sticker tothis effect near the filler/level plug. Refer to aBMW dealer if still in doubt.4 Refit the plug and tighten securely. Checkfor leaks after the first few miles of driving.5 If regular topping-up is required, this canonly be due to a leak which should be foundand repaired before it becomes serious.

17 Differential lubricant levelcheck 1

1 The differential has a filler/level plug whichmust be removed to check the lubricant level.If the vehicle is raised to gain access to theplug, be sure to support it safely - do not

crawl under the vehicle when it’s supportedonly by the jack! Note: The vehicle should belevel to give an accurate lubricant check.2 Remove the filler/level plug from thedifferential (see illustration). Use an Allen keyto unscrew the plug.3 Use your little finger as a dipstick to makesure the lubricant level is up to the bottom ofthe plug hole. If not, use a syringe or squeeze-bottle to add the recommended lubricant untilit just starts to run out of the hole.4 Refit the plug and tighten it securely.5 If regular topping-up is required, this canonly be due to a leak which should be foundand repaired before it becomes serious.

18 Valve clearances -check and adjustment 3

Note: This procedure does not apply to theM40 engine, which has automatic adjusters.1 The valve clearances can be checked withthe engine hot or cold, but note that differentvalues are specified, depending on enginetemperature. If it is wished to check/adjust thevalve clearances with the engine hot, ifnecessary start and run the engine until itreaches normal operating temperature, thenshut it off.

Caution: If the clearances are checkedwith the engine hot, extra caremust be taken to avoid burns.2 Remove the valve cover

from the engine (see Chapter 2A).3 Turn the engine as necessary until No 1piston (front) is at Top Dead Centre (TDC) onthe compression stroke (see Chapter 2A).4 Check the valve clearances for No 1cylinder. The valve clearances can be found inthe Specifications Section at the beginning ofthis Chapter.5 The clearance is measured by inserting thespecified size feeler gauge between the endof the valve stem and the rocker arm adjustingeccentric. You should feel a slight amount of

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15.11d The rotor arm should be checkedfor wear and corrosion as indicated here (if in doubt about its condition, buy a new

one)

15.11c Shown here are some of thecommon defects to look for when

inspecting the distributor cap (if in doubtabout its condition, fit a new one)

18.6 The valve clearance is adjusted byturning the eccentric with a wire hook -

once the specified clearance is obtained,tighten the locknut with a spanner, then

remove the feeler gauge

17.2 Remove the differential filler/levelplug with an Allen key, and make sure the

lubricant is level with the bottom of thehole

16.2 Use a large Allen key to remove thefiller/level plug (arrowed) and check thelubricant level with your little finger. It

should be level with the bottom of the hole- if it’s low, add lubricant

1

Every 12 000 miles

drag when the feeler gauge is moved backand forth.6 If the gap is too large or too small, loosenthe locknut, insert a hook made from large-diameter metal wire, and rotate the eccentricto obtain the correct gap (see illustration).7 Once the gap has been set, hold theeccentric in position with the hook, andretighten the locknut securely. Recheck theclearance - sometimes it’ll change slightlywhen the locknut is tightened. If so, re-adjustuntil it’s correct.8 On the M10 engine, the valves are adjustedin the firing order, which is 1-3-4-2. Afteradjusting No 1 cylinder valves, rotate thecrankshaft half a turn (180º), then check andadjust the valves on No 3 cylinder. Repeat theprocedure on the remaining cylinders.9 On M20 and M30 engines, the valves areadjusted following the firing order, which is 1-5-3-6-2-4. After adjusting No 1 cylindervalves, rotate the crankshaft a third of a turn(120º), then check and adjust the valves on No5 cylinder. Repeat the procedure for theremaining cylinders.10 Refit the valve cover (use a new gasket)and tighten the mounting nuts evenly andsecurely.11 Start the engine and check for oil leakagebetween the valve cover and the cylinderhead.

19 Throttle linkage -check and lubrication 1

1 The throttle linkage should be checked andlubricated periodically to ensure its properoperation.2 Check the linkage to make sure it isn’tbinding.3 Inspect the linkage joints for looseness, andthe connections for corrosion and damage,renewing parts as necessary (seeillustration).4 Lubricate the connections with spraylubricant or lithium-based grease.

20 Air filter renewal 1Carburettor engines1 Release the spring clips, then unscrew thecentre nut and lift off the cover.2 Remove the air filter element, and wipeclean the air cleaner body and cover3 Fit the new air filter element, then refit thecover using a reversal of the removalprocedure.

Fuel injection engines4 Loosen the clamp on the air intake duct,and detach the duct (see illustration).

5 Release the air cleaner cover retaining clips(see illustration).6 Rotate the cover up, lift it off and lift theelement out, noting which way round it isfitted (see illustrations).7 Wipe the inside of the air cleaner housingwith a clean cloth, then fit the new element. Ifthe element is marked TOP, be sure themarked side faces up.8 Refit the cover and secure the clips.9 Connect the air duct and tighten the clampscrew.

21 Fuel system check 1Warning: Fuel is extremelyflammable, so take extraprecautions when you work onany part of the fuel system. Don’t

smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. Work in a well-ventilated area. If you spill any fuel on yourskin, rinse it off immediately with soap andwater. When you perform any kind of workon the fuel system, wear safety glasses,and have a fire extinguisher on hand. Mopup spills immediately, but do not storefuel-soaked rags where they could ignite.1 If you smell fuel while driving or after thevehicle has been sitting in the sun, inspect thefuel system immediately.2 Remove the fuel filler cap and inspect it fordamage and corrosion. The gasket shouldhave an unbroken sealing imprint. If thegasket is damaged or corroded, fit a new cap.3 Inspect the fuel feed and return lines forcracks. Make sure that the connectionsbetween the fuel lines and the carburettor orfuel injection system, and between the fuellines and the in-line fuel filter, are tight.

Warning: On fuel injectionmodels, the fuel system must bedepressurised before servicingfuel system components, asoutlined in Chapter 4.

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20.6b . . . and lift the air filter element out

20.6a Rotate the cover upwards . . .

20.5 Use a screwdriver to detach the aircleaner cover clips

20.4 Detach the duct from the air cleanerhousing

19.3 Check and lubricate the throttlelinkage at the points shown (arrowed) -

fuel injection engine shown

Every 12 000 miles

4 Since some components of the fuel system- the fuel tank and some of the fuel feed andreturn lines, for example - are underneath thevehicle, they can be inspected more easilywith the vehicle raised on a hoist. If that’s notpossible, raise the vehicle and support it onaxle stands or ramps.5 With the vehicle raised and safelysupported, inspect the fuel tank and filler neckfor punctures, cracks or other damage. Theconnection between the filler neck and thetank is particularly critical. Sometimes arubber filler neck will leak because of looseclamps or deteriorated rubber. Inspect all fueltank mounting brackets and straps, to be surethe tank is securely attached to the vehicle.

Warning: Do not, under anycircumstances, try to repair a fueltank (except rubbercomponents). A welding torch or

any naked flame can easily cause fuelvapours inside the tank to explode.6 Carefully check all flexible hoses and metallines leading away from the fuel tank. Checkfor loose connections, deteriorated hoses,crimped lines, and other damage. Repair orrenew damaged sections as necessary (seeChapter 4).

22 Cooling system check 11 Many major engine failures can beattributed to cooling system problems. If thevehicle has automatic transmission, theengine cooling system also plays an important

role in prolonging transmission life, because itcools the transmission fluid.2 The engine should be cold for the coolingsystem check, so perform the followingprocedure before the vehicle is driven for theday, or after it has been switched off for atleast three hours.3 Remove the radiator cap, doing so slowlyand taking adequate precautions againstscalding if the engine is at all warm. Clean thecap thoroughly, inside and out, with cleanwater. Also clean the filler neck on theradiator. The presence of rust or corrosion inthe filler neck means the coolant should bechanged (see Section 29). The coolant insidethe radiator should be relatively clean andclear. If it’s rust-coloured, drain the systemand refill with new coolant.4 Carefully check the radiator hoses and thesmaller-diameter heater hoses. Inspect eachcoolant hose along its entire length, renewingany hose which is cracked, swollen ordeteriorated (see illustration). Cracks willshow up better if the hose is squeezed. Payclose attention to hose clamps that secure thehoses to cooling system components. Hoseclamps can pinch and puncture hoses,resulting in coolant leaks.5 Make sure all hose connections are tight. Aleak in the cooling system will usually show upas white or rust-coloured deposits on the areaadjoining the leak. If wire-type clamps areused on the hoses, it may be a good idea toreplace them with screw-type clamps.6 Clean the front of the radiator (and, whereapplicable, the air conditioning condenser)with compressed air if available, or a softbrush. Remove all flies, leaves, etc,embedded in the radiator fins. Be extremelycareful not to damage the cooling fins or tocut your fingers on them.7 If the coolant level has been droppingconsistently and no leaks are detected, havethe radiator cap and cooling system pressure-tested.

23 Exhaust system check 11 The engine should be cold for this check,so perform the following procedure before thevehicle is driven for the day, or after it hasbeen switched off for at least three hours.Check the complete exhaust system from theengine to the end of the tailpipe. Ideally, theinspection should be done with the vehicle ona hoist, to give unrestricted access. If a hoistisn’t available, raise the vehicle and support itsecurely on axle stands or ramps.2 Check the exhaust pipes and connectionsfor evidence of leaks, severe corrosion, anddamage. Make sure that all brackets andmountings are in good condition, and thatthey are tight (see illustration).3 At the same time, inspect the underside ofthe body for holes, corrosion, open seams,

etc. which may allow exhaust gases to enterthe passenger compartment. Seal all bodyopenings with suitable sealant.4 Rattles and other noises can often betraced to the exhaust system, especially themountings and heat shields. Try to move thepipes, silencers (and, where applicable, thecatalytic converter). If the components cancome in contact with the body or suspensionparts, re-hang the exhaust system with newmountings.5 The running condition of the engine may bechecked by inspecting inside the end of thetailpipe. The exhaust deposits here are anindication of the engine’s state of tune. If thepipe is black and sooty, the engine may berunning too rich, indicating the need for athorough fuel system inspection.

24 Steering and suspensioncheck 1

Note: The steering linkage and suspensioncomponents should be checked periodically.Worn or damaged suspension and steeringlinkage components can result in excessiveand abnormal tyre wear, poor ride quality andvehicle handling, and reduced fuel economy.For detailed illustrations of the steering andsuspension components, refer to Chapter 10.

Strut/shock absorber check1 Park the vehicle on level ground, turn theengine off and apply the handbrake. Checkthe tyre pressures.2 Push down at one corner of the vehicle,then release it while noting the movement ofthe body. It should stop moving and come torest in a level position with one or twobounces.3 If the vehicle continues to move up anddown, or if it fails to return to its originalposition, a worn or weak strut or shockabsorber is probably the reason.4 Repeat the above check at each of thethree remaining corners of the vehicle.5 Raise the vehicle and support it on axlestands.6 Check the struts/shock absorbers forevidence of fluid leakage. A light film of fluid is

1•21

22.4 Hoses, like drivebelts, have a habit offailing at the worst possible time - toprevent the inconvenience of a blownradiator or heater hose, inspect them

carefully as shown here

23.2 Check the exhaust system rubbermountings for cracks

1

Every 12 000 miles

no cause for concern. Make sure that any fluidnoted is from the struts/shocks, and not fromany other source. If leakage is noted, renewthe struts or shock absorbers in axle pairs (oras a full set).7 Check the struts/shock absorbers to besure that they are securely mounted andundamaged. Check the upper mountings fordamage and wear. If damage or wear isnoted, renew the struts or shock absorbers.8 If the struts or shock absorbers must berenewed, refer to Chapter 10 for theprocedure. Always renew both units on thesame axle, or the safety of the vehicle may becompromised. If possible, renew all four as aset.

Steering and suspension check9 Inspect the steering system componentsfor damage and distortion. Look for leaks anddamaged seals, boots and fittings.10 Clean the lower end of the steeringknuckle. Have an assistant grasp the loweredge of the tyre and move the wheel in andout, while you look for movement at thesteering knuckle-to-axle arm balljoints.Inspect the balljoint boots for tears (seeillustration). If there is any movement, or theboots are torn or leaking, the balljoint(s) mustbe renewed.11 Grasp each front tyre at the front and rearedges, push in at the front, pull out at the rearand feel for play in the steering linkage. If anyfree play is noted, check the steering gearmountings and the track rod balljoints forlooseness. If the steering gear mountings areloose, tighten them. If the track rods areloose, the balljoints may be worn (check tomake sure the nuts are tight). Additionalsteering and suspension system informationcan be found in Chapter 10.

25 Driveshaft gaiter check 11 The driveshaft gaiters are very importantbecause they prevent dirt, water and foreignmaterial from entering and damaging theconstant velocity (CV) joints. External oil andgrease contamination can cause the gaiter

material to deteriorate prematurely, so it’s agood idea to wash the gaiters with soap andwater.2 Inspect the gaiters for tears and cracks, aswell as for loose clamps (see illustration). Ifthere is any evidence of cracks or leakinglubricant, the gaiter must be renewed (seeChapter 8).

26 Brake system check 2Warning: Dust produced by liningwear and deposited on brakecomponents may containasbestos, which is hazardous to

your health. Do not blow it out withcompressed air, and don’t inhale it! Do notuse petroleum-based solvents to removethe dust. Brake system cleaner ormethylated spirit should be used to flushthe dust into a drain pan. After the brakecomponents are wiped with a damp rag,dispose of the contaminated rag(s) and thedrain pan contents into a covered andlabelled container. Try to use asbestos-free new parts whenever possible.Note: In addition to the specified intervals, thebrake system should be inspected each timethe wheels are removed or a malfunction isindicated. Because of the obvious safety con-siderations, the following brake system checksare some of the most important maintenanceprocedures you can perform on your vehicle.

Symptoms of brake systemproblems1 The disc brakes have built-in electrical wearindicators which cause a warning light on thedash to come on when they’re worn to therenewal point. When the light comes on,renew the pads immediately, or expensivedamage to the brake discs could result.2 Any of the following symptoms couldindicate a potential brake system defect:a) Vehicle pulls to one side when the brake

pedal is depressedb) Brakes make squealing or dragging noises

when appliedc) Brake pedal travel excessive

d) Brake pedal pulsates (normal if ABS isworking)

e) Brake fluid leaks (usually on the inner sideof the tyre or wheel)

3 If any of these conditions are noted, inspectthe brake system immediately.

Brake lines and hosesNote: Steel brake pipes are used throughoutthe brake system, with the exception offlexible, reinforced hoses at the front wheelsand as connectors at the rear axle. Periodicinspection of all these lines is very important.4 Park the vehicle on level ground, andswitch off the engine. Remove the wheelcovers. Loosen, but do not remove, the boltson all four wheels.5 Raise the vehicle and support it securely onaxle stands.6 Remove the wheels (see “Jacking andtowing” at the front of this book, or refer toyour owner’s handbook, if necessary).7 Check all brake lines and hoses for cracks,chafing of the outer cover, leaks, blisters, anddistortion. Check the brake hoses at front andrear of the vehicle for softening, cracks,bulging, or wear from rubbing on othercomponents. Check all threaded fittings forleaks, and make sure the brake hosemounting bolts and clips are secure.8 If leaks or damage are discovered, theymust be repaired immediately. Refer toChapter 9 for detailed brake system repairprocedures.

Disc brakes9 If it hasn’t already been done, raise thevehicle and support it securely on axle stands.Remove the front wheels.10 The disc brake calipers, containing thepads, are now visible. Each caliper has anouter and an inner pad - all pads should bechecked.11 Note the pad thickness by lookingthrough the inspection hole in the caliper (seeillustration). If the lining material is 2.0 mmthick or less, or if it is tapered from end toend, the pads should be renewed (seeChapter 9). Keep in mind that the lining

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26.11 Look through the caliper inspectionwindow to inspect the brake pads - the

pad lining which rubs against the disc canalso be inspected by looking through each

end of the caliper

25.2 Gently probe the driveshaft boots tocheck for cracks

24.10 Inspect the balljoint boots for tears(arrowed)

Every 12 000 miles

material is bonded to a metal plate or shoe -the metal portion is not included in thismeasurement. Always renew the pads onboth sides of the vehicle (in axle sets), even ifonly one pad of the four is worn, or unevenbraking may result.12 Remove the calipers withoutdisconnecting the brake hoses (see Chap-ter 9).13 Check the condition of the brake disc.Look for score marks, deep scratches andoverheated areas (they will appear blue ordiscoloured). If damage or wear is noted, thedisc can be removed and resurfaced by anengineering workshop; otherwise, it will haveto be renewed. In either case, both discsshould be involved, even if only one is worn.Refer to Chapter 9 for more detailedinspection and repair procedures.

Drum brakes14 Refer to Chapter 9 and remove the rearbrake drums.15 Note the thickness of the lining materialon the rear brake shoes, and look for signs ofcontamination by brake fluid or grease (seeillustration). If the material is within 2.0 mm ofthe recessed rivets or metal shoes, renew thebrake shoes. The shoes should also berenewed if they are cracked, glazed (shinylining surfaces), or contaminated with brakefluid or grease. See Chapter 9 for the renewalprocedure.16 Check the shoe return and hold-downsprings and the adjusting mechanism. Makesure all these components are fitted correctly,

and are in good condition. Deteriorated ordistorted springs, if not renewed, could allowthe linings to drag and wear prematurely.17 Check the wheel cylinders for leakage bycarefully peeling back the rubber boots. Slightmoisture behind the boots is acceptable. Ifbrake fluid is noted behind the boots or if itruns out of the wheel cylinder, the wheelcylinders must be overhauled or renewed (seeChapter 9).18 Check the drums for cracks, score marks,deep scratches and high spots, which willappear as small discoloured areas. Ifimperfections cannot be removed with emerycloth, both drums must be resurfaced by aspecialist (see Chapter 9 for more detailedinformation).19 Refer to Chapter 9 and fit the brakedrums.20 Refit the wheels, but don’t lower thevehicle yet.

Handbrake21 The easiest, and perhaps most obvious,method of checking the handbrake is to parkthe vehicle on a steep hill with the handbrakeapplied and the transmission in Neutral (stayin the vehicle while performing this check). Ifthe handbrake doesn’t prevent the vehiclefrom rolling, refer to Chapter 9 and adjust it.

27 Wiper blades -check and renewal 1

1 Road film can build up on the wiper bladesand affect their efficiency, so they should be

washed regularly with a mild detergentsolution.

Check2 The wiper and blade assembly should beinspected periodically. If inspection revealshardened or cracked rubber, renew the wiperblades. If inspection reveals nothing unusual,wet the windscreen, turn the wipers on, allowthem to cycle several times, then switch themoff. An uneven wiper pattern across the glass,or streaks over clean glass, indicate that theblades should be renewed.3 The operation of the wiper mechanism canloosen the retaining nuts, so they should bechecked and tightened, as necessary, at thesame time the wiper blades are checked (seeChapter 12 for further information regardingthe wiper mechanism).

Wiper blade renewal4 Pull the wiper/blade assembly away fromthe glass.5 Press the retaining tab in, and slide theblade assembly down the wiper arm (seeillustration).6 If you wish to renew the blade rubbersseparately, detach the end of the rubber fromthe wiper blade frame, then slide the rubberout of the frame (see illustration).7 Compare the new rubber with the old forlength, design, etc.8 Slide the new rubber into place, and insertthe end in the wiper blade frame to lock it inplace.9 Refit the blade assembly on the arm, thenwet the glass and check for proper operation.

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27.6 Detach the end of the wiper elementfrom the end of the frame, then slide the

element out

27.5 Press the retaining tab in, then slidethe wiper blade assembly down and out of

the hook in the end of the wiper arm

26.15 If the lining is bonded to the brakeshoe, measure the lining thickness fromthe outer surface to the metal shoe, asshown here (A); if the lining is riveted tothe shoe, measure from the lining outer

surface to the rivet head

1

Every 12 000 miles

Every 24 000 miles or 2 years, whichever comes first

28 Automatic transmission fluidand filter change 1

1 At the specified intervals, the transmissionfluid should be drained and renewed. Sincethe fluid will remain hot long after driving,

perform this procedure only after the enginehas cooled down completely.2 Before beginning work, purchase thespecified transmission fluid (see “Lubricantsand fluids” at the beginning of this Chapter)and a new filter.3 Other tools necessary for this job include axlestands or ramps to support the vehicle in a

raised position, a drain pan capable of holding atleast 4.5 litres, and newspapers and clean rags.4 Raise the vehicle and support it securely.5 Loosen the dipstick tube collar, then detachthe dipstick tube and let the fluid drain (seeillustrations).6 Remove the transmission sump mountingbolts and brackets (see illustration).

7 Detach the sump from the transmission andlower it, being careful not to spill theremaining fluid (see illustration).8 Carefully clean the sump-to-transmissioncontact surface.9 Pour the fluid from the sump into a suitablecontainer, then clean the sump with solventand dry it with compressed air. Be sure toclean any metal filings from the magnet, ifapplicable.10 Remove the filter from inside thetransmission (see illustrations).11 Fit the O-ring and a new filter, being sureto tighten the bolts securely.12 Make sure that the sump gasket contactsurfaces are clean, then fit the new gasket.Offer the sump up to the transmission, andrefit the brackets and bolts. Working around

the sump, tighten each bolt a little at a timeuntil the torque listed in this Chapter’s Specifi-cations is reached. Don’t overtighten thebolts! Connect the dipstick tube, and tightenthe collar securely.13 Lower the vehicle, and add the specifiedamount of fluid through the filler tube (seeSection 8).14 With the transmission in Park and thehandbrake applied, run the engine at fast idle,but don’t race it.15 Move the gear selector through eachposition, and back to Park. Check the fluidlevel.16 Check under the vehicle for leaks after thefirst few trips.

29 Cooling system - draining,flushing and refilling 1

Warning: Do not allow antifreezeto come in contact with your skin,or with the painted surfaces of thevehicle. Rinse off spills

immediately with plenty of water. Antifreezeis highly toxic if ingested. Never leaveantifreeze lying around in an open containeror in puddles on the floor; children and petsare attracted by its sweet smell, and maydrink it. Check with local authorities aboutdisposing of used antifreeze. Localcollection centres may exist to see thatantifreeze is disposed of safely.

1 Periodically, the cooling system should bedrained, flushed and refilled. This will restorethe effectiveness of the antifreeze mixture andprevent formation of rust and corrosion, whichcan impair the performance of the coolingsystem and cause engine damage. When thecooling system is serviced, all hoses and theradiator cap should be checked and renewedif necessary.

Draining2 If the vehicle has just been driven, waitseveral hours to allow the engine to cool downbefore beginning this procedure.3 Once the engine is completely cool, removethe expansion tank cap or radiator cap. If thecap must be removed while the engine is stillwarm, unscrew it slowly, and take adequateprecautions to avoid scalding.4 Move a large container under the radiator tocatch the coolant. Where a drain plug is fitted,unscrew it (a pair of pliers or screwdriver maybe required to turn it, depending on themodel) (see illustration). Where there is nodrain plug, it will be necessary to disconnectthe bottom hose from the radiator.5 While the coolant is draining, check thecondition of the radiator hoses, heater hosesand clamps (see Section 21 if necessary).6 Renew any damaged clamps or hoses (seeChapter 3 for detailed renewal procedures).

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28.10c Remove the O-ring from thetransmission. If it is in good condition,clean it and transfer it to the new fluid

filter; otherwise, renew it28.10b . . . then remove the fluid filter from

the transmission28.10a Use a Torx key to remove the filter

bolts . . .

28.7 Lower the sump from thetransmission

28.6 Use a socket and extension toremove the bolts and brackets

28.5b Detach the tube and let the fluiddrain

28.5a Unscrew the dipstick tube collar

Every 24 000 miles

Flushing7 Once the system is completely drained,flush the radiator with fresh water from agarden hose until the water runs clear at thedrain or bottom hose. If the radiator isseverely corroded, damaged or leaking, itshould be removed (see Chapter 3) and takento a radiator repair specialist.8 Flushing in this way will remove sedimentsfrom the radiator, but will not remove rust andscale from the engine and cooling tubesurfaces. These deposits can be removed byusing a chemical cleaner. Follow theprocedure outlined in the cleanermanufacturer’s instructions. Remove thecylinder block drain plug before flushing theengine.9 On models so equipped, remove theoverflow hose from the coolant recoveryreservoir. Drain the reservoir and flush it withclean water, then reconnect the hose.

Refilling10 Tighten the radiator drain plug, orreconnect the radiator bottom hose. Refit andtighten the cylinder block drain plug.

Four-cylinder engines11 Slowly add new coolant (a 40%/60%mixture of antifreeze to water) to the radiatoruntil it is full. Add coolant to the reservoir upto the lower mark.12 Leave the radiator cap off, and run theengine in a well-ventilated area until thethermostat opens (coolant will begin flowingthrough the radiator, and the upper radiatorhose will become hot).13 Turn the engine off, and let it cool. Addmore coolant mixture to bring the coolantlevel back up to the lip on the radiator fillerneck. On the M40 engine, unscrew the bleedscrew from the top of the radiator, and addcoolant until it comes out of the bleed screwhole. Refit and tighten the bleed screw.14 Squeeze the upper radiator hose to expelair, then add more coolant mixture ifnecessary. Refit the radiator cap.15 Start the engine, allow it to reach normaloperating temperature, and check for leaks.

Six-cylinder engines16 Loosen the bleed screw in the thermostathousing (see illustration)17 Fill the radiator with a 40%/60% solutionof antifreeze and water until it comes out ofthe bleed screw opening. Tighten the bleedscrew.18 Refit the radiator cap, and run the engineuntil the thermostat opens (the upper radiatorhose will become hot). Slowly loosen thebleed screw until no bubbles emerge, thentighten the screw.19 Repeat the procedure until the air is bledfrom the system.

30 Fuel filter renewal 1Warning: Fuel is extremelyflammable, so take extraprecautions when you work onany part of the fuel system. Don’t

smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you performany kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.1 On fuel injection engines, depressurise thefuel system (see Chapter 4).2 The fuel filter is located in the enginecompartment on the bulkhead, or under thevehicle adjacent to the fuel tank.3 Because on some models the filter islocated adjacent to the starter motor, fuelcould leak onto the electrical connections. Forsafety reasons, therefore, disconnect thebattery negative cable before beginning work.


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.4 Place a pan or rags under the fuel filter tocatch any spilled fuel. If suitable hose clampsare available, clamp the inlet and outlet hoses.5 Detach the hoses and remove the bracketscrews/nuts, then remove the filter and whereapplicable the bracket assembly (seeillustration).6 Detach the filter from the bracket.7 Refitting is the reverse of removal. Be surethe arrow on the filter points in the direction offuel flow.

31 Manual transmissionlubricant change 1

1 Tools necessary for this job include axlestands to support the vehicle in a raisedposition, an Allen key to remove the drainplug, a drain pan, newspapers and clean rags.The correct amount of the specified lubricantshould also be available (see “Lubricants andfluids” at the start of this Chapter).2 The lubricant should be drained when it ishot (ie immediately after the vehicle has beendriven); this will remove any contaminantsbetter than if the lubricant were cold. Because

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30.5 To renew the fuel filter, disconnectthe hoses (A), then unscrew the nut (B) and

detach the filter from the bracket (fuelinjection type shown)

29.16 The bleed screw (arrowed) islocated on the thermostat housing (six-

cylinder models)

29.4 Radiator drain plug location(arrowed) - not fitted to all models

31.5 Use an Allen key to remove the drainplug (arrowed) from the bottom of the

transmission

1

Every 24 000 miles

the lubricant will be hot, it would be wise towear rubber gloves.3 Raise the vehicle and place it on axlestands. Make sure it is safely supported, andas level as possible.4 Move the necessary equipment under thevehicle, being careful not to touch any of thehot exhaust components.5 Place the drain pan under the transmission,and remove the filler/level plug from the sideof the transmission. Loosen the drain plug(see illustration).6 Carefully remove the drain plug. Be carefulnot to burn yourself on the lubricant.7 Allow the lubricant to drain completely.Clean the drain plug thoroughly, then refit andtighten it securely.8 Refer to Section 16 and fill the transmissionwith new lubricant, then refit the filler/levelplug, tightening it securely.9 Lower the vehicle. Check for leaks at thedrain plug after the first few miles of driving.

32 Differential lubricant change 11 Drive the vehicle for several miles to warmup the differential lubricant, then raise thevehicle and support it securely on axle stands.2 Move a drain pan, rags, newspapers and anAllen key under the vehicle. Since thelubricant will be hot, wear rubber gloves toprevent burns.3 Remove the filler/level plug from thedifferential; this is the upper of the two plugs.4 With the drain pan under the differential,loosen the drain plug; this is the lower of thetwo plugs (see illustration).5 Carefully unscrew the drain plug until youcan remove it from the case.6 Allow all the oil to drain into the pan, thenrefit the drain plug and tighten it securely.7 Refer to Section 17 and fill the differentialwith lubricant.8 Refit the filler/level plug and tighten itsecurely.9 Lower the vehicle. Check for leaks at thedrain plug after the first few miles of driving.

33 Evaporative emissionscontrol (EVAP) system check 1

1 The function of the evaporative emissionscontrol system is to draw fuel vapours fromthe tank and fuel system, store them in acharcoal canister, and then burn them duringnormal engine operation. This system isnormally only fitted to those vehiclesequipped with a catalytic converter.2 The most common symptom of a fault inthe evaporative emissions system is a strongfuel odour in the engine compartment. If a fuelodour is detected, inspect the charcoalcanister and system hoses for cracks. Thecanister is located in the front corner of theengine compartment on most models (seeillustration).3 Refer to Chapter 6 for more information onthe evaporative emissions system.

34 Service indicator lightresetting 4

Service indicator lights1 All models covered in this manual areequipped with various service indicator lightson the facia, which automatically go on whenthe mileage interval is reached. These lightscan only be turned off by using a special toolwhich plugs into the service connectorlocated in the engine compartment.2 Although the service light resetting tool canbe obtained from a dealer, reasonably-pricedalternatives may also be available fromaftermarket sources. When obtaining a tool, itis important to know the vehicle year andmodel, and whether the service connector has15 or 20 pins (see illustrations). Once theproper tool is obtained, it is a simple matter toplug it into the service connector and,following the tool manufacturer’s instructions,reset the service lights. Note: The brakewarning light will not automatically reset if thesensor on the brake pad (or its wiring) is

damaged because it is worn through: it mustbe repaired first.3 The service lights are controlled by theService Indicator (SI) board in the instrumentcluster, which is powered by rechargeablebatteries. Should these batteries fail,problems will develop in the SI board.Symptoms of failed batteries include theinability to reset the service lights andmalfunctions affecting the tachometer,temperature gauge and radio operation. Referto Chapter 12 for more information on the SIboard.

Every 60 000 miles

35 Engine timing belt renewal 5Note: This is not included in themanufacturer’s maintenance schedule, but isstrongly recommended as a precautionagainst the timing belt failing in service. If thetiming belt fails while the engine is running,extensive engine damage could be caused.

Refer to Chapter 2A, Section 10.

1•26

34.2b An aftermarket service lightresetting tool such as this one can be

plugged into the service connector andused to reset the service lights

34.2a The earlier 15-pin connector(arrowed) is mounted near the front of theengine. The 20-pin connector used on latermodels is located in the left rear corner of

the engine compartment

33.2 Inspect the hoses (arrowed) at thetop of the evaporative emissions charcoal

canister for damage

32.4 Remove the differential drain plugwith an Allen key

Every 24 000 miles

2A

GeneralDisplacement

3-series, E30 body style316i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1596 cc (M40/4-cylinder engine)316 (1983 to 1988) and 318i (1983 to 1987) . . . . . . . . . . . . . . . . 1766 cc (M10/4-cylinder engine)318i (1987 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1796 cc (M40/4-cylinder engine)320i (1987 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1990 cc (M20/6-cylinder engine)325i (1987 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M20/6-cylinder engine)

5-series, E28 body style (“old-shape”)518 (1981 to 1985) and 518i (1985 to 1988) . . . . . . . . . . . . . . . . 1766 cc (M10/4-cylinder engine)525i (1981 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M30/6-cylinder engine)528i (1981 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2788 cc (M30/6-cylinder engine)535i (1985 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)M535i (1985 to 1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)

5-series, E34 body style (“new-shape”)518i (1990 to 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1796 cc (M40/4-cylinder engine)520i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1990 cc (M20/6-cylinder engine)525i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2494 cc (M20/6-cylinder engine)530i (1988 to 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2986 cc (M30/6-cylinder engine)535i (1988 to 1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3430 cc (M30/6-cylinder engine)

Firing orderFour-cylinder engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3-4-2Six-cylinder engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5-3-6-2-4

Lubrication systemOil pressure (all engines)

At idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 to 2.0 barsRunning (for example, at 4000 rpm) . . . . . . . . . . . . . . . . . . . . . . . . . . 4 bars or above (typically)

Oil pump rotor clearance - M40 engine(body-to-outer rotor/outer rotor-to-inner rotor) . . . . . . . . . . . . . . . . . . . 0.12 mm to 0.20 mmOil pump pressure relief valve spring length - M40 engine . . . . . . . . . . 84.1 mm

Chapter 2 Part A:In-car engine repair procedures

Camshaft - removal, inspection and refitting . . . . . . See Chapter 2BCompression check . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2BCrankshaft rear oil seal - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Cylinder head - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 12Cylinder head - dismantling and inspection . . . . . . . See Chapter 2BDrivebelt check, adjustment and renewal . . . . . . . . See Chapter 1Engine - removal and refitting . . . . . . . . . . . . . . . . . See Chapter 2BEngine mountings - check and renewal . . . . . . . . . . . . . . . . . . . . . . 17Engine oil and filter change . . . . . . . . . . . . . . . . . . . See Chapter 1Engine overhaul - general information . . . . . . . . . . . See Chapter 2BExhaust manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . 6Flywheel/driveplate - removal and refitting . . . . . . . . . . . . . . . . . . . 15Front oil seals - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Intake manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 5

Oil pump - removal, inspection and refitting . . . . . . . . . . . . . . . . . . 14Repair operations possible with the engine in the vehicle . . . . . . . . 2Rocker arm and shaft assembly - dismantling, inspection

and reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2BSpark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Sump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Timing belt and sprockets - removal, inspection and refitting . . . . . 10Timing belt covers - removal and refitting . . . . . . . . . . . . . . . . . . . . . 9Timing chain and sprockets - removal, inspection and refitting . . . . 8Timing chain covers - removal and refitting . . . . . . . . . . . . . . . . . . . 7Top Dead Centre (TDC) for No 1 piston - locating . . . . . . . . . . . . . . 3Valve clearance check and adjustment . . . . . . . . . . . See Chapter 1Valve cover - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 4Valves - servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 2B

2A•1







Specifications

Contents

Torque wrench settings NmTiming chain tensioner plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Timing belt tensioner bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Camshaft sprocket-to-camshaft bolt

M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10M20 and M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Flange to camshaft (M30 engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Timing chain or belt covers-to-engineM6 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10M8 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22M10 (bolt size) bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Crankshaft pulley bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Crankshaft hub bolt or nut

M10 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190M20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410M30 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440M40 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

Cylinder head bolts*M10 four-cylinder engine

Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Stage 2 (wait 15 minutes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 33°Stage 3 (engine at normal operating temperature) . . . . . . . . . . . . . Angle-tighten an additional 25°

M20 six-cylinder engine with hex-head boltsStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Stage 2 (wait 15 minutes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Stage 3 (engine at normal operating temperature) . . . . . . . . . . . . . Angle-tighten an additional 25°

M20 six-cylinder engine with Torx-head boltsStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 90°Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 90°

M30 six-cylinder engine (up to and including 1987 model year)Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Stage 2 (wait 15 minutes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 33°Stage 3 (engine at normal operating temperature) . . . . . . . . . . . . . Angle-tighten an additional 33°

M30 six-cylinder engine (from 1988 model year)Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Stage 2 (wait 20 minutes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Stage 3 (engine at normal operating temperature) . . . . . . . . . . . . . Angle-tighten an additional 35°

M40 four-cylinder engineStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 90°Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 90°

Intake manifold-to-cylinder head boltsM8 bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22M7 bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15M6 bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Exhaust manifold-to-cylinder head nutsM6 nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10M7 nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Flywheel/driveplate boltsManual transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105Automatic transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Intermediate shaft sprocket bolt (M20 engines) . . . . . . . . . . . . . . . . . . . 60Sump-to-block bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 to 11Oil pump bolts (except M40 engines) . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Oil pump sprocket bolts (M10 and M30 engines) . . . . . . . . . . . . . . . . . 10Oil pump cover plate-to-engine front end cover (M40 engines) . . . . . . . 9Front end cover-to-engine bolts (M20 and M40 engines)

M6 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10M8 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Crankshaft rear oil seal retainer-to-block boltsM6 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9M8 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

* BMW recommend that the cylinder head bolts are renewed as a matter of course.

2A•2 In-car engine repair procedures

1 General information

This Part of Chapter 2 is devoted to in-vehicle engine repair procedures. Allinformation concerning engine removal andrefitting and engine block and cylinder headoverhaul can be found in Chapter 2B.

The following repair procedures are basedon the assumption that the engine is still fittedin the vehicle. If the engine has been removedfrom the vehicle and mounted on a stand,many of the steps outlined in this Part ofChapter 2 will not apply.

The Specifications included in this Part ofChapter 2 apply only to the procedurescontained in this Part. Chapter 2B containsthe Specifications necessary for cylinder headand engine block rebuilding.

The single overhead camshaft four- andsix-cylinder engines covered in this manualare very similar in design. Where there aredifferences, they will be pointed out.

The means by which the overheadcamshaft is driven varies according to enginetype; M10 and M30 engines use a timingchain, while M20 and M40 engines have atiming belt.

2 Repair operations possiblewith the engine in the vehicle

Many major repair operations can beaccomplished without removing the enginefrom the vehicle.

Clean the engine compartment and theexterior of the engine with some type ofdegreaser before any work is done. It willmake the job easier, and help keep dirt out ofthe internal areas of the engine.

Depending on the components involved, itmay be helpful to remove the bonnet toimprove access to the engine as repairs areperformed (see Chapter 11 if necessary).Cover the wings to prevent damage to thepaint. Special pads are available, but an oldbedspread or blanket will also work.

If vacuum, exhaust, oil or coolant leaksdevelop, indicating a need for gasket or sealrenewal, the repairs can generally be madewith the engine in the vehicle. The intake andexhaust manifold gaskets, sump gasket,crankshaft oil seals and cylinder head gasketare all accessible with the engine in place.

Exterior components, such as the intakeand exhaust manifolds, the sump, the oilpump, the water pump, the starter motor, thealternator, the distributor and the fuel systemcomponents, can be removed for repair withthe engine in place.

The cylinder head can be removed withoutremoving the engine, so this procedure iscovered in this Part of Chapter 2. Camshaft,rocker arm and valve component servicing is

most easily accomplished with the cylinderhead removed; these procedures are coveredin Part B of this Chapter. Note, however, thatthe camshaft on the M40 engine may beremoved with the engine in the vehicle since itis retained by bearing caps.

In extreme cases caused by a lack ofnecessary equipment, repair or renewal ofpiston rings, pistons, connecting rods andbig-end bearings is possible with the engine inthe vehicle. However, this practice is notrecommended, because of the cleaning andpreparation work that must be done to thecomponents involved.

3 Top Dead Centre (TDC) forNo 1 piston - locating 2

Note 1: The following procedure is based onthe assumption that the distributor (ifapplicable) is correctly fitted. If you are tryingto locate TDC to refit the distributor correctly,piston position must be determined by feelingfor compression at the No 1 spark plug hole,then aligning the ignition timing marks orinserting the timing tool in the flywheel, asapplicable.Note 2: The No 1 cylinder is the one closest tothe radiator.1 Top Dead Centre (TDC) is the highest pointin the cylinder that each piston reaches as ittravels up and down when the crankshaftturns. Each piston reaches TDC on thecompression stroke and again on the exhauststroke, but TDC generally refers to pistonposition on the compression stroke.2 Positioning the piston at TDC is an essentialpart of many procedures, such as timing beltor chain removal and distributor removal. 3 Before beginning this procedure, be sure toplace the transmission in Neutral, and applythe handbrake or chock the rear wheels. Also,disable the ignition system by detaching thecoil wire from the centre terminal of thedistributor cap, and earthing it on the engineblock with a jumper wire. Remove the sparkplugs (see Chapter 1).4 In order to bring any piston to TDC, thecrankshaft must be turned using one of themethods outlined below. When looking at thefront of the engine, normal crankshaft rotationis clockwise.(a) The preferred method is to turn the

crankshaft with a socket and ratchetattached to the bolt threaded into thefront of the crankshaft.

(b) A remote starter switch, which may savesome time, can also be used. Follow theinstructions included with the switch.Once the piston is close to TDC, use asocket and ratchet as described in theprevious paragraph.

(c) If an assistant is available to turn theignition switch to the Start position inshort bursts, you can get the piston closeto TDC without a remote starter switch.

Make sure your assistant is out of thevehicle, away from the ignition switch,then use a socket and ratchet asdescribed in (a) to complete theprocedure.

5 Note the position of the terminal for the No 1 spark plug lead on the distributor cap. Ifthe terminal isn’t marked, follow the plug leadfrom the No 1 cylinder spark plug to the cap(No 1 cylinder is nearest the radiator).6 Use a felt-tip pen or chalk to make a markdirectly below the No 1 terminal on thedistributor body or timing cover.7 Detach the distributor cap, and set it aside(see Chapter 1 if necessary).8 Turn the crankshaft (see paragraph 4above) until the timing marks (located at thefront of the engine) are aligned (seeillustration). The M40 engine does not haveany timing marks at the front of the engine,but instead has a timing hole in the flywheelwhich must be aligned with a hole in the rearflange of the cylinder block. On this engine,turn the crankshaft until the distributor rotor isapproaching the No 1 TDC position, thencontinue to turn the crankshaft until a suitableclose-fitting drill can be inserted through thehole in the cylinder block and into theflywheel.9 Look at the distributor rotor - it should bepointing directly at the mark you made on thedistributor body or timing cover.10 If the rotor is 180 degrees out, the No 1piston is at TDC on the exhaust stroke.11 To get the piston to TDC on thecompression stroke, turn the crankshaft onecomplete turn (360°) clockwise. The rotorshould now be pointing at the mark on thedistributor or timing cover. When the rotor ispointing at the No 1 spark plug lead terminalin the distributor cap and the ignition timingmarks are aligned, the No 1 piston is at TDCon the compression stroke. Note: If it’simpossible to align the ignition timing markswhen the rotor is pointing at the mark, thetiming belt or chain may have jumped theteeth on the sprockets, or may have beenfitted incorrectly.

In-car engine repair procedures 2A•3

3.8 Align the notch in the pulley with thenotch on the timing plate, then check to

see if the distributor rotor is pointing to theNo 1 cylinder (if not, the camshaft is 180degrees out - the crankshaft will have to

be rotated 360 degrees)

2A

12 After the No 1 piston has been positionedat TDC on the compression stroke, TDC forany of the remaining pistons can be locatedby turning the crankshaft and following thefiring order. Mark the remaining spark pluglead terminal locations just like you did for theNo 1 terminal, then number the marks tocorrespond with the cylinder numbers. As youturn the crankshaft, the rotor will also turn.When it’s pointing directly at one of the markson the distributor, the piston for that particularcylinder is at TDC on the compression stroke.

4 Valve cover - removal and refitting 1

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation codebefore disconnecting the battery.

Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

Removal1 Disconnect the battery negative cable.2 Detach the breather hose from the valvecover.3 On M20 engines, unbolt and remove theintake manifold support bracket and, ifapplicable, the bracket for the engine sensorsor idle air stabiliser (it will probably benecessary to disconnect the electricalconnectors from the sensors and stabiliser).4 On M30 engines, disconnect the electricalconnector for the airflow sensor. Unclip theelectrical harness, moving it out of the way.5 Where necessary on M30 engines, removethe hoses and fittings from the intake air hose,then loosen the clamp and separate the hosefrom the throttle body. Unscrew the mountingnuts for the air cleaner housing, and removethe housing together with the air hose andairflow sensor.6 Remove the valve cover retaining nuts andwashers (see illustrations). Where necessary,disconnect the spark plug lead clip or cover

from the stud(s), and set it aside. It will usuallynot be necessary to disconnect the leads fromthe spark plugs.7 Remove the valve cover and gasket.Discard the old gasket. On the M40 engine,also remove the camshaft cover (seeillustrations). If applicable, remove the semi-circular rubber seal from the cut-out at thefront of the cylinder head.

Refitting8 Using a scraper, remove all traces of oldgasket material from the sealing surfaces ofthe valve cover and cylinder head.

Caution: Be very careful not toscratch or gouge the delicatealuminium surfaces. Gasketremoval solvents are available at

motor factors, and may prove helpful.After all gasket material has beenremoved, the gasket surfaces can bedegreased by wiping them with a ragdampened with a suitable solvent.9 If applicable, place a new semi-circularrubber seal in the cut-out at the front of thecylinder head, then apply RTV-type gasketsealant to the joints between the seal and themating surface for the valve cover gasket.Note: After the sealant is applied, you shouldrefit the valve cover and tighten the nuts withinten minutes.10 Refit the camshaft cover (M40 engine), thevalve cover and a new gasket. Refit thewashers and nuts; tighten the nuts evenly andsecurely. Don’t overtighten these nuts - they

should be tight enough to prevent oil fromleaking past the gasket, but not so tight thatthey warp the valve cover.11 The remainder of refitting is the reverse ofremoval.

5 Intake manifold - removal and refitting 2

Removal1 Allow the engine to cool completely, thenrelieve the fuel pressure on fuel-injectionengines (see Chapter 4).2 Disconnect the battery negative cable.


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.3 Drain the engine coolant (see Chapter 1)below the level of the intake manifold. If thecoolant is in good condition, it can be savedand reused.4 On fuel injection engines, loosen the hoseclamp and disconnect the large air inlet hosefrom the throttle body. It may also benecessary to remove the entire aircleaner/inlet hose assembly to provideenough working room (see Chapter 4).


4.7b Removing the camshaft cover on theM40 engine

4.7a Removing the valve cover on the M40 engine

4.7c Removing the valve cover gasket onthe M40 engine

4.6b Valve cover bolt locations (arrowed)on M20 six-cylinder engines

4.6a Valve cover bolt locations (arrowed)on M10 four-cylinder engines

5 On carburettor engines, remove thecomplete air cleaner assembly (see Chap-ter 4).6 Disconnect the coolant hoses from thethrottle body/intake manifold as applicable.7 Disconnect the throttle cable and, ifapplicable, cruise control cable (see Chap-ter 4).8 Remove the EGR valve and line whereapplicable (see Chapter 6).9 At this stage on the M40 engine, the upperpart of the intake manifold should be removedby unscrewing the bolts and nuts. Removethe gaskets (see illustrations).10 On fuel injection engines, disconnect thevacuum hose from the fuel pressure regulator,and disconnect the electrical connectors fromthe fuel injectors (see Chapter 4).11 Disconnect the fuel lines from the fuel railor carburettor, as applicable (see Chapter 4). 12 On the M40 engine, unbolt and removethe support bracket from the bottom of theintake manifold (see illustration).13 Disconnect all remaining hoses and wiresattached between the intake manifold/throttlebody assembly and the engine or chassis.14 Remove the bolts and/or nuts that attachthe manifold to the cylinder head (seeillustrations). Start at the ends and worktoward the middle, loosening each one a littleat a time until they can be removed by hand.Support the manifold while removing thefasteners so it doesn’t fall. Note: You canremove the manifold without removing thethrottle body, injectors, vacuum/thermo

valves, fuel pressure regulator or carburettor.If you’re fitting a new manifold, transfer thecomponents (see Chapter 4) and lines to thenew manifold before it is fitted on the cylinderhead.15 Move the manifold up and down to breakthe gasket seal, then lift it away from the headand remove the gasket (see illustrations).

Refitting16 Remove the old gasket, then carefullyscrape all traces of sealant off the head andthe manifold mating surfaces. Be very carefulnot to nick or scratch the delicate aluminiummating surfaces. Gasket removal solvents areavailable at motor factors, and may provehelpful. Make sure the surfaces are perfectlyclean and free of dirt and oil.

17 Check the manifold for corrosion (at thecoolant passages), cracks, warping and otherdamage. Cracks and warping normally showup near the gasket surface, around the studholes. If defects are found, have the manifoldrepaired (or renew it, as necessary).18 When refitting the manifold, always use anew gasket. Where one side of the gasket hasa graphite surface, this must face the cylinderhead.19 Refit the nuts and bolts and tighten themgradually, working from the centre out to theends, to the torque listed in this Chapter’sSpecifications.20 The remainder of refitting is the reverse ofremoval. On the M40 engine, renew thegaskets between the upper and lower parts ofthe manifold.


5.9c . . . and gaskets5.9b . . . and remove the upper part of theintake manifold . . .

5.9a On the M40 engine, remove the nutsand special bolts . . .

5.15b Removing the lower intake manifoldgasket (M40 engine)

5.15a Removing the lower intake manifold(M40 engine)

5.14a Remove the intake manifold nutswith a socket, ratchet and long extension

(M20 engine)

5.12 Removing the support bracket fromthe bottom of the intake manifold

(M40 engine)

5.14b Removing the lower intake manifoldnuts (M40 engine)

2A

6 Exhaust manifold - removal and refitting 1

Warning: Make sure the engine iscompletely cool before beginningwork on the exhaust system.Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation codebefore disconnecting the battery.

Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable.2 On models where the air cleaner is on theexhaust manifold side of the engine, removethe air cleaner housing assembly and/orairflow sensor to provide sufficient workingarea (see Chapter 4, if necessary).

3 Unplug the HT leads and set the spark pluglead harness aside (see Chapter 1). 4 Clearly label, then disconnect or remove, allwires, hoses, fittings, etc. that are in the way.Be sure to disconnect the oxygen sensor,where fitted.5 Raise the vehicle, and support it securelyon axle stands. Working from under thevehicle, separate the exhaust downpipe fromthe manifold. Use penetrating oil on thefasteners to ease removal (see illustrations).6 Remove the axle stands, and lower thevehicle. Working from the ends of themanifold toward the centre, loosen theretaining nuts gradually until they can beremoved. Again, penetrating oil may provehelpful.7 Pull the manifold off the head, then removethe old gaskets (see illustrations). Note: Bevery careful not to damage the oxygen sensor,where fitted.

8 Clean the gasket mating surfaces of thehead and manifold, and make sure thethreads on the exhaust manifold studs are ingood condition.9 Check for corrosion, warping, cracks, andother damage. Repair or renew the manifoldas necessary.10 When refitting the manifold, use newgaskets. Tighten the manifold-to-headretaining nuts gradually, starting at the centreand working out to the ends, to the torquelisted in this Chapter’s Specifications. Alsotighten the downpipe-to-manifold nuts.11 The remaining steps are simply a reversalof the removal procedure.

7 Timing chain covers -removal and refitting 5

Note 1: This procedure applies to M10 andM30 engines.Note 2: The upper timing chain cover can beremoved separately. If you need to removeboth the upper and lower covers, special toolsare required. Read paragraphs 8 and 9 beforebeginning work.

Removal1 Disconnect the battery negative cable.

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you

have the correct activation code beforedisconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

2 If you’re removing the lower timing chaincover (the upper cover can be removedseparately), remove the cooling fan and fanshroud, the radiator and the fan drivebeltpulley (see Chapter 3).3 On the M10 engine only, remove the waterpump (see Chapter 3).4 On engines where the distributor cap ismounted directly to the timing chain cover,remove the cap, rotor and the black plasticcover beneath the rotor (see Chapter 1).5 On the M30 engine fitted with the L-Jetronic fuel system, remove the distributor from the upper timing cover (seeChapter 5).6 Remove the valve cover (see Section 4).7 If you’ll be removing the lower timing chaincover on the M30 engine, remove the crankshaftpulley from the vibration damper/hub. Hold thepulley stationary with a socket on the centrebolt, and remove the pulley bolts with anothersocket (see illustration).8 If you’ll be removing the lower timing chain


6.7c Removing the exhaust manifold-to-downpipe gasket (M40 engine)

6.7b Removing the exhaust manifoldgasket (M40 engine)

6.7a Removing the exhaust manifold (M40 engine)

6.5b Exhaust manifold-to-downpipe flange(M40 engine)

6.5a Remove the exhaust manifold nuts(arrowed) from the exhaust pipe (M20

engine) - soaking the nuts with penetratingoil should make them easier to remove

Remove the windscreenwasher reservoir from theright-hand side of the enginecompartment to give moreworking room.

cover, remove the vibration damper/hub bylocking the crankshaft in position andloosening the large centre bolt. Since the boltis on very tight, you’ll need to use anextension bar and socket to break it loose. OnM30 engines, BMW recommends using a 3/4-inch drive socket and extension bar, sincethe bolt is extremely tight on these engines.To lock the crankshaft in place while the boltis being loosened, use BMW special tool No. 11 2 100 (or equivalent).9 On the M10 engine, if the special tool listedin the previous paragraph is not available, youmay try locking the crankshaft by removingthe flywheel/driveplate inspection cover andjamming a wide-bladed screwdriver into thering gear teeth. On the M30 engine, since thebolt is so extremely tight, we don’trecommend substitute methods. Use thecorrect tool. On the M10 engine, after thecentre bolt is removed, it will probably benecessary to use a jaw-type puller to pull thevibration damper off the crankshaft. Positionthe jaws behind the inner pulley groove, andtighten the puller centre bolt very slowly,checking the pulley to make sure it does notget bent or otherwise damaged by the puller.

10 Unscrew the plug and remove the timingchain tensioner spring (see illustration). Thetensioner plunger may come out with thespring. If not, reach down into the hole wherethe tensioner spring was, and remove theplunger. To check the plunger for properoperation, see Section 8.

Caution: The spring is undertension, and this could cause theplug to be ejected from its hole withconsiderable force. Hold thetensioner plug securely as it’s being

unscrewed, and release the spring tensionslowly. 11 On the M30 engine, if you’re removing theupper timing cover, unbolt the thermostat coverand remove the thermostat (see Chapter 3).12 On the M30 engine, if you’re removing thelower timing cover, loosen the alternatormounting bolts, and swing the alternator toone side. Remove the front lower mountingbracket bolt, and loosen the other bolts. Alsounbolt the power steering pump mountingbracket, and move it to one side.13 Remove the bolts and nuts securing theupper timing chain cover to the engine block,and remove the cover. Draw a simple diagramshowing the location of the bolts, so they canbe returned to the same holes from whichthey’re removed. Remove the upper timingchain cover. If it sticks to the engine block, tapit gently with a rubber mallet, or place a pieceof wood against the cover and hit the woodwith a hammer. On the M30 engine fitted withthe L-Jetronic fuel system, remove thedistributor driveshaft.14 Remove the bolts and nuts attaching thelower timing chain cover to the engine block.Be sure to remove the three bolts fromunderneath that connect the front of the sumpto the bottom of the front cover (seeillustration). Loosen the remaining sump bolts.15 Run a sharp, thin knife between the sumpgasket and lower timing chain cover, cuttingthe cover free from the gasket. Be very carefulnot to damage or dirty the gasket, so you canre-use it. 16 Break the lower timing chain cover-to-block gasket seal by tapping the cover with arubber mallet, or with a hammer and block ofwood. Do not prise between the cover and theengine block, as damage to the gasket sealingsurfaces will result.17 Using a scraper, remove all traces of oldgasket material from the sealing surfaces ofthe covers and engine block.

Caution: Be very careful not toscratch or gouge the delicatealuminium surfaces. Also, do notdamage the sump gasket, and

keep it clean. Gasket removal solvents areavailable at motor factors, and may provehelpful. After all gasket material has been

removed, the gasket surfaces can bedegreased by wiping them with a ragdampened with a suitable solvent.

Refitting18 Renew the front oil seals (see Section 11).It’s not wise to take a chance on an old seal,since renewal with the covers removed is veryeasy. Be sure to apply a little oil to the front oilseal lips.19 Apply a film of RTV-type gasket sealant tothe surface of the sump gasket that mateswith the lower timing chain cover. Apply extrabeads of RTV sealant to the edges where thegasket meets the engine block. Note: If thesump gasket is damaged, instead of fitting awhole new gasket, you might try trimming thefront portion of the gasket off at the pointwhere it meets the engine block, then trim offthe front portion of a new sump gasket so it’sexactly the same size. Cover the exposedinside area of the sump with a rag, then cleanall traces of old gasket material off the areawhere the gasket was removed. Attach thenew gasket piece to the sump with contact-cement-type gasket adhesive, then applyRTV-type sealant as described at thebeginning of this paragraph.20 Coat both sides of the new gasket withRTV-type gasket sealant, then attach thelower timing chain cover to the front of theengine. Refit the bolts, and tighten themevenly to the torque listed in this Chapter’sSpecifications. Work from bolt-to-bolt in acriss-cross pattern to be sure they’retightened evenly. Note 1: Tighten the lowercover-to-block bolts first, then tighten thesump-to-cover bolts. If the gasket protrudesabove the cover-to-block joint, or bunches upat the cover-to-sump joint, trim the gasket soit fits correctly. Note 2: After applying RTV-type sealant, reassembly must be completedin about 10 minutes so the RTV won’tprematurely harden.21 Refit the upper timing chain cover in thesame way as the lower cover. If the gasketprotrudes beyond the top of the cover and theengine block, trim off the excess with a razorblade.22 Refitting is otherwise the reverse ofremoval.


7.14 From underneath the vehicle, removethe three bolts (arrowed) that connect the

cover and the sump

7.10 Unscrew the plug from the timingchain cover, and remove the tensioner

spring and plunger

7.7 Place a socket and ratchet on thecentre bolt to keep the pulley stationary,and use another socket and ratchet toremove the smaller bolts attaching the

pulley to the vibration damper

2A

If the pulley seems to besticking on the crankshaft, itmay help to spray the hubarea with some penetrating

oil, and to gently tap on the hub areawith a hammer.

8 Timing chain and sprockets - removal,inspection and refitting

5Note: This procedure applies to M10 and M30engines.

Caution: Once the engine is setat TDC, do not rotate thecamshaft or crankshaft until thetiming chain is reinstalled. If the

crankshaft or camshaft is rotated with thetiming chain removed, the valves could hitthe pistons, causing expensive internalengine damage.

Removal1 Position the No 1 cylinder at Top DeadCentre (TDC) on the compression stroke (seeSection 3).2 Remove the valve cover (see Section 4).Double-check that the No 1 cylinder is at TDCon the compression stroke by making sure theNo 1 cylinder rocker arms are loose (notcompressing their valve springs).3 Remove the upper timing chain cover (seeSection 7). Note the location of the camshafttiming marks, which should now be aligned.On four-cylinder (M10) engines, there’susually a stamped line on the camshaft flangethat aligns with a cast mark on the top of thecylinder head; also, the camshaft sprocketdowel pin hole will be at its lowest point. Onsix-cylinder (M30) engines, a line drawnthrough two of the camshaft sprocket boltsopposite each other would be exactly vertical,while a line drawn through the other two boltswould be horizontal. Additionally, the locatingpin should be in the lower left corner (betweenthe 7 and 8 o’clock positions). Be sure you’veidentified the correct camshaft TDC positionbefore dismantling, because correct valvetiming depends on you aligning them exactlyon reassembly. Note: As the engine ismounted in the engine compartment at an

angle, all references to horizontal and verticalwhilst timing the camshafts are in relation tothe crankshaft, and not the ground.4 Hold the crankshaft stationary with a socketand ratchet on the vibration damper centre bolt,then loosen (but don’t unscrew completely) thefour bolts attaching the camshaft sprocket tothe camshaft. Be very careful not to rotate thecamshaft or crankshaft. Note: Some earliermodels may have locking tabs for the camshaftsprocket bolts. Bend the tabs down beforeloosening the bolts. The tabs are no longeravailable from the manufacturer, and do nothave to be used on refitting.5 Remove the lower timing chain cover (seeSection 7).6 Unscrew and remove the four camshaftsprocket bolts, then disengage the chain fromthe crankshaft sprocket and carefully removethe chain and camshaft sprocket from theengine. It may be necessary to gently prisethe camshaft sprocket loose from thecamshaft with a screwdriver.

InspectionTiming sprockets7 Examine the teeth on both the crankshaftsprocket and the camshaft sprocket for wear.Each tooth forms an inverted V. If worn, theside of each tooth under tension will beslightly concave in shape when comparedwith the other side of the tooth (i.e. one side ofthe inverted V will be concave whencompared with the other, giving the teeth ahooked appearance). If the teeth appear to beworn, the sprockets must be renewed. Note:The crankshaft sprocket is a press fit on thecrankshaft, and can be removed with a jaw-type puller after the Woodruff key and oilpump are removed (see Section 14). However,BMW recommends the new sprocket bepressed onto the crankshaft after beingheated to 80° C (175° F) on the M10 engine, orto 200° C (390° F) on the M30 engine. For thisreason, if the crankshaft sprocket requiresrenewal, we recommend removing thecrankshaft (see Part B of this Chapter) andtaking it to an engineering works to have theold sprocket pressed off and a new onepressed on.

Timing chain8 The chain should be renewed if thesprockets are worn or if the chain is loose(indicated by excessive noise in operation).It’s a good idea to renew the chain anyway ifthe engine is stripped down for overhaul. Therollers on a very badly worn chain may beslightly grooved. To avoid future problems, ifthere’s any doubt at all about the chain’scondition, renew it.

Chain rail and tensioner9 Inspect the chain guide rail and tensionerrail for deep grooves caused by chain contact.Renew them if they are excessively worn. Therails can be renewed after removing thecirclips with a pointed tool or needle-nosepliers (see illustration).

10 Shake the tensioner plunger, and listen fora rattling sound from the check ball. If youcan’t hear the ball rattling, renew the plunger. 11 To further check the tensioner plunger,blow through it first from the closed end, thenfrom the slotted (guide) end. No air shouldflow through the plunger when you blowthrough the closed end, and air should flowthrough it freely when you blow through theslotted end. If the tensioner fails either test,renew it.

Refitting12 Refit the tensioner rail and chain guiderail, if removed.13 Temporarily refit the lower timing chaincover and vibration damper, so you can checkthe crankshaft timing marks. Once you’veverified the TDC marks are aligned, removethe damper and cover.14 Loop the timing chain over the crankshaftsprocket, then loop it over the camshaftsprocket and, guiding the chain between thechain guide and tensioner rail, refit thecamshaft sprocket on the camshaft. Makesure the camshaft timing marks are aligned.15 The remainder of refitting is the reverse ofremoval. Be sure to tighten the fasteners tothe correct torques (see this Chapter’s Speci-fications).

9 Timing belt covers - removal and refitting 2

Note: This procedure applies to M20 and M40engines.


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable.2 Remove the fan clutch and fan shroud (seeChapter 3).3 On the M20 engine, remove the radiator(see Chapter 3).4 Remove the fan drivebelt pulley.


9.6a Unbolt the distributor cap (M40 engine) . . .

8.9 To remove the tensioner or chain guiderail, remove the circlips with a pointed toolor needle-nose pliers - the circlips tend tofly off when they’re released, so make sure

you catch them or they’ll get lost (or,worse, wind up in the engine!)

5 If applicable, disconnect the referencesensor wiring harness which runs across thefront of the timing belt cover, and set it aside.6 If the distributor cap is mounted directly tothe upper timing belt cover, remove the cap,rotor and the black plastic cover beneath therotor (see illustrations).7 Remove the lower fan drivebelt pulley andvibration damper. Secure the crankshaftpulley centre bolt while you loosen the outerpulley/damper bolts (see illustration 7.7).8 Remove the bolts/nuts attaching the timingbelt covers to the engine (see illustration).9 Remove the upper cover first, then thelower cover (see illustrations). Note: Theupper cover has two alignment sleeves in thetop bolt positions. Be sure these are in placeupon reassembly.10 Refitting is the reverse of the removalprocedure. Tighten the cover bolts securely.

10 Timing belt and sprockets -removal, inspection andrefitting

5Note 1: This procedure applies to M20 andM40 engines.Note 2: Before removing the camshaftsprocket on the M40 engine, it is necessary toobtain a tool to hold the camshaft for therefitting procedure (see paragraph 10).



Removal1 Disconnect the negative cable from thebattery.2 Remove the timing belt covers (see Sec-tion 9).3 On the M40 engine, drain the coolingsystem (see Chapter 1), then disconnect the

hose, unbolt the thermostat housing andremove the thermostat (see Chapter 3).4 Set the No 1 piston at TDC (see Section 3).

Caution: Once the engine is set atTDC, do not rotate the camshaftor crankshaft until the timing beltis refitted. If the crankshaft or

camshaft is rotated with the timing beltremoved, the valves could hit the pistons,causing expensive internal engine damage.5 On the M20 engine, the crankshaft markshould be aligned with the mark on the innercover (see illustration). The mark on thecamshaft sprocket should be aligned with thestamped line on the cylinder head (seeillustration). On the M40 engine, make an


9.8 Remove all the nuts/ bolts (arrowed)that attach the upper and lower covers

(M20 engine - removed for clarity)

9.6c . . . and remove the black plasticcover

9.6b . . . then unbolt the rotor . . .

9.9c Removing the lower timing belt coveron the M40 engine

9.9b Removing the upper timing belt coveron the M40 engine

10.5b Align the mark on the camshaftsprocket with the mark on the cylinder

head (arrowed)

10.5a Align the groove in the hub on theend of the crankshaft with the notch in thefront inner cover (arrowed) and mark them

for assembly reference later on

9.9a Remove the upper timing belt coverfirst, then the lower cover (M20 engine)

1 Upper timing belt cover2 Lower timing belt cover

2A

alignment mark on the camshaft sprocket andrear timing cover to ensure correct refitting.6 On the M20 engine, loosen the twotensioner roller retaining bolts a little, andpush the tensioner towards the water pump(see illustration). With the timing belt tensionrelieved, re-tighten the retaining bolt.7 On the M40 engine, loosen the tensionerretaining nut, and use an Allen key to rotatethe tensioner clockwise. This will relieve thetension of the timing belt. Tighten theretaining nut to hold the tensioner in its freeposition.8 If the same belt is to be refitted, mark it withan arrow indicating direction of rotation.

Caution: It is not advisable torefit a timing belt which has beenremoved unless it is virtuallynew. On the M40 engine, BMW

recommend that the timing belt isrenewed every time the tensioner roller isreleased.9 Remove the timing belt by slipping it off theroller(s) and the other sprockets (seeillustrations).10 If it’s necessary to remove the camshaftor the intermediate shaft sprocket, remove thesprocket bolt while holding the sprocket toprevent it from moving. To hold the sprocket,wrap it with a piece of an old timing belt(toothed side engaging the sprocket teeth) or

a piece of leather, then hold the sprocketusing a strap spanner. If a strap spanner is notavailable, clamp the ends of the piece of beltor leather tightly together with a pair of grips.Before loosening the bolt, make sure you havethe necessary tool for positioning thecamshaft as described in the followingparagraph (see illustration).

Caution: Do not use the timingbelt you’re planning to refit tohold the sprocket. Also, be sureto hold the camshaft sprocket

very steady, because if it moves more thana few degrees, the valves could hit thepistons.Note: On the M40 engine, the sprocket is notdirectly located on the camshaft with a key, asthe groove in the end of the camshaft allowsthe sprocket to move several degrees in eitherdirection. The retaining bolt locks the sprocketonto a taper after positioning the camshaftwith a special tool. 11 The BMW tool for positioning the camshafton the M40 engine consists of a metal platewhich locates over the square lug near the No1 cylinder lobes on the camshaft - the valvecover must be removed first (seeillustrations). If the BMW tool cannot beobtained, a home-made tool should befabricated out of metal plate. The tool must bemade to hold the square lug on the camshaftat right-angles to the upper face of the cylinderhead (ie the contact face of the valve cover).12 If it’s necessary to remove the crankshaftsprocket, remove the crankshaft hub centrebolt while holding the crankshaft steady.Note: The removal of the crankshaft hubmounting bolt requires a heavy-duty holdingdevice because of the high torque used totighten the bolt. BMW has a special tool,numbered 112150 (M20 engines) or 112170(M40 engines), for this purpose. If this toolcannot be bought or borrowed, check with atool dealer or motor factors for a tool capableof doing the job. Note that the tool number112170 bolts on the rear of the cylinder headand engages with the flywheel ring gear, so itwill only be possible to use this tool if thegearbox has been removed, or if the engine isout of the vehicle (see illustrations). On


10.12a Home-made tool for holding thecrankshaft stationary while the crankshaft

pulley bolt is being loosened (engineremoved for clarity)

10.11b The BMW camshaft-holding tool inposition on the M40 engine

10.11a The BMW tool for holding thecamshaft in the TDC position on

M40 engines

10.10 Removing the camshaft sprocket onthe M40 engine

10.9b Removing the timing belt from thecamshaft sprocket on the M40 engine

10.9a When removing the timing belt onmodels with a two-piece crankshaft hub,it’s a tight fit to remove it around the hub,

but it’s a lot easier than removing thecrankshaft hub assembly, which is secured

by a very tight bolt

10.6 Loosen the idler pulley bolts(arrowed) to relieve the tension on the

timing belt so it can be removed

models with a two-piece hub, after removingthe outer hub piece, you’ll then need toremove the sprocket with a bolt-type puller(available at most motor factors). When usingthe puller, thread the crankshaft centre bolt inapproximately three turns, and use this as abearing point for the puller’s centre bolt.

Inspection13 Check for a cracked, worn or damagedbelt. Renew it if any of these conditions arefound (see illustrations). Also look at thesprockets for any signs of irregular wear ordamage, indicating the need for renewal.Note: If any parts are to be renewed, checkwith your local BMW dealer parts departmentto be sure compatible parts are used. On M20engines, later sprockets, tensioner rollers andtiming belts are marked “Z 127”. Renewal ofthe timing belt on M20 engines will mean thatthe later belt tensioner should also be fitted, ifnot already done.14 Inspect the idler roller and, on M20engines, the tension spring. Rotate thetensioner roller to be sure it rotates freely, withno noise or play. Note: When fitting a newtiming belt, it is recommended that a newtensioner be fitted also.

Refitting15 On the M20 engine, refit the idler/tensioner/spring so that the timing belt can befitted loosely.16 Refit the sprockets using a reversal of theremoval procedure; tighten the retaining boltsto the specified torque. On the M40 engine,turn the camshaft sprocket clockwise as faras possible within the location groove, thentighten the retaining bolt to an initial torque of1 to 3 Nm at this stage.17 If you are refitting the old belt, make surethe mark made to indicate belt direction ofrotation is pointing the right way (the beltshould rotate in a clockwise direction as youface the front of the engine).18 Refit the timing belt, placing the beltunder the crankshaft sprocket first to get by

the housing. Guide the belt around the othersprocket(s).19 Finally, place the belt over theidler/tensioner rollers.20 On the M20 engine, loosen the tensionerbolts and allow the spring tension to beapplied to the belt.21 On the M20 engine, lightly apply pressurebehind the tensioner to be sure springpressure is being applied to the belt (seeillustration). Don’t tighten the bolts whileapplying pressure; lightly tighten the boltsonly after releasing the tensioner.22 On the M40 engine, unbolt and removethe valve cover, then use the special tool tohold the camshaft in the TDC position (seeparagraph 11).23 On the M40 engine, loosen the tensionerroller retaining nut, and use an Allen key torotate the roller anti-clockwise until the timingbelt is tensioned correctly. The 90°-twistmethod of checking the tension of the timingbelt is not accurate enough for this engine,and it is strongly recommended that thespecial BMW tensioning tool is obtained if atall possible (apply 32 ±2 graduations on thetool) (see illustration). A reasonably accuratealternative can be made using an Allen keyand a spring balance (see illustration). Makesure that the spring balance is positioned asshown, since the tensioner roller is on aneccentric, and different readings will beobtained otherwise. The spring balanceshould be connected 85 mm along the Allenkey, and a force of 2.0 kg (4.4 lb) should be


10.13a Inspect the timing belt carefully forcracking, as shown here. . .

10.13b . . . and any other damage

10.12c Removing the crankshaft sprocketfrom the front of the crankshaft

10.12b Removing the crankshaft pulleybolt (M40 engine)

10.23b Using a spring balance and Allenkey to adjust the tension of the timing belt

on the M40 engine

Dimension A = 85 mm

10.23a Using the special BMW tool tocheck the tension of the timing belt on the

M40 engine

10.21 On the M20 engine, after the belthas been installed correctly around all

sprockets and the tensioner pulley, lightlyapply pressure to the tensioner, to be sure

the tensioner isn’t stuck and has fullmovement against the timing belt

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applied. Tighten the retaining nut to thespecified torque to hold the tensioner in itscorrect position. Note: It is important that thetiming belt is tensioned correctly. If the belt isover-tightened, it will howl, and there is thepossibility of it being damaged. If the belt istoo slack, it may jump on the sprockets.24 Check to make sure the camshaft andcrankshaft timing marks are still aligned (seeillustrations 10.5a and 10.5b).25 Turn the crankshaft clockwise throughtwo complete revolutions. (Remove thecamshaft positioning tool from the M40engine first.)

Caution: This is necessary tostretch the new belt. If not done,the belt tensioner will be tooloose, and damage could result.

26 On the M20 engine, loosen the tensionerroller bolts, then tighten them to the torquelisted in this Chapter’s Specifications.27 On the M40 engine, loosen the tensionerroller retaining nut, and re-adjust the tensionof the timing belt as described in paragraph23. On completion, tighten the tensioner rollerretaining nut, then fully tighten the camshaftsprocket bolt if previously loosened (seeillustration).28 Verify that the timing marks are stillperfectly aligned. If not, remove and refit thetiming belt.29 The remainder of refitting is the reverse ofremoval.

11 Front oil seals - renewal 5Note: Oil seals are fitted with their sealing lipsfacing inwards (towards the engine).

M10 and M30 (timing chain)engines

Camshaft front seal (M30 enginesonly)1 Remove the upper timing chain cover only(see Section 7).

2 Support the cover on two blocks of wood,and drive out the seal from behind with ahammer and screwdriver. Be very careful notto damage the seal bore in the process.3 Coat the outside diameter and lip of thenew seal with multi-purpose grease, and drivethe seal into the cover with a hammer and asocket slightly smaller in diameter than theoutside diameter of the seal.4 The remainder of refitting is the reverse ofremoval.

Crankshaft front seal (M10 and M30 engines)5 Remove the crankshaft pulley and vibrationdamper (see Section 7).6 Carefully prise the old seal out of the coverwith a large screwdriver. Be very careful not todamage the seal bore or the crankshaft withthe tool. Wrap the tip of the screwdriver with apiece of tape to prevent damage.7 Clean the bore in the cover, and coat theouter edge of the new seal with engine oil ormulti-purpose grease. Also lubricate the lipsof the seal with multi-purpose grease. Using asocket with an outside diameter slightlysmaller than the outside diameter of the seal,carefully drive the new seal into place with ahammer (see illustration). If a socket isn’tavailable, a short section of large-diameterpipe will work. Check the seal after refitting tobe sure the spring around the inside of theseal lip didn’t pop out of place.8 The remainder of refitting is the reverse ofremoval.

M20 and M40 (timing belt)engines

Camshaft front seal (M20 and M40 engines)9 Remove the timing belt and camshaftsprocket (see Section 10).10 On the M20 engine only, remove the twoscrews, and separate the camshaft sealhousing from the cylinder head by pulling it asyou rotate it back and forth.11 On the M20 engine only, support thehousing on two blocks of wood, and drive theseal out of the housing from behind using a

hammer and screwdriver. Be very careful notto damage the seal housing.12 On the M40 engine, prise the seal outfrom the cylinder head using a screwdriver,being careful not to damage the camshaftsurface or the seal bore.13 Coat the lip and outside diameter of thenew seal with multi-purpose grease.14 On the M40 engine, wrap some adhesivetape around the end of the camshaft toprotect the new seal from the location grooveas it is being fitted (see illustration).15 Carefully locate the new seal in position,and press it in by hand initially so that it entersthe bore. Drive the new seal into the housingor cylinder head (as applicable) using ahammer and a socket with a diameter slightlysmaller than the outside diameter of the seal.On the M40 engine, remove the adhesive tapefrom the end of the camshaft.16 On the M20 engine, renew the O-ring onthe back of the seal housing, and work the lipof the seal over the end of the camshaft. Refitthe screws and tighten them securely.17 The remainder of refitting is the reverse ofremoval.

Crankshaft and intermediate shaftfront seals (M20 engines)18 Remove the timing belt and crankshaftand intermediate shaft pulleys as applicable(see Section 10). Note: We recommend thetiming belt be renewed any time it is removed.19 Remove the bolts and nuts securing thefront cover to the engine block. Be sure toremove the three bolts from underneath thatconnect the front of the sump to the bottom ofthe front cover (see illustration 7.14).20 Run a sharp, thin knife between the sumpgasket and the front cover, cutting the coverfree from the gasket. Be very careful not todamage the gasket, and keep it clean so youcan re-use it. 21 Break the front cover-to-block gasket sealby tapping the cover with a rubber mallet orblock of wood and hammer. Do not prisebetween the cover and the engine block, asdamage to the gasket sealing surfaces willresult.


11.14 Fitting a new camshaft oil seal onthe M40 engine (note the adhesive tape

around the end of the camshaft to protectthe seal)

11.7 The crankshaft front oil seal ispressed into the front of the lower timing

chain cover (cover removed from theengine for clarity)

10.27 Tightening the camshaft sprocketretaining bolt on the M40 engine

22 Using a scraper, remove all traces of oldgasket material from the sealing surfaces ofthe covers and engine block.

Caution: Be very careful not toscratch or gouge the delicatealuminium surfaces. Also, do notdamage the sump gasket, and

keep it clean. Gasket removal solvents areavailable at motor factors, and may prove helpful. After all gasket material hasbeen removed, the gasket surfaces can be degreased by wiping them with a rag dampened with a suitablesolvent.

23 Support the cover on two blocks of wood,and drive out the seals from behind with ahammer and screwdriver. Be very careful notto damage the seal bores in the process.24 Coat the outside diameters and lips of thenew seals with multi-purpose grease, anddrive the seals into the cover with a hammerand a socket slightly smaller in diameter thanthe outside diameter of the seal.25 Apply a film of RTV-type gasket sealant tothe surface of the sump gasket that mateswith the front cover. Apply extra beads of RTVsealant to the edges where the gasket meetsthe engine block. Note: If the sump gasket isdamaged, instead of fitting a whole newgasket, you might try trimming the frontportion of the gasket off at the point where itmeets the engine block, then trim off the frontportion of a new sump gasket so it’s exactlythe same size. Cover the exposed inside areaof the sump with a rag, then clean all traces ofold gasket material off the area where thegasket was removed. Attach the new gasketpiece to the sump with contact-cement-typegasket adhesive, then apply RTV-type sealantas described at the beginning of thisparagraph.26 Coat both sides of the new gasket withRTV-type gasket sealant, then attach the frontcover to the front of the engine, carefullyworking the seals over the crankshaft andintermediate shaft. Refit the bolts and tightenthem evenly to the torque listed in thisChapter’s Specifications. Work from bolt-to-bolt in a criss-cross pattern, to be sure they’retightened evenly. Note 1: Tighten the frontcover-to-block bolts first, then tighten thesump-to-cover bolts. Note 2: After applyingRTV-type sealant, reassembly must becompleted in about 10 minutes so the RTVwon’t prematurely harden.27 The remainder of refitting is the reverse ofremoval.

Crankshaft front seal (M40 engines)28 Remove the timing belt and crankshaftsprocket (see Section 10).29 Remove the Woodruff key from thegroove in the end of the crankshaft.30 Note the fitted position of the oil seal, thenprise it out from the front cover using ascrewdriver, but take care not to damage thebore of the cover or the surface of the

crankshaft. If the seal is tight, drill two smallholes in the metal end of the seal, and use twoself-tapping screws to pull out the seal. Makesure all remains of swarf are removed.31 Coat the outside diameter and lip of thenew seal with multi-purpose grease, thendrive it into the cover with a hammer and asocket slightly smaller in diameter than theoutside diameter of the seal. Make sure theseal enters squarely.32 The remainder of refitting is the reverse ofremoval. Note that it is recommended that thetiming belt be renewed - see Section 10.

12 Cylinder head - removal and refitting 5

Removal1 Relieve the fuel pressure on all fuel injectionengines (see Chapter 4).2 Disconnect the negative cable from thebattery. Where the battery is located in theengine compartment, the battery may beremoved completely (see Chapter 5).

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code

before disconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

3 Remove the air cleaner assembly (seeChapter 4).4 Disconnect the wiring from the distributor(mark all wiring for position first, if necessary),and the HT lead from the coil (see Chapter 5).5 Disconnect the lead from the coolanttemperature sender unit (see Chapter 3).6 Disconnect the fuel lines from the fuel rail orcarburettor as applicable (see Chapter 4).7 Drain the cooling system (see Chapter 3).8 Clearly label then disconnect all otherhoses from the throttle body, intake manifold,carburettor and cylinder head, as applicable.9 Disconnect the throttle cable from thethrottle linkage or carburettor (see Chapter 4).10 Disconnect the exhaust manifold from thecylinder head (see Section 6). Depending onthe engine type, It may not be necessary todisconnect the manifold from the exhaustpipe; however, on right-hand-drive models,the steering column intermediate shaft maynot allow the manifold to clear the studs onthe cylinder head.11 Remove or disconnect any remaininghoses or lines from the intake manifold,including the ignition advance vacuum line(s),and the coolant and heater hoses.12 On early carburettor models, disconnectthe wiring from the alternator and startermotor.

13 Remove the intake manifold (see Sec-tion 5). Do not dismantle or remove any fuelinjection system components unless it isabsolutely necessary.14 Remove the fan drivebelt and fan (seeChapter 3).15 Remove the valve cover and gasket (seeSection 4). Remove the semi-circular rubberseal from the front of the cylinder head, wherethis is not incorporated in the valve covergasket.16 Set No 1 piston at Top Dead Centre onthe compression stroke (see Section 3).17 Remove the timing chain or belt (seeSection 8 or 10). Note: If you want to savetime by not removing and refitting the timingbelt or chain and re-timing the engine, you canunfasten the camshaft sprocket and suspendit out of the way - with the belt or chain stillattached - by a piece of rope. Be sure therope keeps firm tension on the belt or chain,so it won’t become disengaged from any ofthe sprockets.18 Loosen the cylinder head bolts a quarter-turn at a time each, in the reverse of thetightening sequence shown (see illustrations12.30a, 12.30b, 12.30c or 12.30d). Do not dismantle or remove the rocker armassembly at this time on M10, M20 and M30engines.19 Remove the cylinder head by lifting itstraight up and off the engine block. Do notprise between the cylinder head and theengine block, as damage to the gasket sealingsurfaces may result. Instead, use a blunt barpositioned in an intake port to gently prise thehead loose.20 Remove any remaining externalcomponents from the head to allow forthorough cleaning and inspection. SeeChapter 2B for cylinder head servicingprocedures. On the M40 engine, remove therubber O-ring from the groove in the top of theoil pump/front end cover housing.

Refitting21 The mating surfaces of the cylinder headand block must be perfectly clean when thehead is refitted.22 Use a gasket scraper to remove all tracesof carbon and old gasket material, then cleanthe mating surfaces with a suitable solvent. Ifthere’s oil on the mating surfaces when thehead is refitted, the gasket may not sealcorrectly, and leaks could develop. Whenworking on the block, stuff the cylinders withclean rags to keep out debris. Use a vacuumcleaner to remove material that falls into thecylinders.23 Check the block and head matingsurfaces for nicks, deep scratches and otherdamage. If the damage is slight, it can beremoved with a file; if it’s excessive,machining may be the only alternative.24 Use a tap of the correct size to chase thethreads in the head bolt holes, then clean theholes with compressed air - make sure that


2A

nothing (including oil, water, etc) remains inthe holes (see illustration).25 BMW recommend head bolts are renewed,but if the old ones are re-used, mount each boltin a vice, and run a die down the threads toremove corrosion and restore the threads. Dirt,corrosion, sealant and damaged threads willaffect torque readings (see illustration). If thebolts or their threads are damaged, do not re-use the bolts - fit a new set.26 Refit any components removed from thehead prior to cleaning and inspection. On theM40 engine, locate a new rubber O-ring in thegroove in the top of the oil pump/front endcover housing (see illustration).27 Make sure the gasket sealing surfaces of

the engine block and cylinder head are cleanand oil-free. Lay the head gasket in place onthe block, with the manufacturer’s stampedmark facing up (it usually says “UP,” “OBEN”or something similar). Use the dowel pins in thetop of the block to properly locate the gasket.28 Carefully set the cylinder head in placeon the block. Use the dowel pins to properlyalign it. Where the engine is tilted slightly (ieM40 engine) you may find it helpful to fitguide studs to ensure correct positioning ofthe cylinder head on the block. Use two oldhead bolts, one screwed into each end ofthe block. Cut the heads off the bolts, anduse a hacksaw to cut slots in the tops of the bolts so they can be removed once

the cylinder head is in position (seeillustration).29 Fit the cylinder head bolts (seeillustration).30 Tighten the cylinder head bolts, in thesequence shown, to the torque listed in thisChapter’s Specifications (see illustrations).Note that on some engines the final stage oftightening takes place after the engine hasbeen run.31 The remainder of refitting is the reverse ofremoval. Set the valve clearances on M10,M20 and M30 engines (see Chapter 1) beforerefitting the valve cover (check them againafter the engine is warmed-up). Run theengine and check for leaks.


12.30d Cylinder head bolt TIGHTENINGsequence for M40 (four-cylinder) engines

12.30c Cylinder head bolt TIGHTENINGsequence for M30 (six-cylinder) engines

12.30b Cylinder head bolt TIGHTENINGsequence for M20 (six-cylinder) engines

12.30a Cylinder head bolt TIGHTENINGsequence for M10 (four-cylinder) engines

12.29 Inserting a cylinder head bolt (M40 engine)

12.28 Lowering the cylinder head onto theblock (M40 engine)

12.26 Fitting a new rubber O-ring in thegroove in the top of the oil pump/front end

cover on the M40 engine

12.25 A die should be used to removesealant and corrosion from the head bolt

threads prior to installation

12.24 The cylinder head bolt holes shouldbe cleaned and restored with a tap (be

sure to remove debris from the holes afterthis is done)

13 Sump - removal and refitting 11 Drain the engine oil (see Chapter 1).2 Raise the front of the vehicle and place itsecurely on axle stands.3 Remove the splash shields from under theengine.4 Where applicable, disconnect the hosesattached to the sump, and move them to oneside (see illustration).5 Where applicable, disconnect the oil levelsensor electrical connector (see illustration).6 Where applicable, remove the cast-aluminium inspection cover that covers therear of the sump (see illustrations).7 On models with the M40 engine, unbolt andremove the lower sump section and removethe gasket (this is necessary for access to thefront mounting bolts). Unscrew the mountingbolt, and pull the oil dipstick tube from thesump (see illustrations). Check the conditionof the O-ring, and renew it if necessary.8 On models with the M40 engine, unscrewthe engine mounting nuts on both sides, thenattach a suitable hoist and lift the enginesufficiently to allow the sump to be removed.As a safety precaution, position axle stands orblocks of wood beneath the engine.9 Remove the bolts securing the sump to the

engine block and front/rear covers (seeillustration).10 Tap on the sump with a soft-facedhammer to break the gasket seal, and lowerthe sump from the engine.11 Using a gasket scraper, scrape off alltraces of the old gasket from the engineblock, the timing chain cover, the rear main oilseal housing, and the sump. Be especiallycareful not to nick or gouge the gasket sealingsurfaces of the timing chain cover and the oilseal housing (they are made of aluminium,and are quite soft).12 Clean the sump with solvent, and dry itthoroughly. Check the gasket sealing surfacesfor distortion. Clean any residue from the

gasket sealing surfaces on the sump andengine with a rag dampened with a suitablesolvent.13 Before refitting the sump, apply a littleRTV-type gasket sealant to the area where thefront and rear covers join the cylinder block..Lay a new sump gasket in place on the block.If necessary, apply more sealant to hold thegasket in place.14 Carefully position the sump in place (donot disturb the gasket) and refit the bolts.Start with the bolts closest to the centre of thesump, and tighten them to the torque listed inthis Chapter’s Specifications, using a criss-cross pattern. Do not overtighten them, orleakage may occur.


13.5 If applicable, disconnect the oil levelsensor connector at the left side of theengine, down near the power steering

pump mounting bracket

13.4 If applicable, remove the nut securingthe power steering lines to the sump, andmove the lines to one side to allow you to

get at the sump bolts

12.30e Angle-tightening the cylinder headbolts (M40 engine)

13.9 Remove the bolts holding the sumpto the engine block and front cover, as

shown here on a six-cylinder engine

13.7b Removing the oil dipstick tubebracket mounting bolt

13.6b . . . remove the cover to get to allthe sump bolts

13.6a Remove the four inspection coverbolts (arrowed) and . . .

13.7a Main sump retaining bolts accessedafter removal of the lower sump section onthe M40 engine (engine on bench for clarity)

2A

15 The remainder of refitting is the reverse ofremoval. Fit a new gasket to the lower sumpsection on models with the M40 engine.16 On completion refill the engine with oil(Chapter 1). Run the engine and check thatthere are no oil leaks from the sump gasket orother disturbed components.

14 Oil pump - removal,inspection and refitting 5

Removal1 Remove the sump (see Section 13).

M10, M20 and M30 engines2 On M10 and M30 engines, remove thethree bolts that attach the gear to the front ofthe pump (see illustration). Note: Somemodels have a single centre nut attaching thegear to the oil pump.3 Unbolt the oil pump from the engine block(see illustrations) and remove it.4 On the M20 engine, the intermediate shaftdrives the oil pump driveshaft, which drivesthe oil pump. To remove the driveshaft,remove the hold-down plate from the block,and lift out the plug. Check the condition ofthe O-ring, and renew it if necessary. Lift thedriveshaft out and check both gears for wear,renewing them if worn or damaged (seeillustration).5 If the gear on the intermediate shaft is worn,or the intermediate shaft bearing is worn ordamaged, the intermediate shaft must beremoved. Remove the engine (see Chap-ter 2B), then remove the timing belt,crankshaft and intermediate shaft sprockets(see Section 10) and the engine front cover(see Section 11). The intermediate shaft canbe slid out the front of the engine.

M40 engines6 Remove the timing belt as described inSection 10.7 Remove the cylinder head as described inSection 12.8 Unscrew the nut and remove the timing belttensioner from the front end cover (seeillustration). If necessary, unscrew the studfrom the cylinder block.

9 Unscrew and remove the crankshaft hubbolt while holding the crankshaft stationary.The bolt is tightened to a very high torque,and it will be necessary to prevent thecrankshaft turning. Ideally, a metal bar shouldbe bolted to the sprocket, or the starter motormay be removed and the flywheel held using awide-bladed screwdriver. Beware of possibledamage to surrounding components if it isnecessary to improvise some method ofimmobilising the crankshaft.10 Remove the sprocket and spacer, notingthat the shoulder on the spacer faces inwards.11 Unscrew the bolts and remove thestabilising and guide rollers from the front endcover (see illustrations).

12 Using a small screwdriver or similarinstrument, remove the key from the groove inthe nose of the crankshaft (see illustration).13 Pull the spacer ring off the crankshaft (seeillustration).14 Unscrew the remaining bolts, and removethe front end cover and oil pump from thecylinder block. Note the locations of the frontcover bolts, as they are of different sizes. Withthe cover removed, extract the rubber O-ringfrom the groove in the nose of the crankshaft(see illustrations).15 Note the fitted location of the oil seal, thenprise it out of the housing.


14.11b Removing the guide roller from thefront end cover (M40 engine)

14.11a Removing the stabilising rollerfrom the front end cover (M40 engine)

14.8 Removing the timing belt tensioner(M40 engine)

14.3b On M10 and M30 engines, the oilpump is bolted to the front and centre of

the engine block

14.4 If necessary on the M20 engine,remove the plug and oil pump driveshaftfrom the engine. Inspect the driveshaftgear, as well as this intermediate shaft

gear in the engine block (arrowed)

14.3a On M20 engines, the oil pump isbolted across the engine block from sideto side, towards the front of the engine

14.2 On M10 and M30 engines, remove thethree bolts that hold the driven gear to the

oil pump, and remove the gear

InspectionNote: Considering that a malfunctioning oilpump can easily cause major engine damage,we recommend that the oil pump shouldalways be renewed during engine overhaul,unless it’s in as-new condition.

M10, M20 and M30 engines16 Remove the cover and check the pumpbody, gears or rotors and cover for cracksand wear (especially in the gear or rotorcontact areas).17 Check the strainer to make sure it is notclogged or damaged.18 Lubricate the gears with clean engine oil,then attach the pump cover to the body andtighten the bolts evenly and securely.

19 Before refitting the pump - new, rebuilt ororiginal - on the engine, check it for properoperation. Fill a clean container to a depth ofone inch with fresh engine oil of therecommended viscosity.20 Immerse the oil pump inlet in the oil, andturn the driveshaft anti-clockwise by hand. Asthe shaft is turned, oil should be dischargedfrom the pump outlet.M40 engines21 With the front end cover on the bench,unscrew the bolts and remove the cover plateto expose the oil pump rotors (seeillustrations).22 Identify the rotors for position, thenremove them from the housing (seeillustrations).

23 Clean the housing and the rotorsthoroughly, then refit the rotors, making surethat they are in their previously-notedpositions. The inner rotor must be fitted withthe guide facing the body.24 Using feeler blades, measure theclearance between the oil pump body and theouter rotor, then check the clearance between the outer and inner rotors (seeillustrations).25 If the clearance is not as given in theSpecifications, the complete oil pump andfront end cover should be renewed. If theclearance is within tolerance, remove therotors, then pour a little engine oil into thehousing. Refit the rotors and turn them tospread the oil around.


14.14a Front end cover and oil pump inposition on the front of the M40 engine

14.13 Removing the spacer ring from thefront of the crankshaft

14.12 Removing the key from the groovein the nose of the crankshaft (M40 engine)

14.24a Measuring the clearance betweenthe oil pump body and the outer rotor

(M40 engine)

14.22b . . . and outer rotor from the oilpump (M40 engine)

14.22a Removing the inner rotor . . .

14.21b . . . and remove the oil pump cover(M40 engine)

14.21a Unscrew the bolts . . .14.14b Extract the rubber O-ring from thegroove in the nose of the crankshaft

(M40 engine)

2A

26 Refit the cover plate and tighten the boltsto the specified torque.27 To check the pressure relief valve, extractthe circlip and remove the sleeve, spring andpiston. Check that the length of the spring isas given in the Specifications (seeillustrations). Reassemble the pressure reliefvalve using a reversal of the dismantlingprocedure.

Refitting

M10, M20 and M30 engines28 Make sure the mounting surfaces areclean, then insert the pump into the engineblock recess. Refit the bolts and tighten themto the torque specified at the beginning of thisChapter.29 Refitting is the reverse of removal.

M40 engines30 Clean the mating surfaces, then refit thefront end cover and oil pump to the cylinderblock, together with a new gasket (seeillustration). Tighten the bolts to the specified torque. Note that there are two sizesof bolts, and they have different torquesettings.31 Fit the spacer ring on the front of thecrankshaft.32 Apply engine oil to the lips of the new oilseal, then press it into the housing to itspreviously-noted position. To ensure the oilseal enters the housing squarely, use a largesocket and the crankshaft pulley bolt to pull itinto position (see illustration).33 Refit the key to the groove in the nose ofthe crankshaft.

34 Refit the stabilising roller to the front endcover, and tighten the bolt.35 Refit the sprocket, spacer and crankshaftpulley bolt. Tighten the bolt to the specifiedtorque while holding the crankshaft stationaryusing one of the methods previouslydescribed.36 Refit the timing belt tensioning roller, butdo not tighten the bolt at this stage.37 Refit the cylinder head as described inSection 12.38 Refit the timing belt as described inSection 10.39 Refit the sump (see Section 13).

15 Flywheel/driveplate - removal and refitting 3

1 Remove the transmission (on vehicles withmanual transmission, see Chapter 7A; onvehicles with automatic transmission, seeChapter 7B).2 On vehicles with manual transmission,remove the clutch (see Chapter 8).3 Where necessary, mark the relationship ofthe flywheel/driveplate to the crankshaft, so itcan be refitted the same way. 4 The flywheel/driveplate is attached to therear of the crankshaft with eight bolts. Loosenand remove the bolts, then separate it from


14.32 Using a large socket and thecrankshaft pulley bolt to pull the oil seal

into the housing (M40 engine)14.30 Locating a new gasket on the front

of the cylinder block (M40 engine)14.27e Checking the length of the

pressure relief valve spring (M40 engine)

14.27d . . . and piston14.27c . . . spring . . .

14.27b . . . and remove the sleeve . . .14.27a Extract the circlip from the oilpump (M40 engine) . . .

14.24b Measuring the clearance betweenthe oil pump outer and inner rotors

(M40 engine)

the crankshaft flange (see illustration). Becareful - the flywheel is heavy.5 To refit the flywheel/driveplate on thecrankshaft, use a liquid thread-lockingcompound on the bolts, and tighten themgradually, using a criss-cross pattern, to thetorque listed in this Chapter’s Specifications.6 The remainder of refitting is the reverse ofremoval.

16 Crankshaft rear oil seal -renewal 3

1 Remove the flywheel or driveplate (seeSection 15).2 Remove the bolts and/or nuts attaching theseal retainer to the engine block. Be sure toremove the two bolts (from underneath)connecting the rear of the sump to the bottomof the seal retainer (see illustration).3 Run a sharp, thin knife between the sumpgasket and the seal retainer, cutting theretainer free from the gasket. Be very carefulnot to damage the gasket, and keep it cleanso you can re-use it. 4 Break the seal retainer-to-block gasket sealby tapping the retainer with a plastic mallet orblock of wood and hammer. Do not prisebetween the retainer and the engine block, asdamage to the gasket sealing surfaces willresult.5 Using a scraper, remove all traces of oldgasket material from the sealing surfaces ofthe retainer and engine block. Gasket removalsolvents are available at car accessory shops,and may prove helpful. After all gasketmaterial has been removed, the gasketsurfaces can be degreased by wiping themwith a rag dampened with a suitable solvent.

Caution: Be very careful not toscratch or gouge the delicatealuminium surfaces. Also, do notdamage the sump gasket, andkeep it clean.

6 Support the retainer on two blocks ofwood, and drive out the seal from behind witha hammer and screwdriver (see illustration).

Be very careful not to damage the seal bore inthe process.7 Coat the outside diameter and lip of thenew seal with multi-purpose grease, and drivethe seal into the retainer with a hammer and ablock of wood (see illustration).8 Apply a film of RTV-type gasket sealant tothe surface of the sump gasket that mates withthe seal retainer. Apply extra beads of RTVsealant to the edges where the gasket meetsthe engine block. Note: If the sump gasket isdamaged, instead of fitting a whole newgasket, you might try trimming the rear portionof the gasket off at the point where it meets theengine block, then trim off the rear portion of anew sump gasket so it’s exactly the same size.Cover the exposed inside area of the sumpwith a rag, then clean all traces of old gasketmaterial off the area where the gasket wasremoved. Attach the new gasket piece to thesump with contact-cement-type gasketadhesive, then apply RTV-type sealant asdescribed at the beginning of this paragraph.9 Coat both sides of the new retainer gasketwith RTV-type gasket sealant, then attach thegasket to the seal retainer. Fit the seal retainerto the rear of the engine, then refit the boltsand tighten them evenly to the torque listed inthis Chapter’s Specifications. Work from bolt-to-bolt in a criss-cross pattern to be surethey’re tightened evenly. Note 1: Tighten theretainer-to-block bolts first, then tighten thesump-to-retainer bolts. Note 2: After applyingRTV-type sealant, reassembly must be

completed in about 10 minutes so the RTVwon’t prematurely harden.10 Refit the flywheel/driveplate (see Sec-tion 15).11 Refit the transmission (on vehicles withmanual transmission, see Chapter 7A; onvehicles with automatic transmission, seeChapter 7B).

17 Engine mountings - check and renewal 1

1 Engine mountings seldom require attention,but broken or deteriorated mountings shouldbe renewed immediately, or the added strainplaced on the driveline components maycause damage or wear.

Check2 During the check, the engine must beraised slightly to remove its weight from themounts.3 Raise the vehicle and support it securely onaxle stands, then position a jack under theengine sump. Place a large block of woodbetween the jack head and the sump, thencarefully raise the engine just enough to takeits weight off the mounts.

Warning: DO NOT place any partof your body under the enginewhen it’s supported only by ajack!


16.6 After removing the retainer from theblock, support it on two wood blocks, and

drive out the old seal with a punch andhammer

16.2 Remove the six bolts from the rear ofthe block and the two from underneath at

the sump

15.4 Using a socket and ratchet, removethe eight bolts that hold the flywheel/

driveplate to the crankshaft flange - preventthe flywheel/driveplate from turning by

locking the ring gear with a lever

17.4 As engine mountings wear or age,they should be inspected for cracking or

separation from their metal plates

16.7 Drive the new seal into the retainerwith a block of wood, or a section of pipe,if you have one large enough - make surethe seal enters the retainer bore squarely

2A

4 Check the mountings to see if the rubber iscracked (see illustration), hardened orseparated from the metal plates. Sometimesthe rubber will split right down the centre.5 Check for relative movement between themounting plates and the engine or frame (usea large screwdriver or lever to attempt tomove the mountings). If movement is noted,lower the engine and tighten the mountingnuts or bolts (see illustration). Rubberpreservative should be applied to themountings, to slow deterioration.6 On models with the M40 engine, check thecondition of the dampers on each mountingby disconnecting them and attempting to

compress and expand them (see illustration).If there is very little resistance to movement,the dampers should be renewed.

Renewal7 If the dampers on the M40 engine are to berenewed, simply unscrew the bolts, then fitthe new dampers and tighten the bolts.8 To renew the mountings, disconnect thebattery negative cable, then raise the vehicleand support it securely on axle stands if youhaven’t already done so.


before disconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.9 Support the engine as described inparagraph 3.10 Remove the large bracket-to-mountingnut (see illustration). Raise the engineslightly, then remove the lower mounting-to-frame bolts/nuts and detach the mounting11 Refitting of the mountings is the reverse ofremoval. Use thread-locking compound onthe mounting bolts/nuts, and be sure totighten them securely.


17.10 To remove an engine mounting, firstremove the stud nut (arrowed) -

M30 engine shown, others similar

17.6 Engine mounting and damper on theM40 engine

17.5 Lever gently between the block andthe engine mounting attachment point

(arrowed) - if there is movement, tightenthe bolts

2B

GeneralCylinder compression pressure (all engines) . . . . . . . . . . . . . . . . . . . . . 10 to 11 barsOil pressure (all engines)

At idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 to 2.0 barsRunning (for example, at 4000 rpm) . . . . . . . . . . . . . . . . . . . . . . . . . . 4 bars or above (typically)

Cylinder head warpage limitExcept M40 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.10 mm M40 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.03 mm

Minimum cylinder head thickness (do not resurface the head to a thickness less than listed)M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128.6 mmM20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124.7 mmM40 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140.55 mm

ValvesValve stem diameter (standard)

M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 mmM20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 mmM40 engine

Intake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.975 mmExhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.960 mm

Minimum valve margin widthIntake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.191 mmExhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.98 mm

Valve stem maximum lateral movement (see text) . . . . . . . . . . . . . . . . . 0.787 mmValve face angle

Intake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45°Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45°

Chapter 2 Part B:General engine overhaul procedures

Compression check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Crankshaft - inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Crankshaft - refitting and main bearing oil clearance check . . . . . . . 24Crankshaft - removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Crankshaft rear oil seal - refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Cylinder head and components - cleaning and inspection . . . . . . . 9Cylinder head - dismantling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Cylinder head - reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Cylinder honing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Engine - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Engine block - cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Engine block - inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Engine overhaul - alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Engine overhaul - dismantling sequence . . . . . . . . . . . . . . . . . . . . . 7

Engine overhaul - general information . . . . . . . . . . . . . . . . . . . . . . . 2Engine overhaul - reassembly sequence . . . . . . . . . . . . . . . . . . . . . 21Engine removal - methods and precautions . . . . . . . . . . . . . . . . . . . 4General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Initial start-up and break-in after overhaul . . . . . . . . . . . . . . . . . . . . 27Intermediate shaft - refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Intermediate shaft - removal and inspection . . . . . . . . . . . . . . . . . . . 14Main and connecting big-end bearings - inspection . . . . . . . . . . . . 20Piston rings - refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Pistons/connecting rods - inspection . . . . . . . . . . . . . . . . . . . . . . . . 18Pistons/connecting rods - refitting and big-end bearing oil

clearance check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Pistons/connecting rods - removal . . . . . . . . . . . . . . . . . . . . . . . . . . 12Valves - servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2B•1







Specifications

Contents

Camshaft and rocker armsCamshaft bearing oil clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.033 to 0.076 mmCamshaft endfloat

M10 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.13 mmM20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 mm maximumM30 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.03 to 0.18 mmM40 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.065 to 0.150 mm

Rocker arm radial clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.015 to 0.051 mm

CrankshaftEndfloat

M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.085 to 0.174 mmM20 and M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.080 to 0.163 mm

Main bearing journal diameter (standard)M10 engines

Red classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.98 to 54.99 mmBlue classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.97 to 54.98 mm

M20 enginesRed classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59.98 to 59.99 mmBlue classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59.97 to 59.98 mm

M30 and M40 enginesYellow classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59.984 to 59.990 mmGreen classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59.977 to 59.983 mmWhite classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59.971 to 59.976 mm

Main bearing journal diameter undersizes1st undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm2nd undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50 mm3rd undersize (where applicable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 mm

Main bearing oil clearanceM10 and M20 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.030 to 0.070 mmM30 and M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.020 to 0.046 mm

Connecting rod journal diameter (standard)M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.975 to 47.991 mmM20 and M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.975 to 44.991 mm

Connecting rod journal diameter undersizes1st undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 mm2nd undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50 mm3rd undersize (where applicable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 mm

Connecting rodsConnecting rod side play (all engines) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.041 mmConnecting big-end bearing oil clearance

M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.030 to 0.070 mmM20 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.020 to 0.055 mmM40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.010 to 0.052 mm

Engine blockCylinder bore - diameter (standard)

M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.00 to 89.01 mmM20/B20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80.00 to 80.01 mmM20/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.00 to 84.01 mmM30/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.00 to 86.01 mmM30/B28 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.00 to 86.01 mmM30/B30M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.00 to 89.01 mmM30/B34 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 00 to 92.01 mmM30/B35M engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.00 to 92.01 mmM40/B16 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.000 to 84.014 mmM40/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.000 to 84.014 mm

Cylinder out-of-round limit (maximum)M20/B20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 mmM20/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.03 mmAll other engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 mm

Cylinder taper (maximum)M20/B20 and M20/B25 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 mmAll other engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 mm

2B•2 General engine overhaul procedures

Pistons and piston ringsPiston diameter (standard)

M10 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88.97 mmM20 engines

B20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79.98 mmB25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.98 mm

M30 enginesB30M

Alcan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88.970 mmKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88.980 mm

B35MAlcan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.972 mmMahle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.980 mm

M40 enginesFactory stage 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.985 mmFactory stage 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.065 mm

Piston-to-cylinder wall clearanceNew

M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.05 mmM20 and M40 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 to 0.04 mm

Service limitExcept B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.15 mmB25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.12 mm

Piston ring end gapM10 engine

Top compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.70 mmSecond compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 0.40 mmOil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 to 0.50 mm

M20 engineAll rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 0.50 mm

M30 engineTop compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 0.45 mmSecond compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.65 mmOil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.60 mm

M40 engineTop compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 1.00 mmSecond compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 1.00 mmOil ring

B16 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 1.00 mmB18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 1.40 mm

Piston ring side clearanceM10 engine

Top compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.06 to 0.09 mmSecond compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.03 to 0.072 mmOil ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.06 mm



M40 engineTop compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.20 mmSecond compression ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.10 mmOil ring

B16 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.10 mmB18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not measured

Torque wrench settings NmMain bearing cap-to-engine block bolts*

M10, M20 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60M40 engines

Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 50°

General engine overhaul procedures 2B•3

2B

Torque wrench settings (continued) NmConnecting rod cap bolts/nuts

M10 and M30 engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55M20 and M40 engines

Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle-tighten an additional 70°

Camshaft bearing caps (M40 engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Intermediate shaft sprocket-to-shaft bolt (M20 engine) . . . . . . . . . . . . . 60Oil supply tube bolt(s)

M6 (normal) and M8 (banjo) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10M5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

* BMW recommend that the main bearing bolts are renewed as a matter of course.



Included in this Part of Chapter 2 are thegeneral overhaul procedures for the cylinderhead and engine internal components.

The information ranges from adviceconcerning preparation for an overhaul andthe purchase of new parts to detailed,paragraph-by-paragraph procedures coveringremoval and refitting of internal componentsand the inspection of parts.

The following Sections have been writtenbased on the assumption that the engine hasbeen removed from the vehicle. Forinformation concerning in-vehicle enginerepair, as well as removal and refitting of theexternal components necessary for theoverhaul, see Chapter 2A, and Section 7 ofthis Part.

The Specifications included in this Part areonly those necessary for the inspection andoverhaul procedures which follow. Refer toPart A for additional Specifications.

2 Engine overhaul - general information

It’s not always easy to determine when, orif, an engine should be completelyoverhauled, as a number of factors must beconsidered.

High mileage is not necessarily anindication that an overhaul is needed, whilelow mileage doesn’t preclude the need for anoverhaul. Frequency of servicing is probablythe most important consideration. An enginethat’s had regular and frequent oil and filterchanges, as well as other requiredmaintenance, will most likely give manythousands of miles of reliable service.Conversely, a neglected engine may requirean overhaul very early in its life.

Excessive oil consumption is an indicationthat piston rings, valve seals and/or valveguides are in need of attention. Make surethat oil leaks aren’t responsible beforedeciding that the rings and/or guides areworn. Perform a cylinder compression checkto determine the extent of the work required(see Section 3).

Check the oil pressure: Unscrew the oilpressure sender unit, and connect an oilpressure gauge in its place. Measure the oilpressure with the engine at its normaloperating temperature. Compare yourreadings to the oil pressures listed in thisChapter’s Specifications. If the readings aresignificantly below these (and if the oil and oilfilter are in good condition), the crankshaftbearings and/or the oil pump are probablyworn out. On M10 and M30 engines, the oilpressure sender unit is located high on the leftrear of the cylinder head. On M20 engines, thesender unit is threaded into the side of theengine block, below the oil filter. On M40engines, the sender unit is threaded into therear of the oil filter housing.

Loss of power, rough running, knocking ormetallic engine noises, excessive valve trainnoise and high fuel consumption may alsopoint to the need for an overhaul, especially ifthey’re all present at the same time. If acomplete tune-up doesn’t remedy thesituation, major mechanical work is the onlysolution.

An engine overhaul involves restoring theinternal parts to the specifications of a newengine. During an overhaul, new piston ringsare fitted and the cylinder walls arereconditioned (rebored and/or honed). If arebore is done by an engineering works, newoversize pistons will also be fitted. The mainbearings and connecting big-end bearings aregenerally renewed and, if necessary, thecrankshaft may be reground to restore thejournals. Generally, the valves are serviced aswell, since they’re usually in less-than-perfectcondition at this point. While the engine isbeing overhauled, other components, such asthe distributor, starter and alternator, can berebuilt as well. The end result should be a like-new engine that will give many thousands oftrouble-free miles. Note: Critical coolingsystem components such as the hoses,drivebelts, thermostat and water pump MUSTbe renewed when an engine is overhauled.The radiator should be checked carefully, toensure that it isn’t clogged or leaking (seeChapters 1 or 3). Also, we don’t recommendoverhauling the oil pump - always fit a newone when an engine is rebuilt.

Before beginning the engine overhaul, readthrough the entire procedure to familiariseyourself with the scope and requirements of

the job. Overhauling an engine isn’t difficult ifyou follow all of the instructions carefully,have the necessary tools and equipment andpay close attention to all specifications;however, it is time consuming. Plan on thevehicle being tied up for a minimum of twoweeks, especially if parts must be taken to anautomotive machine shop for repair or recon-ditioning. Check on availability of parts andmake sure that any necessary special toolsand equipment are obtained in advance. Mostwork can be done with typical hand tools,although a number of precision measuringtools are required for inspecting parts todetermine if they must be replaced. Often anautomotive machine shop will handle theinspection of parts and offer adviceconcerning reconditioning and renewal. Note:Always wait until the engine has beencompletely disassembled and all components,especially the engine block, have beeninspected before deciding what service andrepair operations must be performed by anautomotive machine shop. Since the block’scondition will be the major factor to considerwhen determining whether to overhaul theoriginal engine or buy a rebuilt one, neverpurchase parts or have machine work done onother components until the block has beenthoroughly inspected. As a general rule, timeis the primary cost of an overhaul, so it doesn’tpay to refit worn or substandard parts.

As a final note, to ensure maximum life andminimum trouble from a rebuilt engine,everything must be assembled with care, in aspotlessly-clean environment.

3 Compression check 21 A compression check will tell you whatmechanical condition the upper end (pistons,rings, valves, head gaskets) of your engine isin. Specifically, it can tell you if thecompression is down due to leakage causedby worn piston rings, defective valves andseats, or a blown head gasket. Note: Theengine must be at normal operatingtemperature, and the battery must be fully-charged, for this check. 2 Begin by cleaning the area around thespark plugs before you remove them(compressed air should be used, if available,

otherwise a small brush or even a bicycle tyrepump will work). The idea is to prevent dirtfrom getting into the cylinders as thecompression check is being done.3 Remove all the spark plugs from the engine(see Chapter 1).4 Block the throttle wide open, or have anassistant hold the throttle pedal down.5 On carburettor models, disconnect the LTlead from the coil. On fuel injection models,disable the fuel pump and ignition circuit byremoving the main relay (see illustration).This is to avoid the possibility of a fire fromfuel being sprayed in the enginecompartment. The location of the main relay isgenerally near the fuse panel area under thebonnet, but refer to Chapter 12 for thespecific location on your model.6 Fit the compression gauge in the No 1spark plug hole (No 1 cylinder is nearest theradiator).7 Turn the engine on the starter motor over atleast seven compression strokes, and watchthe gauge. The compression should build upquickly in a healthy engine. Low compressionon the first stroke, followed by gradually-increasing pressure on successive strokes,indicates worn piston rings. A lowcompression reading on the first stroke, whichdoesn’t build up during successive strokes,indicates leaking valves or a blown headgasket (a cracked head could also be thecause). Deposits on the undersides of thevalve heads can also cause low compression.Record the highest gauge reading obtained.8 Repeat the procedure for the remainingcylinders, and compare the results to thecompression listed in this Chapter’s Specifi-cations.9 If compression was low, add some engineoil (about three squirts from a plunger-type oilcan) to each cylinder, through the spark plughole, and repeat the test.10 If the compression increases after the oilis added, the piston rings are definitely worn.If the compression doesn’t increase

significantly, the leakage is occurring at thevalves or head gasket. Leakage past thevalves may be caused by burned valve seatsand/or faces or warped, cracked or bentvalves.11 If two adjacent cylinders have equally lowcompression, there’s a strong possibility thatthe head gasket between them is blown. Theappearance of coolant in the combustionchambers or the crankcase would verify thiscondition.12 If one cylinder is 20 percent lower than theothers, and the engine has a slightly roughidle, a worn exhaust lobe on the camshaftcould be the cause.13 If the compression is unusually high, thecombustion chambers are probably coatedwith carbon deposits. If that’s the case, thecylinder head should be removed anddecarbonised.14 If compression is way down, or variesgreatly between cylinders, it would be a goodidea to have a leak-down test performed by agarage. This test will pinpoint exactly where the leakage is occurring and howsevere it is.

4 Engine removal - methods and precautions

If you’ve decided that an engine must beremoved for overhaul or major repair work,several preliminary steps should be taken.

Locating a suitable place to work isextremely important. Adequate work space,along with storage space for the vehicle, willbe needed. If a workshop or garage isn’tavailable, at the very least a flat, level, cleanwork surface made of concrete or asphalt isrequired.

Cleaning the engine compartment andengine before beginning the removalprocedure will help keep tools clean andorganised.

An engine hoist or A-frame will also benecessary. Make sure the equipment is ratedin excess of the combined weight of theengine and accessories. Safety is of primaryimportance, considering the potential hazardsinvolved in lifting the engine out of the vehicle.

If the engine is being removed by a novice,a helper should be available. Advice and aidfrom someone more experienced would alsobe helpful. There are many instances whenone person cannot simultaneously perform allof the operations required when lifting theengine out of the vehicle.

Plan the operation ahead of time. Arrangefor or obtain all the tools and equipment you’llneed prior to beginning the job. Some of theequipment necessary to perform engineremoval and refitting safely and with relativeease are (in addition to an engine hoist) aheavy-duty trolley jack, complete sets ofspanners and sockets as described in the

front of this manual, wooden blocks, andplenty of rags and cleaning solvent formopping up spilled oil, coolant and fuel. If thehoist must be hired, make sure that youarrange for it in advance, and perform all ofthe operations possible without it beforehand.This will save you money and time.

Plan for the vehicle to be out of use forquite a while. A machine shop will be requiredto perform some of the work which the do-it-yourselfer can’t accomplish without specialequipment. These establishments often havea busy schedule, so it would be a good ideato consult them before removing the engine,in order to accurately estimate the amount oftime required to rebuild or repair componentsthat may need work.

Always be extremely careful when removingand refitting the engine. Serious injury canresult from careless actions. Plan ahead, takeyour time and a job of this nature, althoughmajor, can be accomplished successfully.

Warning: The air conditioningsystem is under high pressure.Do not loosen any fittings orremove any components until

after the system has been discharged by aqualified engineer. Always wear eyeprotection when disconnecting airconditioning system fittings.

Caution: If removing the M40engine, it is important not to turnthe engine upside-down forlonger than 10 minutes since it is

possible for the oil to drain out of thehydraulic tappets. This would render thetappets unserviceable, and damage couldpossibly occur to the engine when it isnext started up.

5 Engine - removal and refitting 3Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you

have the correct activation code beforedisconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

Removal1 Relieve the fuel system pressure (seeChapter 4), then disconnect the negativecable from the battery. 2 Cover the wings and front panel, andremove the bonnet (see Chapter 11). Specialpads are available to protect the wings, but anold bedspread or blanket will also work.3 Remove the air cleaner housing and intakeducts (see Chapter 4).4 Drain the cooling system (see Chapter 1).5 Label the vacuum lines, emissions systemhoses, wiring connectors, earth straps andfuel lines, to ensure correct refitting, then


3.5 As a safety precaution, beforeperforming a compression check, remove

the cover and the main relay (arrowed)from the left side of the engine

compartment to disable the fuel andignition systems (525i model shown, other

models similar)

2B

detach them. Pieces of masking tape withnumbers or letters written on them work well(see illustration).

6 Label and detach all coolant hoses from theengine (see Chapter 3).7 Remove the cooling fan, shroud andradiator (see Chapter 3). Note: On the M40engine, it is only necessary to remove thecooling fan and shroud; however, preventdamage to the radiator by covering it with apiece of wood or cardboard.8 Remove the drivebelts (see Chapter 1).9 Disconnect the fuel lines from the fuel rail(see Chapter 4).

Warning: Fuel is extremelyflammable, so take extraprecautions when you work onany part of the fuel system. Don’t

smoke, or allow open flames or bare lightbulbs, near the work area, and don’t workin a garage where a natural gas-typeappliance (such as a water heater orclothes dryer) with a pilot light is present.If you spill any fuel on your skin, rinse it offimmediately with soap and water. Whenyou perform any kind of work on the fuelsystem, wear safety glasses, and have afire extinguisher on hand.10 Disconnect the accelerator cable (seeChapter 4) and kickdown linkage/speedcontrol cable (see Chapter 7B), if applicable,from the engine.11 Where fitted, unbolt the power steeringpump (see Chapter 10). Leave the lines/hosesattached, and make sure the pump is kept inan upright position in the engine compartment(use wire or rope to restrain it out of the way).12 On air-conditioned models, unbolt thecompressor (see Chapter 3) and set it aside,or tie it up out of the way. Do not disconnectthe hoses.13 Drain the engine oil (see Chapter 1) andremove the filter. Remove the engine splashguard from under the engine.14 Remove the starter motor (see Chapter 5).

15 Remove the alternator (see Chapter 5).This is not essential on all models, but it is agood idea in any case to avoid accidentaldamage.16 Unbolt the exhaust system from theengine (see Chapter 4).17 If you’re working on a vehicle with anautomatic transmission, remove the torqueconverter-to-driveplate fasteners (seeChapter 7B). On the M40 engine, unbolt theautomatic transmission fluid coolant pipesfrom the sump.18 Support the transmission with a jack.Position a block of wood between them, toprevent damage to the transmission. Specialtransmission jacks with safety chains areavailable - use one if possible.19 Attach an engine sling or a length of chainto the lifting brackets on the engine. If thebrackets have been removed, the chain canbe bolted directly to the intake manifold studs,but place a flat washer between the chain andthe nut, and tighten the nut all the way up tothe chain, to avoid the possibility of the studsbending.20 Roll the hoist into position and connectthe sling to it. Take up the slack in the sling orchain, but don’t lift the engine.

Warning: DO NOT place any partof your body under the enginewhen it’s supported only by ahoist or other lifting device.

21 On M10, M20 and M30 engines, removethe transmission rear crossmember, andslightly lower the rear of the transmission.22 Remove the transmission-to-engine blockbolts using a Torx socket. Note: The boltsholding the bellhousing to the engine blockwill require a swivel at the socket, and a verylong extension going back towards thetransmission.23 Remove the engine mounting-to-framebracket nuts. On the M40 engine, unbolt thedampers from the mountings.24 Recheck to be sure nothing is stillconnecting the engine to the transmission orvehicle. Disconnect anything still remaining.25 Raise the engine slightly. Carefully work itforwards to separate it from the transmission.If you’re working on a vehicle with anautomatic transmission, you may find thetorque converter comes forward with the

engine. If it stays with the transmission, leaveit, but you may find it easier to let it comeforward until it can be grasped easier and bepulled from the crankshaft. Note: Whenrefitting the torque converter to thetransmission before the engine is refitted, besure to renew the transmission front pumpseal, which will probably be damaged whenthe converter comes out with the engine.Either method is acceptable, but be preparedfor some fluid to leak from the torqueconverter if it comes out of the transmission. Ifyou’re working on a vehicle with a manualtransmission, draw the engine forwards untilthe input shaft is completely disengaged fromthe clutch. Slowly raise the engine out of theengine compartment. Check carefully to makesure everything is disconnected.26 Remove the flywheel/driveplate (andwhere applicable, the engine rear plate), andmount the engine on an engine stand (seeillustration). Do not turn the M40 engineupside-down (see Caution in Section 4).

Refitting27 Check the engine and transmissionmountings. If they’re worn or damaged, renewthem.28 Refit the flywheel or driveplate (seeChapter 2A). If you’re working on a manualtransmission vehicle, refit the clutch andpressure plate (see Chapter 7A). Now is agood time to fit a new clutch.29 If the torque converter came out with theengine during removal, carefully refit theconverter into the transmission before theengine is lowered into the vehicle.30 Carefully lower the engine into the enginecompartment - make sure the enginemountings line up.31 If you’re working on an automatictransmission vehicle, guide the torqueconverter onto the crankshaft following theprocedure outlined in Chapter 7B.32 If you’re working on a manualtransmission vehicle, apply a dab of high-melting-point grease to the input shaft, andguide it into the clutch and crankshaft pilotbearing until the bellhousing is flush with theengine block.. Do not allow the weight of theengine to hang on the input shaft.

33 Refit the transmission-to-engine bolts,and tighten them securely.

Caution: DO NOT use the bolts toforce the transmission andengine together.

34 Refit the remaining components in thereverse order of removal.35 Add coolant, oil, power steering andtransmission fluid as needed.


5.26 Removing the engine rear plate - M40 engine

5.5 Label each wire before unplugging theconnector

If there’s any possibility ofconfusion, make a sketch ofthe engine compartment andclearly label the lines, hosesand wires.

It may be necessary to rockthe engine slightly, or to turnthe crankshaft, to allow theinput shaft splines to matewith the clutch plate

36 Run the engine and check for leaks andproper operation of all accessories, then refitthe bonnet and test drive the vehicle.37 Where necessary, have the airconditioning system recharged and leak-tested.

6 Engine overhaul - alternatives

The do-it-yourselfer is faced with a numberof options when performing an engineoverhaul. The decision to renew the engineblock, piston/connecting rod assemblies andcrankshaft depends on a number of factors,with the number one consideration being thecondition of the block. Other considerationsare cost, access to machine shop facilities,parts availability, time required to completethe project, and the extent of prior mechanicalexperience on the part of the do-it-yourselfer.

Some of the alternatives include:Individual parts - If the inspection

procedures reveal that the engine block andmost engine components are in re-usablecondition, purchasing individual parts may bethe most economical alternative. The block,crankshaft and piston/connecting rodassemblies should all be inspected carefully.Even if the block shows little wear, thecylinder bores should be surface-honed.

Crankshaft kit - A crankshaft kit (whereavailable) consists of a reground crankshaftwith matched undersize new main andconnecting big-end bearings. Sometimes,reconditioned connecting rods and newpistons and rings are included with the kit(such a kit is sometimes called an “enginekit”). If the block is in good condition, but thecrankshaft journals are scored or worn, acrankshaft kit and other individual parts maybe the most economical alternative.

Short block - A short block consists of anengine block with a crankshaft andpiston/connecting rod assemblies alreadyfitted. New bearings are fitted, and allclearances will be correct. The existingcamshaft, valve train components, cylinderhead and external parts can be bolted to theshort block with little or no machine shopwork necessary.

Full block - A “full” or “complete” blockconsists of a short block plus an oil pump,sump, cylinder head, valve cover, camshaftand valve train components, timing sprocketsand chain (or belt) and timing cover. Allcomponents are fitted with new bearings,seals and gaskets used throughout. Therefitting of manifolds and external parts is allthat’s necessary.

Give careful thought to which alternative isbest for you, and discuss the situation withlocal machine shops, parts dealers andexperienced rebuilders before ordering orpurchasing new parts.

7 Engine overhaul - dismantling sequence

1 It’s much easier to dismantle and work onthe engine if it’s mounted on a portableengine stand. A stand can often be hired quitecheaply from a tool hire shop. Before theengine is mounted on a stand, theflywheel/driveplate should be removed fromthe engine.2 If a stand isn’t available, it’s possible todismantle the engine with it blocked up on thefloor. Be extra-careful not to tip or drop theengine when working without a stand.3 If you’re going to obtain a rebuilt engine, allthe external components listed below mustcome off first, to be transferred to the newengine if applicable. This is also the case ifyou’re doing a complete engine overhaulyourself. Note: When removing the externalcomponents from the engine, pay closeattention to details that may be helpful orimportant during refitting. Note the fittedposition of gaskets, seals, spacers, pins,brackets, washers, bolts and other small items.

Alternator and bracketsEmissions control componentsDistributor, HT leads and spark plugsThermostat and housing coverWater pumpFuel injection/carburettor and fuel systemcomponentsIntake and exhaust manifoldsOil filter and oil pressure sending unitEngine mounting brackets (see illustration)Clutch and flywheel/driveplateEngine rear plate (where applicable)

4 If you’re obtaining a short block, whichconsists of the engine block, crankshaft,pistons and connecting rods all assembled,then the cylinder head, sump and oil pumpwill have to be removed as well. See Section 6for additional information regarding thedifferent possibilities to be considered.5 If you’re planning a complete overhaul, theengine must be dismantled and the internalcomponents removed in the following generalorder:

Valve coverIntake and exhaust manifoldsTiming belt or chain coversTiming chain/beltWater pumpCylinder headSumpOil pumpPiston/connecting rod assembliesCrankshaft and main bearingsCamshaftRocker shafts and rocker arms (M10, M20and M30 engines)Cam followers and hydraulic tappets (M40 engine)Valve spring retainers and springsValves

6 Before beginning the dismantling and

overhaul procedures, make sure the followingitems are available. Also, refer to Section 21for a list of tools and materials needed forengine reassembly.

Common hand toolsSmall cardboard boxes or plastic bags forstoring partsCompartment-type metal box for storingthe hydraulic tappets (M40 engine)Gasket scraperRidge reamerVibration damper pullerMicrometersTelescoping gaugesDial indicator setValve spring compressorCylinder surfacing honePiston ring groove cleaning toolElectric drill motorTap and die setWire brushesOil gallery brushesCleaning solvent

8 Cylinder head - dismantling 41 Remove the cylinder head (see Chapter 2A).2 Remove the oil supply tube from itsmounting on top of the cylinder head (seeillustrations). Note: It’s important to renewthe seals under the tube mounting bolts.


7.3 Engine left-hand mounting bracket -M40 engine

8.2a Remove the oil tube from the top ofthe cylinder head (M10 engine). Be sure to

note the location of all gaskets andwashers for reassembly

2B

M10, M20 and M30 engines3 Adjust all valves to their maximum clearanceby rotating the eccentric on the valve end ofthe rocker arm towards the centre of the head(see Chapter 1, if necessary).4 Before removing the thrustplate, measurethe camshaft endfloat by mounting a dialindicator to the front end of the cylinder head,with the probe resting on the camshaft (seeillustration). Prise the camshaft back-and-forth in the cylinder head. The reading is thecamshaft endfloat. Compare the reading tothis Chapter’s Specifications.5 Unbolt and remove the camshaftthrustplate. Note: There are two differentlocations for the thrustplate. On M10 and M30engines, it is attached on the front of thecylinder head, behind the timing gear flange.On M20 and M40 engines, the thrustplate islocated inside the head, by the rocker shafts,at the forward end of the cylinder head.6 Remove the rear cover plate from the backof the cylinder head (see illustration).7 Remove the retaining clips from each of therocker arms. Note: There is more than onestyle of clip. The wire-type clips (seeillustration) are fitted one each side of therocker arm; the spring-steel-type goes overthe rocker arm, and clips onto either side of it.8 Before removing the rocker arm shafts,measure the rocker arm radial clearance,using a dial indicator, and compare yourmeasurement to the Specifications at the

beginning of this Chapter. Without sliding therocker arm along the shaft, try to rotate therocker arm against the shaft in each direction(see illustration). The total movementmeasured at the camshaft end of the rockerarm is the radial clearance. If the clearance isexcessive, either the rocker arm bush, rockerarm shaft, or both, will need to be renewed.9 Remove the rubber retaining plugs, or thethreaded plugs, at the front of the cylinderhead, as applicable. There is a plug in front ofeach rocker shaft.

Caution: If your engine haswelded-in retaining plugs at thefront of the rocker shafts, takethe cylinder head to a machine

shop for plug removal, to avoid possibledamage to the cylinder head or the rockerarm shafts.10 Rotate the camshaft until the most rockerarms possible are loose (not compressingtheir associated valve springs).11 For the remaining rocker arms that are stillcompressing their valve springs, BMWrecommends using a special forked tool tocompress the rocker arms against the valvesprings (and therefore take the valve springtension off the camshaft lobe). If the tool is notavailable, insert a standard screwdriver into thegap above the adjuster eccentric at the valve-end tip of each rocker arm. Using the

screwdrivers, prise the rocker arms against thevalve springs, and hold them in place as thecamshaft is removed (see the next paragraph).At least one assistant will be necessary for thisoperation, since three or four valve springsusually need compressing. If no assistance isavailable, you could try retaining thescrewdrivers that are compressing the valvesprings to the bench with lengths of sturdy wire.

Warning: Be sure the wire issecurely attached to the benchand screwdrivers, or the

screwdrivers could fly off the cylinderhead, possibly causing injury.12 When all the rocker arms are no longercontacting the camshaft lobes, slowly andcarefully pull the camshaft out the front of thecylinder head. It may be necessary to rotatethe camshaft as it is removed.

Caution: Be very careful not toscratch the camshaft bearingjournals in the cylinder head asthe camshaft is withdrawn.

13 After removing the camshaft, carefullyremove the rocker arm shafts. On modelswithout threaded holes at the front of theshafts, drive them out from the rear of thecylinder head with a hammer and hardwooddowel that is slightly smaller in diameter thanthe rocker arm shaft (see illustration). For


8.13 Removing a rocker arm shaft fromthe front of the cylinder head - the shaft

must be either driven out from the rear ofthe head with a hardwood dowel or, on

models where the rocker shaft is threadedat the front, pulled out from the front with

a slide-hammer-type puller

8.8 Check the rocker arm-to-shaft radialclearance by setting up a dial indicator asshown, and trying to rotate the rocker armagainst the shaft - DO NOT slide the rocker

arm along the shaft

8.7 Remove the retaining clips from therocker arms - the wire-type clip is shown

here

8.6 Remove the cover from the rear of thecylinder head - be sure to note the

locations of any washers, gaskets andseals while you are removing the cover

8.4 To check camshaft endfloat, mount adial indicator so that its stem is in-line with

the camshaft and just touching thecamshaft at the front

8.2b Removing the oil tube from thecamshaft bearing caps on the top of the

cylinder head (M40 engine)

rocker shafts with a threaded front hole,screw in a slide hammer to pull the shaft fromthe head.14 As each rocker arm shaft is slid out of thecylinder head, the rocker arms will bereleased, one by one.15 Drop each rocker arm into a labelled bag,so they can be returned to their originallocations on reassembly. While you’reremoving the rocker arm shafts, note theirorientation. The guide plate notches and thesmall oil holes face in; the large oil holes facedown, toward the valve guides. Also, label therocker shafts so they can be returned to theiroriginal locations in the cylinder head.

M40 enginesCaution: Keep the cylinder headupright until all of the hydraulictappets have been removed. Ifthis precaution is not taken, the

oil may drain out of the tappets and renderthem unserviceable.16 Check that the camshaft bearing caps arenumbered or identified for location.17 Progressively unscrew and remove thecamshaft bearing cap retaining bolts, thenremove the caps (see illustrations).18 Lift the camshaft from the top of thecylinder head, and remove the oil seal fromthe timing end.19 Have ready a compartmentalised boxfilled with engine oil to receive the hydraulictappets so that they are kept identified fortheir correct location (see illustration). Alsohave a further box ready to receive the camfollowers.

20 Remove the cam followers and thrustdiscs, then lift out the hydraulic tappets fromtheir bores in the cylinder head (seeillustrations).

All engines21 Before the valves are removed, arrange tolabel and store them, along with their relatedcomponents, so they can be kept separateand reinstalled in the same valve guides fromwhich they’re removed (see illustration).22 Compress the springs on the first valvewith a spring compressor, and remove thecollets (see illustration). Carefully release thevalve spring compressor, and remove theretainer, the spring and the spring seat (ifused). 23 Pull the valve out of the head, thenremove the oil seal from the guide.


8.19 Compartmentalised box to hold thehydraulic tappets (M40 engine)

8.17b . . . and camshaft - M40 engine8.17a Removing the camshaft bearingcaps . . .

8.22 Using a valve spring compressor tocompress a valve spring

8.21 A small plastic bag, with anappropriate label, can be used to store the

valve components so they can be kepttogether and refitted in the original position

8.20b . . . and thrust discs . . .8.20a Remove the cam followers . . .

8.20c . . . then lift out the hydraulic tappets

2B

If the valve binds in the guide (won’tpull through), push it back into thehead, and deburr the area around thecollet groove with a fine file orwhetstone.

24 Repeat the procedure for the remainingvalves. Remember to keep all the parts foreach valve together, so they can be refitted inthe same locations.25 Once the valves and related componentshave been removed and stored in anorganised manner, the head should bethoroughly cleaned and inspected. If acomplete engine overhaul is being done,finish the engine dismantling proceduresbefore beginning the cylinder head cleaningand inspection process.

9 Cylinder head andcomponents - cleaning and inspection

41 Thorough cleaning of the cylinder head(s)and related valve train components, followedby a detailed inspection, will enable you todecide how much valve service work must bedone during the engine overhaul. Note: If theengine was severely overheated, the cylinderhead is probably warped (see paragraph 10).

Cleaning2 Scrape all traces of old gasket material andsealing compound off the cylinder head,intake manifold and exhaust manifold sealingsurfaces. Be very careful not to gouge thecylinder head. Special gasket removalsolvents are available at motor factors.3 Remove all built-up scale from the coolantpassages.4 Run a stiff brush through the various holesto remove deposits that may have formed inthem.5 Run an appropriate-size tap into each of thethreaded holes, to remove corrosion andthread sealant that may be present. Ifcompressed air is available, use it to clear theholes of debris produced by this operation.

Warning: Wear eye protectionwhen using compressed air!

6 Clean the cylinder head with solvent, anddry it thoroughly. Compressed air will speedthe drying process, and ensure that all holes

and recessed areas are clean. Note:Decarbonising chemicals are available, andmay prove very useful when cleaning cylinderheads and valve train components. They arevery caustic, however, and should be usedwith caution. Be sure to follow the instructionson the container.7 Clean all the rocker shafts/arms/followers,springs, valve springs, spring seats, keepersand retainers with solvent, and dry themthoroughly. Clean the components from onevalve at a time, to avoid mixing up the parts.

Caution: DO NOT clean thehydraulic tappets of the M40engine; leave them completelyimmersed in oil.

8 Scrape off any heavy deposits that mayhave formed on the valves, then use amotorised wire brush to remove deposits fromthe valve heads and stems. Again, make surethe valves don’t get mixed up.

InspectionNote: Be sure to perform all of the followinginspection procedures before concluding thatmachine shop work is required. Make a list ofthe items that need attention.

Cylinder head9 Inspect the head very carefully for cracks,evidence of coolant leakage, and otherdamage. If cracks are found, check with anmachine shop concerning repair. If repair isn’tpossible, a new cylinder head should beobtained.10 Using a straightedge and feeler gauge,check the head gasket mating surface forwarpage (see illustration). If the warpageexceeds the limit listed in this Chapter’sSpecifications, it may be possible to have itresurfaced at a machine shop, providing thehead is not reduced to less than the specifiedminimum thickness.11 Examine the valve seats in each of thecombustion chambers. If they’re badly pitted,cracked or burned, the head will requireservicing that’s beyond the scope of the homemechanic.

12 Check the valve stem-to-guide clearanceby measuring the lateral movement of thevalve stem with a dial indicator (seeillustration). The valve must be in the guideand approximately 2.0 mm off the seat. Thetotal valve stem movement indicated by thegauge needle must be divided by two, toobtain the actual clearance. After this is done,if there’s still some doubt regarding thecondition of the valve guides, they should bechecked by a machine shop (the cost shouldbe minimal).

Valves13 Carefully inspect each valve face foruneven wear, deformation, cracks, pits andburned areas (see illustration). Check thevalve stem for scuffing and the neck forcracks. Rotate the valve, and check for anyobvious indication that it’s bent. Look for pitsand excessive wear on the end of the stem.The presence of any of these conditionsindicates the need for valve service asdescribed in the next Section.14 Measure the margin width on each valve(see illustration). Any valve with a marginnarrower than specified will have to bereplaced with a new one.

Valve components15 Check each valve spring for wear on theends. The tension of all springs should bechecked with a special fixture before deciding


9.14 The margin width on each valve mustbe as specified (if no margin exists, the

valve cannot be reused)

9.13 Check for valve wear at the pointsshown here

9.12 A dial indicator can be used todetermine the valve stem-to-guide

clearance (move the valve as indicated bythe arrows)

9.10 Check the cylinder head gasketsurface for warpage by trying to slip a

feeler gauge under the straightedge (seethis Chapter’s Specifications for the

maximum warpage allowed, and use afeeler gauge of that thickness)

1 Valve tip2 Collet groove3 Stem (least-worn

area)

4 Stem (most-worn area)

5 Valve face6 Margin

that they’re suitable for use in a rebuilt engine(take the springs to a machine shop for thischeck).16 Stand each spring on a flat surface, andcheck it for squareness (see illustration). Ifany of the springs are distorted or sagged, orpossibly have a broken coil, fit new parts.17 Check the spring retainers and keepersfor obvious wear and cracks. Anyquestionable parts should be renewed, asextensive damage will occur if they fail duringengine operation.

Rocker arms (M10, M20 and M30 engines)Note: The rocker arms for the exhaust valvesare the most subject to wear, and should bechecked with particular care.18 Inspect all the rocker arms for excessivewear on the tips that contact the valve stemand camshaft (see illustration). 19 Check the rocker arm radial clearance(see Section 8). If it’s excessive, either therocker arm bush or the shaft (or both) isexcessively worn. To determine which is moreworn, slide the rocker arm onto an unwornportion of the rocker arm shaft, and check theradial clearance again. If it’s now within speci-fications, the shaft is probably the most-worncomponent. If it’s not within specifications,the rocker arm bushes should be renewed.

Rocker arm shafts (M10, M20 andM30 engines)20 Check the shafts for scoring, excessivewear and other damage. The areas where the

rocker arms contact the shafts should besmooth. If there is a visible ridge at the edgeof where the rocker arm rides, the shaft isprobably worn excessively.

Cam followers and hydraulic tappets(M40 engines)21 Check the cam followers where theycontact the valve stems and pivot posts forwear, scoring and pitting. If there is excessivewear on both the followers and camshaft,then a new camshaft, complete with camfollowers, must be obtained.22 Similarly check the hydraulic tappets wherethey contact the bores in the cylinder head forwear, scoring and pitting. Occasionally, ahydraulic tappet may be noisy and requirerenewal, and this will have been noticed whenthe engine was running. It is not easy to check atappet for internal damage or wear once it hasbeen removed; if there is any doubt, a completeset of new tappets should be fitted.Camshaft23 Inspect the camshaft journals (the roundbearing areas) and lobes for scoring, pitting,flaking and excessive wear. Using amicrometer, measure the height of eachexhaust and intake lobe. Compare the heightsof all the exhaust lobes and intake lobes. If thereadings among the exhaust valve lobes orintake valve lobes vary more than about 0.08 mm, or if the camshaft is exhibiting anysigns of wear, renew the camshaft.24 Inspect the camshaft bearing surfaces inthe cylinder head for scoring and otherdamage. If the bearing surfaces are scored ordamaged, you’ll normally have to renew thecylinder head, since the bearings are simply amachined surface in the cylinder head. Note:A machine shop (particularly one thatspecialises in BMWs) or dealer servicedepartment may be able to provide analternative to fitting a new cylinder head, if theonly problem with the head is mildly-scoredcamshaft bearing surfaces.25 Using a micrometer, measure the journalson the camshaft, and record themeasurements (see illustration). Using atelescoping gauge or inside micrometer,

measure the camshaft bearing diameters in thecylinder head (on the M40 engine, refit thebearing caps first). Subtract the camshaftjournal measurement from its correspondingbearing inside diameter to obtain the oilclearance. Compare the oil clearance to what’slisted in this Chapter’s Specifications. If it’s notwithin tolerance, a new camshaft and/orcylinder head will be required. Note: Beforefitting a new cylinder head, check with amachine shop (particularly one that specialisesin BMWs). They may be able to repair the head.

10 Valves - servicing 41 Examine the valves as described in Sec-tion 9, paragraphs 13 and 14. Renew anyvalve that shows signs of wear or damage.2 If the valve appears satisfactory at thisstage, measure the valve stem diameter atseveral points using a micrometer (seeillustration 9.13). Any significant difference inthe readings obtained indicates wear of thevalve stem. Should any of these conditions beapparent, the valve(s) must be renewed.3 If the valves are in satisfactory condition theyshould be ground (lapped) into their respectiveseats to ensure a gas-tight seal. If the seat isonly lightly pitted, or if it has been re-cut, finegrinding compound should be used to producethe required finish. Coarse valve-grindingcompound should not normally be used,unless a seat is badly burned or deeply pitted.If this is the case, the cylinder head and valvesshould be inspected by an expert, to decidewhether seat re-cutting or even the renewal ofthe valve or seat insert is required.4 Valve grinding is carried out as follows.Place the cylinder head upside-down on abench, with a block of wood at each end togive clearance for the valve stems.5 Smear a trace of the appropriate grade ofvalve-grinding compound on the seat face,and press a suction grinding tool onto thevalve head. With a semi-rotary action, grindthe valve head to its seat, lifting the valveoccasionally to redistribute the grindingcompound (see illustration).


9.25 Measure each camshaft bearingjournal and its corresponding bearing

diameter in the cylinder head, then subtractthe journal diameter from the bearing

inside diameter to obtain the oil clearance

9.18 Look for signs of pitting, discolorationor excessive wear on the ends of therocker arms where they contact the

camshaft and the valve stem tip

10.5 Grinding-in a valve - do not grind-inthe valves any more than absolutely

necessary, or their seats will beprematurely sunk into the cylinder head

2B

9.16 Check each valve spring forsquareness

6 If coarse grinding compound is being used,work only until a dull, matt even surface isproduced on both the valve seat and thevalve, then wipe off the used compound andrepeat the process with fine compound. Whena smooth, unbroken ring of light grey mattfinish is produced on both the valve and seat,the grinding operation is complete. Do notgrind in the valves any further than absolutelynecessary.7 When all the valves have been ground-in,carefully wash off all traces of grindingcompound using paraffin or a suitable solventbefore reassembly of the cylinder head.

11 Cylinder head - reassembly 51 Make sure the cylinder head is spotlessly-clean before beginning reassembly.2 If the head was sent out for valve servicing,the valves and related components willalready be in place. Begin the reassemblyprocedure with paragraph 8.3 Starting at one end of the head, apply

molybdenum disulphide (“moly”) grease orclean engine oil to each valve stem, and refitthe first valve.4 Lubricate the lip of the valve guide seal,carefully slide it over the tip of the valve, thenslide it all the way down the stem to the guide.Using a hammer and a deep socket or seal-fitting tool, gently tap the seal into place untilit’s completely seated on the guide (seeillustrations). Don’t twist or distort a sealduring fitting, or it won’t seal properly againstthe valve stem. Note: On some engines, theseals for intake and exhaust valves aredifferent - don’t mix them up.5 Drop the spring seat or shim(s) over thevalve guide, and set the valve spring andretainer in place.6 Compress the spring with a valve springcompressor and carefully refit the collets inthe upper groove, then slowly release thecompressor and make sure the collets seatproperly (see illustration).

7 Repeat paragraphs 3 to 6 for each of thevalves. Be sure to return the components totheir original locations - don’t mix them up!

M10, M20 and M30 engines8 Refit the rocker arms and shafts byreversing the dismantling sequence. Be sureto refit the rocker shafts in the correctorientation. The guide plate notches and thesmall oil holes face inwards; the large oil holesface down, toward the valve guides. 9 Lubricate the camshaft journals and lobes

(see illustration), then carefully insert it intothe cylinder head, rotating it as you go so thecamshaft lobes will clear the rocker arms. Itwill also be necessary to compress the rockerarms against the valve springs, as describedin Section 8, so they’ll clear the camshaftlobes. Be very careful not to scratch or gougethe camshaft bearing surfaces in the cylinderhead.

M40 engines10 Lubricate the bores for the hydraulictappets in the cylinder head, then insert thetappets in their original positions.11 Locate the thrust discs and cam followerson the valves and pivot posts in their originalpositions.12 Lubricate the bearing surfaces of thecamshaft in the cylinder head.13 Locate the camshaft in the cylinder headso that the valves of No 1 cylinder are bothopen, and the valves of No 4 cylinder are“rocking” (exhaust closing and inlet opening).No 1 cylinder is at the timing belt end. 14 Lubricate the bearing surfaces in thebearing caps, then locate them in their correctpositions and insert the retaining bolts.Progressively tighten the bolts to the specifiedtorque.15 Fit a new oil seal to the camshaft frontbearing cap (see Chapter 2A, Section 11).

All engines16 Refit the oil supply tube to the top of thecylinder head together with new seals, thentighten the bolts to the specified torque.17 The cylinder head may now be refitted(see Chapter 2A).

12 Pistons/connecting rods -removal 5

Note: Before removing the piston/connectingrod assemblies, remove the cylinder head andthe sump. On M10, M20 and M30 enginesonly, remove the oil pump. Refer to theappropriate Sections in Chapter 2A.1 Use your fingernail to feel if a ridge hasformed at the upper limit of ring travel (about 6 mm down from the top of each cylinder). If


11.9 Lubricate the camshaft bearingjournals and lobes with engine assemblypaste or molybdenum disulphide (“moly”)

grease

11.6 With the retainer fitted, compress thevalve spring and refit the collets as shown

11.4b . . .then lightly drive on the seal witha socket or piece of tubing

11.4a Lubricate the valve guide seal, andplace it on the guide (the valve should be

in place too) . . .

A light spring placed underthe valve head will greatlyease the valve grindingoperation.

Apply a small dab of grease to eachcollet to hold it in place, if necessary.

carbon deposits or cylinder wear haveproduced ridges, they must be completelyremoved with a special tool called a ridgereamer (see illustration). Follow themanufacturer’s instructions provided with thetool. Failure to remove the ridges beforeattempting to remove the piston/connectingrod assemblies may result in piston ringbreakage.2 After the cylinder ridges have beenremoved, turn the engine upside-down so thecrankshaft is facing up.3 Before the connecting rods are removed,check the side play with feeler gauges. Slidethem between the first connecting rod andcrankshaft web until no play is apparent (seeillustration). The side play is equal to thethickness of the feeler gauge(s). If the sideplay exceeds the service limit, newconnecting rods will be required. If new rods(or a new crankshaft) are fitted, ensure thatsome side play is retained (if not, the rods willhave to be machined to restore it - consult amachine shop for advice if necessary). Repeatthe procedure for the remaining connectingrods.4 Check the connecting rods and caps foridentification marks. If they aren’t plainlymarked, use a small centre-punch to makethe appropriate number of indentations (seeillustration) on each rod and cap (1, 2, 3, etc.,depending on the cylinder they’re associatedwith).5 Loosen each of the connecting rod capnuts/bolts a half-turn at a time until they canbe removed by hand. Remove the No 1connecting rod cap and bearing shell. Don’tdrop the bearing shell out of the cap.6 Where applicable, slip a short length ofplastic or rubber hose over each connectingrod cap stud to protect the crankshaft journaland cylinder wall as the piston is removed(see illustration).7 Remove the bearing shell, and push theconnecting rod/piston assembly out throughthe top of the engine. Use a wooden hammerhandle to push on the upper bearing surfacein the connecting rod. If resistance is felt,double-check to make sure that all of theridge was removed from the cylinder.

8 Repeat the procedure for the remainingcylinders.9 After removal, reassemble the connectingrod caps and bearing shells in their respectiveconnecting rods, and refit the cap nuts/boltsfinger-tight. Leaving the old bearing shells inplace until reassembly will help prevent theconnecting big-end bearing surfaces frombeing accidentally nicked or gouged.10 Don’t separate the pistons from theconnecting rods (see Section 18).

13 Crankshaft - removal 5Note: The crankshaft can be removed onlyafter the engine has been removed from thevehicle. It’s assumed that the flywheel ordriveplate, vibration damper, timing chain orbelt, sump, oil pump and piston/connectingrod assemblies have already been removed.The rear main oil seal housing must beunbolted and separated from the block beforeproceeding with crankshaft removal.1 Before the crankshaft is removed, checkthe endfloat. Mount a dial indicator with thestem in line with the crankshaft and touchingthe nose of the crankshaft, or one of its webs(see illustration).2 Push the crankshaft all the way to the rear,

and zero the dial indicator. Next, prise thecrankshaft to the front as far as possible, andcheck the reading on the dial indicator. Thedistance that it moves is the endfloat. If it’sgreater than the maximum endfloat listed inthis Chapter’s Specifications, check thecrankshaft thrust surfaces for wear. If no wearis evident, new main bearings should correctthe endfloat.3 If a dial indicator isn’t available, feelergauges can be used. Identify the main bearingwith the thrust flanges either side of it - this isreferred to as the “thrust” main bearing (seeSection 24, paragraph 6). Gently prise or pushthe crankshaft all the way to the front of theengine. Slip feeler gauges between thecrankshaft and the front face of the thrustmain bearing to determine the clearance.4 Check the main bearing caps to see ifthey’re marked to indicate their locations.They should be numbered consecutively fromthe front of the engine to the rear. If theyaren’t, mark them with number-stamping diesor a centre-punch (see illustration). Mainbearing caps generally have a cast-in arrow,which points to the front of the engine.Loosen the main bearing cap bolts a quarter-turn at a time each, working from the outerends towards the centre, until they can beremoved by hand. Note if any stud bolts areused, and make sure they’re returned to theiroriginal locations when the crankshaft isrefitted.


12.4 Mark the big-end bearing caps inorder from the front of the engine to therear (one mark for the front cap, two for

the second one and so on)

12.3 Check the connecting rod side playwith a feeler gauge as shown

12.1 A ridge reamer is required to removethe ridge from the top of each cylinder - do

this before removing the pistons!

13.1 Checking crankshaft endfloat with adial indicator

12.6 To prevent damage to the crankshaftjournals and cylinder walls, slip sections of

rubber or plastic hose over the rod boltsbefore removing the pistons

2B

5 Gently tap the caps with a soft-facedhammer, then separate them from the engineblock. If necessary, use the bolts as levers toremove the caps. Try not to drop the bearingshells if they come out with the caps.6 Carefully lift the crankshaft out of theengine. It may be a good idea to have anassistant available, since the crankshaft isquite heavy (see illustration). With thebearing shells in place in the engine block andmain bearing caps, return the caps to theirrespective locations on the engine block, andtighten the bolts finger-tight.

14 Intermediate shaft - removal and inspection 5

Note: The intermediate shaft is used on theM20 engine only. The shaft rotates in theengine block parallel to the crankshaft. It isdriven by the timing belt, and its only purposeis to drive the oil pump.1 Remove the timing belt (see Chapter 2A).2 With the belt removed, unbolt the gear fromthe intermediate shaft and unbolt the frontcover.3 Remove the oil pump driveshaft (seeChapter 2A).4 The shaft is held in the cylinder block by aretaining plate with two bolts. Remove thebolts, and pull the shaft forwards and out ofthe block.5 Look for any signs of abnormal wear on thebearing surfaces or the gear at the back endof the shaft, which drives the oil pump shaft. Ifthe bearing surfaces in the engine block showwear, they’ll have to be attended to by amachine shop.

15 Engine block - cleaning 2Caution: The core plugs may bedifficult or impossible to retrieveif they’re driven into the blockcoolant passages.

1 Remove the core plugs from the engineblock. To do this, knock one side of each pluginto the block with a hammer and punch,grasp the other side by its edge with largepliers, and pull it out.2 Using a gasket scraper, remove all traces ofgasket material from the engine block. Be verycareful not to nick or gouge the gasket sealingsurfaces.3 Remove the main bearing caps, andseparate the bearing shells from the caps andthe engine block. Tag the bearings, indicatingwhich cylinder they were removed from andwhether they were in the cap or the block,then set them aside.4 Remove all of the threaded oil gallery plugsfrom the block. The plugs are usually verytight - they may have to be drilled out and the

holes retapped. Use new plugs when theengine is reassembled.5 If the engine is extremely dirty, it should betaken to a machine shop to be steam-cleaned.6 After the block is returned, clean all oilholes and oil galleries one more time. Brushesspecifically designed for this purpose areavailable at most motor factors. Flush thepassages with warm water until the water runsclear, dry the block thoroughly, and wipe allmachined surfaces with a light, rust-preventive oil. If you have access tocompressed air, use it to speed the dryingprocess and to blow out all the oil holes andgalleries.

Warning: Wear eye protectionwhen using compressed air!

7 If the block isn’t extremely dirty or sludgedup, you can do an adequate cleaning job withhot soapy water and a stiff brush. Take plentyof time, and do a thorough job. Regardless ofthe cleaning method used, be sure to clean alloil holes and galleries very thoroughly, dry theblock completely, and coat all machinedsurfaces with light oil.8 The threaded holes in the block must beclean to ensure accurate torque readings

during reassembly. Run the proper-size tapinto each of the holes to remove rust,corrosion, thread sealant or sludge, and torestore damaged threads (see illustration). Ifpossible, use compressed air to clear theholes of debris produced by this operation. Besure also that the holes are dry - any oil orother fluid present could cause the block tobe cracked by hydraulic pressure when thebolts are tightened. Now is a good time toclean the threads on all bolts. Note that BMWrecommend that the cylinder head bolts andmain bearing bolts are renewed as a matter ofcourse.9 Refit the main bearing caps, and tighten thebolts finger-tight.10 After coating the sealing surfaces of thenew core plugs with a suitable sealant, refitthem in the engine block (see illustration).Make sure they’re driven in straight andseated properly, or leakage could result.Special tools are available for this purpose,but a large socket, with an outside diameterthat will just slip into the core plug, a 1/2-inchdrive extension, and a hammer, will work justas well.11 Apply non-hardening sealant to the newoil gallery plugs, and thread them into theholes in the block. Make sure they’retightened securely.12 If the engine isn’t going to bereassembled right away, cover it with a largeplastic bag to keep it clean.


15.10 A large socket on an extension canbe used to drive the new core plugs into

the block

15.8 All bolt holes in the block -particularly the main bearing cap and head

bolt holes - should be cleaned andrestored with a tap (be sure to removedebris from the holes after this is done)

13.6 Remove the crankshaft by liftingstraight up. Be very careful when removing

the crankshaft - it is very heavy

13.4 Use a centre-punch or number-stamping dies to mark the main bearingcaps to ensure refitting in their originallocations on the block (make the punch

marks near one of the bolt heads)

16 Engine block - inspection 31 Before the block is inspected, it should becleaned (see Section 15).2 Visually check the block for cracks, rustand corrosion. Look for stripped threads inthe threaded holes. It’s also a good idea tohave the block checked for hidden cracks bya machine shop that has the specialequipment to do this type of work. If defectsare found, have the block repaired, if possible;otherwise, a new block will be required.3 Check the cylinder bores for scuffing andscoring.4 Measure the diameter of each cylinder atthe top (just under the wear ridge area), centreand bottom of the cylinder bore, parallel to thecrankshaft axis (see illustrations). 5 Next, measure each cylinder’s diameter atthe same three locations across thecrankshaft axis. Compare the results to thisChapter’s Specifications.6 If the required precision measuring toolsaren’t available, the piston-to-cylinderclearances can be obtained, though not quiteas accurately, using feeler gauges.7 To check the clearance, select a feelergauge, and slip it into the cylinder along withthe matching piston. The piston must bepositioned exactly as it normally would be.The feeler gauge must be between the pistonand cylinder on one of the thrust faces (90° tothe gudgeon pin bore).8 The piston should slip through the cylinder(with the feeler gauge in place) with moderatepressure.9 If it falls through or slides through easily, theclearance is excessive, and a new piston willbe required. If the piston binds at the lowerend of the cylinder and is loose toward thetop, the cylinder is tapered. If tight spots areencountered as the piston/feeler gauge isrotated in the cylinder, the cylinder is out-of-round.10 Repeat the procedure for the remainingpistons and cylinders.11 If the cylinder walls are badly scuffed or

scored, or if they’re out-of-round or taperedbeyond the limits given in this Chapter’sSpecifications, have the engine block reboredand honed at a machine shop. If a rebore isdone, oversize pistons and rings will berequired.12 If the cylinders are in reasonably goodcondition and not worn to the outside of thelimits, and if the piston-to-cylinder clearancescan be maintained properly, then they don’thave to be rebored. Honing (see Section 17)and a new set of piston rings is all that’snecessary.

17 Cylinder honing 31 Prior to engine reassembly, the cylinderbores must be honed so the new piston ringswill seat correctly and provide the bestpossible combustion chamber seal. Note: Ifyou don’t have the tools, or don’t want totackle the honing operation, most machineshops will do it for a reasonable fee.2 Before honing the cylinders, refit the mainbearing caps, and tighten the bolts to thetorque listed in this Chapter’s Specifications.3 Two types of cylinder hones are commonlyavailable - the flex hone or “bottle brush”

type, and the more traditional surfacing honewith spring-loaded stones. Both will do thejob, but for the less-experienced mechanic,the “bottle brush” hone will probably be easierto use. You’ll also need some paraffin orhoning oil, rags and an electric drill. Proceedas follows.4 Mount the hone in the drill, compress thestones, and slip it into the first cylinder (seeillustration). Be sure to wear safety gogglesor a face shield!5 Lubricate the cylinder with plenty of honingoil, turn on the drill, and move the hone up anddown in the cylinder at a pace that willproduce a fine crosshatch pattern on thecylinder walls. Ideally, the crosshatch linesshould intersect at approximately a 60° angle(see illustration). Be sure to use plenty oflubricant, and don’t take off any more materialthan is absolutely necessary to produce thedesired finish. Note: Piston ring manufacturersmay specify a smaller crosshatch angle thanthe traditional 60° - read and follow anyinstructions included with the new rings.6 Don’t withdraw the hone from the cylinderwhile it’s running. Instead, shut off the drilland continue moving the hone up and down inthe cylinder until it comes to a complete stop,then compress the stones and withdraw thehone. If you’re using a “bottle brush” typehone, stop the drill, then turn the chuck in thenormal direction of rotation while withdrawingthe hone from the cylinder.


16.4c The gauge is then measured with amicrometer to determine the bore size

16.4b The ability to “feel” when thetelescoping gauge is at the correct point

will be developed over time, so workslowly, and repeat the check until you’re

satisfied the bore measurement is accurate

16.4a Measure the diameter of eachcylinder just under the wear ridge (A), at

the centre (B) and at the bottom (C)

17.5 The cylinder hone should leave asmooth, crosshatch pattern, with the linesintersecting at approximately a 60° angle

17.4 A “bottle brush” hone will producebetter results if you’ve never honed

cylinders before

2B

7 Wipe the oil out of the cylinder, and repeatthe procedure for the remaining cylinders.8 After the honing job is complete, chamferthe top edges of the cylinder bores with asmall file, so the rings won’t catch when thepistons are refitted. Be very careful not to nickthe cylinder walls with the end of the file.9 The entire engine block must be washedagain very thoroughly with warm, soapywater, to remove all traces of the abrasive gritproduced during the honing operation. Note:The bores can be considered clean when alint-free white cloth - dampened with cleanengine oil - used to wipe them out doesn’tpick up any more honing residue, which willshow up as grey areas on the cloth. Be sure torun a brush through all oil holes and galleries,and flush them with running water.10 After rinsing, dry the block, and apply acoat of light rust-preventive oil to all machinedsurfaces. Wrap the block in a plastic bag tokeep it clean, and set it aside untilreassembly.

18 Pistons/connecting rods -inspection 3

1 Before the inspection process can becarried out, the piston/connecting rodassemblies must be cleaned and the originalpiston rings removed from the pistons. Note:Always use new piston rings when the engineis reassembled.2 Using a piston ring refitting tool, carefullyremove the rings from the pistons. Be carefulnot to nick or gouge the pistons in theprocess (see illustration).3 Scrape all traces of carbon from the top ofthe piston. A hand-held wire brush or a pieceof fine emery cloth can be used once themajority of the deposits have been scrapedaway. Do not, under any circumstances, use awire brush mounted in a drill motor to removedeposits from the pistons. The piston materialis soft, and may be damaged by the wirebrush.4 Use a piston ring groove cleaning tool toremove carbon deposits from the ringgrooves. Be very careful to remove only the

carbon deposits - don’t remove any metal,and do not nick or scratch the sides of thering grooves (see illustration).

5 Once the deposits have been removed,clean the piston/rod assemblies with solvent,and dry them with compressed air (ifavailable). Make sure the oil return holes in theback sides of the ring grooves are clear.6 If the pistons and cylinder walls aren’tdamaged or worn excessively, and if theengine block is not rebored, new pistonswon’t be necessary. Normal piston wearappears as even vertical wear on the pistonthrust surfaces (90° to the gudgeon pin bore),and slight looseness of the top ring in itsgroove. New piston rings, however, shouldalways be used when an engine is rebuilt.7 Carefully inspect each piston for cracksaround the skirt, at the pin bosses, and at thering lands.8 Look for scoring and scuffing on the thrustfaces of the skirt, holes in the piston crown,and burned areas at the edge of the crown. Ifthe skirt is scored or scuffed, the engine mayhave been suffering from overheating and/orabnormal combustion, which causedexcessively high operating temperatures. Thecooling and lubrication systems should bechecked thoroughly. A hole in the piston crownis an indication that abnormal combustion (pre-ignition) was occurring. Burned areas at theedge of the piston crown are usually evidenceof spark knock (detonation). If any of the above

problems exist, the causes must be corrected,or the damage will occur again. The causesmay include intake air leaks, incorrect fuel/airmixture, or incorrect ignition timing. On latervehicles with high levels of exhaust emissioncontrol, including catalytic converters, theproblem may be with the EGR (exhaust gasrecirculation) system, where applicable.9 Corrosion of the piston, in the form of smallpits, indicates that coolant is leaking into thecombustion chamber and/or the crankcase.Again, the cause must be corrected or theproblem may persist in the rebuilt engine.10 Measure the piston ring side clearance bylaying a new piston ring in each ring grooveand slipping a feeler gauge in beside it (seeillustration). Check the clearance at three orfour locations around each groove. Be sure touse the correct ring for each groove - they aredifferent. If the side clearance is greater thanthe figure listed in this Chapter’s Specifi-cations, new pistons will have to be used.11 Check the piston-to-bore clearance bymeasuring the bore (see Section 16) and thepiston diameter. Make sure the pistons andbores are correctly matched. Measure thepiston across the skirt, at 90° to, and in linewith, the gudgeon pin (see illustration). (Anydifference between these two measurementsindicates that the piston is no longer perfectlyround.) Subtract the piston diameter from thebore diameter to obtain the clearance. If it’sgreater than specified, the block will have tobe rebored, and new pistons and rings fitted.


18.11 Measure the piston diameter at a90-degree angle to the gudgeon pin, at the

same height as the gudgeon pin

18.10 Check the ring side clearance with afeeler gauge at several points around the

groove

18.4 The piston ring grooves can becleaned with a special tool, as shown

here

18.2 Removing the compression rings witha ring expander - note the mark (arrowed)

facing up

If a groove cleaning tool isn’t available,a piece broken off the old ring will dothe job, but protect your hands - pistonrings can be sharp

12 Check the piston-to-rod clearance bytwisting the piston and rod in oppositedirections. Any noticeable play indicatesexcessive wear, which must be corrected. Thepiston/connecting rod assemblies should betaken to a machine shop for attention.13 If the pistons must be removed from theconnecting rods for any reason, they shouldbe taken to a machine shop. When this isdone, have the connecting rods checked forbend and twist, since most machine shopshave special equipment for this purpose.Note: Unless new pistons and/or connectingrods must be fitted, do not dismantle thepistons and connecting rods.14 Check the connecting rods for cracks andother damage. Temporarily remove the rodcaps, lift out the old bearing shells, wipe the rodand cap bearing surfaces clean, and inspectthem for nicks, gouges and scratches. Afterchecking the rods, fit new bearing shells, slip thecaps into place, and tighten the nuts finger-tight.

19 Crankshaft - inspection 31 Remove all burrs from the crankshaft oilholes with a stone, file or scraper (seeillustration).

2 Clean the crankshaft with solvent, and dry itwith compressed air (if available). Be sure toclean the oil holes with a stiff brush (seeillustration), and flush them with solvent.3 Check the main and connecting big-endbearing journals for uneven wear, scoring, pitsand cracks.4 Rub a copper coin across each journalseveral times (see illustration). If a journalpicks up copper from the coin, it’s too roughand must be reground.5 Check the rest of the crankshaft for cracksand other damage. If necessary, have amachine shop inspect the crankshaft.6 Using a micrometer, measure the diameterof the main and connecting rod journals, andcompare the results to this Chapter’s Specifi-cations (see illustration). By measuring thediameter at a number of points around eachjournal’s circumference, you’ll be able todetermine whether or not the journal is out-of-round. Take the measurement at each end ofthe journal, near the crank webs, to determineif the journal is tapered.7 If the crankshaft journals are damaged,tapered, out-of-round or worn beyond thelimits given in the Specifications, have thecrankshaft reground by a machine shop. Besure to use the correct-size bearing shells ifthe crankshaft is reconditioned.8 Check the oil seal journals at each end of

the crankshaft for wear and damage. If theseal has worn a groove in the journal, or if it’snicked or scratched (see illustration), thenew seal may leak when the engine isreassembled. In some cases, a machine shopmay be able to repair the journal by pressingon a thin sleeve. If repair isn’t feasible, a newor different crankshaft should be fitted.9 Examine the main and big-end bearingshells (see Section 20).

20 Main and connecting big-end bearings - inspection 3

1 Even though the main and connecting big-end bearings should be renewed during theengine overhaul, the old bearings should beretained for close examination, as they mayreveal valuable information about thecondition of the engine (see illustration).2 Bearing failure occurs because of lack oflubrication, the presence of dirt or otherforeign particles, overloading the engine, andcorrosion. Regardless of the cause of bearingfailure, it must be corrected before the engineis reassembled, to prevent it from happeningagain.


19.4 Rubbing a penny lengthways on eachjournal will reveal its condition - if copper

rubs off and is embedded in the crankshaft,the journals should be reground

19.2 Use a wire or stiff plastic bristlebrush to clean the oil passages in the

crankshaft

19.1 The oil holes should be chamfered sosharp edges don’t gouge or scratch the

new bearings

20.1 Typical bearing failures

A Scratched by dirt: debris embedded intobearing material

B Lack of oil: overlay wiped outC Improper seating: bright (polished) sectionsD Tapered journal: overlay gone from entire

surfaceE Radius rideF Fatigue failure: craters or pockets

19.8 If the seals have worn grooves in thecrankshaft journals, or if the seal contactsurfaces are nicked or scratched, the new

seals will leak

19.6 Measure the diameter of eachcrankshaft journal at several points to

detect taper and out-of-round conditions

2B

3 When examining the bearings, removethem from the engine block, the main bearingcaps, the connecting rods and the rod caps,and lay them out on a clean surface in thesame general position as their location in theengine. This will enable you to match anybearing problems with the correspondingcrankshaft journal.4 Dirt and other foreign particles get into theengine in a variety of ways. It may be left inthe engine during assembly, or it may passthrough filters or the crankcase ventilation(PCV) system. It may get into the oil, and fromthere into the bearings. Metal chips frommachining operations and normal engine wearare often present. Abrasives are sometimesleft in engine components after recondi-tioning, especially when parts are notthoroughly cleaned using the proper cleaningmethods. Whatever the source, these foreignobjects often end up embedded in the softbearing material, and are easily recognised.Large particles will not embed in the bearing,and will score or gouge the bearing andjournal. The best prevention for this cause ofbearing failure is to clean all parts thoroughly,and to keep everything spotlessly-cleanduring engine assembly. Frequent and regularengine oil and filter changes are alsorecommended.5 Lack of lubrication (or lubricationbreakdown) has a number of interrelatedcauses. Excessive heat (which thins the oil),overloading (which squeezes the oil from thebearing face) and oil “leakage” or “throw off”(from excessive bearing clearances, worn oilpump, or high engine speeds) all contribute tolubrication breakdown. Blocked oil passages,which usually are the result of misaligned oilholes in a bearing shell, will also oil-starve abearing and destroy it. When lack oflubrication is the cause of bearing failure, thebearing material is wiped or extruded from thesteel backing of the bearing. Temperaturesmay increase to the point where the steelbacking turns blue from overheating.6 Driving habits can have a definite effect onbearing life. Full-throttle, low-speed operation(labouring the engine) puts very high loads on

bearings, which tends to squeeze out the oilfilm. These loads cause the bearings to flex,which produces fine cracks in the bearingface (fatigue failure). Eventually, the bearingmaterial will loosen in places, and tear awayfrom the steel backing. Short-trip drivingleads to corrosion of bearings, becauseinsufficient engine heat is produced to driveoff the condensation and corrosive gases.These products collect in the engine oil,forming acid and sludge. As the oil is carriedto the engine bearings, the acid attacks andcorrodes the bearing material.7 Incorrect bearing refitting during engineassembly will lead to bearing failure as well.Tight-fitting bearings leave insufficient bearingoil clearance, and will result in oil starvation.Dirt or foreign particles trapped behind abearing shell result in high spots on thebearing, which will lead to failure.

21 Engine overhaul - reassembly sequence

1 Before beginning engine reassembly, makesure you have all the necessary new parts,gaskets and seals, as well as the followingitems on hand:

Common hand toolsA torque wrenchPiston ring refitting toolPiston ring compressorVibration damper refitting toolShort lengths of rubber or plastic hose to fitover connecting rod bolts (whereapplicable)PlastigageFeeler gaugesA fine-tooth fileNew engine oilEngine assembly oil or molybdenumdisulphide (“moly”) greaseGasket sealantThread-locking compound

2 In order to save time and avoid problems,engine reassembly should be done in thefollowing general order:

Piston ringsCrankshaft and main bearingsPiston/connecting rod assembliesOil pumpSumpCylinder head assemblyTiming belt or chain and tensioner assembliesWater pumpTiming belt or chain coversIntake and exhaust manifoldsValve coverEngine rear plateFlywheel/driveplate

22 Piston rings - refitting 21 Before fitting the new piston rings, the ringend gaps must be checked. It’s assumed thatthe piston ring side clearance has beenchecked and verified (see Section 18).2 Lay out the piston/connecting rodassemblies and the new ring sets, so that thering sets will be matched with the same pistonand cylinder during the end gap measurementand engine assembly.3 Insert the top ring into the first cylinder, andsquare it up with the cylinder walls by pushingit in with the top of the piston (see illustration).The ring should be near the bottom of thecylinder, at the lower limit of ring travel.4 To measure the end gap, slip feeler gaugesbetween the ends of the ring until a gauge equalto the gap width is found (see illustration). Thefeeler gauge should slide between the ring endswith a slight amount of drag. Compare themeasurement to this Chapter’s Specifications.If the gap is larger or smaller than specified,double-check to make sure you have thecorrect rings before proceeding.5 If the gap is too small, it must be enlarged,or the ring ends may come in contact witheach other during engine operation, whichcan cause serious damage to the engine. Theend gap can be increased by filing the ringends very carefully with a fine file. Mount the


22.5 If the end gap is too small, clamp afile in a vice, and file the ring ends (fromthe outside in only) to enlarge the gap

slightly

22.4 With the ring square in the cylinder,measure the end gap with a feeler gauge

22.3 When checking piston ring end gap,the ring must be square in the cylinder

bore (this is done by pushing the ring downwith the top of a piston as shown)

file in a vice equipped with soft jaws, slip thering over the file, with the ends contacting thefile face, and slowly move the ring to removematerial from the ends. When performing thisoperation, file only from the outside in (seeillustration).6 Excess end gap isn’t critical unless it’sgreater than 1.0 mm. Again, double-check tomake sure you have the correct rings for yourengine.7 Repeat the procedure for each ring that willbe fitted in the first cylinder and for each ringin the remaining cylinders. Remember to keeprings, pistons and cylinders matched up.8 Once the ring end gaps have beenchecked/corrected, the rings can be fitted onthe pistons.9 The oil control ring (lowest one on thepiston) is usually fitted first. It’s normallycomposed of three separate components.Slip the spacer/expander into the groove (seeillustration). If an anti-rotation tang is used,make sure it’s inserted into the drilled hole inthe ring groove. Next, refit the lower side rail.Don’t use a piston ring refitting tool on the oilring side rails, as they may be damaged.Instead, place one end of the side rail into thegroove between the spacer/expander and thering land, hold it firmly in place, and slide afinger around the piston while pushing the railinto the groove (see illustration). Next, refitthe upper side rail in the same manner.10 After the three oil ring components havebeen fitted, check to make sure that both theupper and lower side rails can be turnedsmoothly in the ring groove.11 The middle ring is fitted next. It’s usuallystamped with a mark which must face up,towards the top of the piston. Note: Alwaysfollow the instructions printed on the ringpackage or box - different manufacturers mayrequire different approaches. Do not mix upthe top and middle rings, as they havedifferent cross-sections.12 Make sure the identification mark is facingthe top of the piston, then slip the ring into themiddle groove on the piston (see illus-tration 18.2). Don’t expand the ring any morethan necessary to slide it over the piston. Usea proper ring-fitting tool if available; with care,old feeler gauges can be used to prevent therings dropping into empty grooves.

13 Refit the top ring in the same manner.Make sure the mark is facing upwards. Becareful not to confuse the top and middlerings.14 Repeat the procedure for the remainingpistons and rings.

23 Intermediate shaft - refitting 51 Clean the intermediate shaft bearingsurfaces and the pressed-in bearing sleevesin the cylinder block.2 Lubricate the shaft, and slide it into theblock.3 Refit the two bolts that hold the retainingplate to the block.4 The remainder of the parts are fitted in thereverse order of removal.

24 Crankshaft - refitting andmain bearing oil clearancecheck

41 Crankshaft refitting is the first major step inengine reassembly. It’s assumed at this pointthat the engine block and crankshaft havebeen cleaned, inspected, and repaired orreconditioned.2 Position the block upside-down.3 Remove the main bearing cap bolts, and lift

out the caps. Lay them out in the proper orderto ensure correct refitting.4 If they’re still in place, remove the originalbearing shells from the block and the mainbearing caps. Wipe the bearing surfaces ofthe block and caps with a clean, lint-freecloth. They must be kept spotlessly-clean.

Main bearing oil clearancecheck5 Clean the back sides of the new mainbearing shells, and lay one in each mainbearing saddle in the block. If one of thebearing shells from each set has a largegroove in it, make sure the grooved shell isfitted in the block. Lay the other bearing fromeach set in the corresponding main bearingcap. Make sure the tab on the bearing shellfits into the recess in the block or cap.

Caution: The oil holes in theblock must line up with the oilholes in the bearing shell. Do nothammer the bearing into place,

and don’t nick or gouge the bearing faces.No lubrication should be used at this time.6 The flanged thrust bearing must be fitted inthe No 3 bearing cap and saddle in the M10engine, in the No 6 bearing cap and saddle inthe M20 engine (see illustration), in the No 4bearing cap and saddle in the M30 engine,and in the No 4 bearing saddle only in theM40 engine.7 Clean the faces of the bearings in the blockand the crankshaft main bearing journals witha clean, lint-free cloth.8 Check or clean the oil holes in thecrankshaft, as any dirt here can go only oneway - straight through the new bearings.9 Once you’re certain the crankshaft is clean,carefully lay it in position in the main bearings.10 Before the crankshaft can be permanentlyfitted, the main bearing oil clearance must bechecked.11 Cut several pieces of the appropriate-sizePlastigage (they must be slightly shorter thanthe width of the main bearings), and place onepiece on each crankshaft main bearingjournal, parallel with the crankshaft centreline(see illustration).12 Clean the faces of the bearings in thecaps, and refit the caps in their respective


22.9b DO NOT use a piston ring refittingtool when refitting the oil ring side rails

22.9a Refitting the spacer/expander in theoil control ring groove

24.11 Lay the Plastigage strips on themain bearing journals, parallel to the

crankshaft centreline

24.6 Refitting a thrust main bearing (notethe flanges) in the engine block bearing

saddle

2B

positions (don’t mix them up) with the arrowspointing towards the front of the engine. Don’tdisturb the Plastigage.13 Starting with the centre main bearing andworking out toward the ends, progressivelytighten the main bearing cap bolts to thetorque listed in this Chapter’s Specifications.On M10, M20 and M30 engines, tighten thebolts in three stages. On the M40 engine,tighten all the bolts initially to the Stage 1torque, then angle-tighten them by the anglegiven in the Specifications. Carry out theangle-tightening on each bolt in onecontrolled movement. Don’t rotate thecrankshaft at any time during the tighteningoperation.14 Remove the bolts and carefully lift off themain bearing caps. Keep them in order. Don’tdisturb the Plastigage or rotate thecrankshaft. If any of the main bearing caps aredifficult to remove, tap them gently from side-to-side with a soft-face hammer to loosenthem.15 Compare the width of the crushedPlastigage on each journal to the scale printedon the Plastigage envelope to obtain the mainbearing oil clearance (see illustration). Checkthe Specifications to make sure it’s correct.16 If the clearance is not as specified, the

bearing shells may be the wrong size (whichmeans different ones will be required). Beforedeciding that different shells are needed,make sure that no dirt or oil was between thebearing shells and the caps or block when theclearance was measured. If the Plastigagewas wider at one end than the other, thejournal may be tapered (see Section 19).17 Carefully scrape all traces of thePlastigage material off the main bearingjournals and/or the bearing faces. Use yourfingernail or the edge of a credit card - don’tnick or scratch the bearing faces.

Final crankshaft refitting18 Carefully lift the crankshaft out of theengine.19 Clean the bearing faces in the block, thenapply a thin, uniform layer of molybdenumdisulphide (“moly”) grease or engine oil toeach of the bearing surfaces. Be sure to coatthe thrust faces as well as the journal face ofthe thrust bearing.20 Make sure the crankshaft journals areclean, then lay the crankshaft back in place inthe block.21 Clean the faces of the bearings in thecaps, then apply engine oil to them.22 Refit the caps in their respectivepositions, with the arrows pointing towardsthe front of the engine.23 Refit the bolts finger-tight.24 Lightly tap the ends of the crankshaftforward and backward with a lead or brasshammer, to line up the main bearing andcrankshaft thrust surfaces.25 Tighten the bearing cap bolts to thespecified torque, working from the centreoutwards. On M10, M20 and M30 engines,tighten the bolts in three stages to the finaltorque, leaving out the thrust bearing capbolts at this stage. On M40 engines, tighten allof the bolts in the two stages given in theSpecifications.26 On M10, M20 and M30 engines, tightenthe thrust bearing cap bolts to the torquelisted in this Chapter’s Specifications.27 On manual transmission models, fit a newpilot bearing in the end of the crankshaft (seeChapter 8).

28 Rotate the crankshaft a number of timesby hand to check for any obvious binding.29 The final step is to check the crankshaftendfloat with a feeler gauge or a dial indicatoras described in Section 13. The endfloatshould be correct, providing the crankshaftthrust faces aren’t worn or damaged, and newbearings have been fitted.30 Fit the new seal, then bolt the housing tothe block (see Section 25).

25 Crankshaft rear oil seal -refitting 3

1 The crankshaft must be fitted first, and themain bearing caps bolted in place. The newseal should then be fitted in the retainer, andthe retainer bolted to the block.2 Before refitting the crankshaft, check theseal contact surface very carefully forscratches and nicks that could damage thenew seal lip and cause oil leaks. If thecrankshaft is damaged, the only alternative isa new or different crankshaft, unless amachine shop can suggest a means of repair.3 The old seal can be removed from thehousing with a hammer and punch by drivingit out from the back side (see illustration). Besure to note how far it’s recessed into thehousing bore before removing it; the new sealwill have to be recessed an equal amount. Bevery careful not to scratch or otherwisedamage the bore in the housing, or oil leakscould develop.4 Make sure the retainer is clean, then applya thin coat of engine oil to the outer edge ofthe new seal. The seal must be pressedsquarely into the housing bore, so hammeringit into place is not recommended. At the veryleast, use a block of wood as shown, or asection of large-diameter pipe (seeillustration). If you don’t have access to apress, sandwich the housing and sealbetween two smooth pieces of wood, andpress the seal into place with the jaws of alarge vice. The pieces of wood must be thickenough to distribute the force evenly aroundthe entire circumference of the seal. Work


25.5 Lubricate the lip of the seal, and boltthe retainer to the rear of the engine block

25.4 Drive the new seal into the retainerwith a wooden block or a section of pipe, if

you have one large enough - make surethe seal enters the retainer bore squarely

25.3 After removing the retainer from theblock, support it on two wooden blocks,

and drive out the old seal with a punch andhammer

24.15 Compare the width of the crushedPlastigage to the scale on the envelope todetermine the main bearing oil clearance

(always take the measurement at thewidest point of the Plastigage); be sure to

use the correct scale - standard andmetric ones are included

slowly, and make sure the seal enters the boresquarely.5 The seal lips must be lubricated with multi-purpose grease or clean engine oil before theseal/retainer is slipped over the crankshaftand bolted to the block (see illustration). Usea new gasket - no sealant is required - andmake sure the dowel pins are in place beforerefitting the retainer.6 Tighten the retainer nuts/screws a little at atime until they’re all snug, then tighten them tothe torque listed in the Specifications inChapter 2A.

26 Pistons/connecting rods -refitting and big-end bearingoil clearance check

41 Before refitting the piston/connecting rodassemblies, the cylinder walls must beperfectly clean, the top edge of each cylindermust be chamfered, and the crankshaft mustbe in place.2 Remove the cap from the end of No 1connecting rod (refer to the marks madeduring removal). Remove the original bearingshells, and wipe the bearing surfaces of theconnecting rod and cap with a clean, lint-freecloth. They must be kept spotlessly-clean.

Connecting rod big-end bearingoil clearance check3 Clean the back side of the new upperbearing shell, then lay it in place in theconnecting rod. Make sure the tab on thebearing fits into the recess in the rod. Don’thammer the bearing shell into place, and bevery careful not to nick or gouge the bearingface. Don’t lubricate the bearing at this time.4 Clean the back side of the other bearingshell, and refit it in the rod cap. Again, makesure the tab on the bearing fits into the recessin the cap, and don’t apply any lubricant. It’scritically important that the mating surfaces ofthe bearing and connecting rod are perfectly

clean and oil-free when they’re assembled forthis check.5 Position the piston ring gaps so they’restaggered 120° from each other.6 Where applicable, slip a section of plasticor rubber hose over each connecting rod capbolt.7 Lubricate the piston and rings with cleanengine oil, and attach a piston ringcompressor to the piston. Leave the skirtprotruding about 6 or 7 mm to guide thepiston into the cylinder. The rings must becompressed until they’re flush with the piston.8 Rotate the crankshaft until the No 1connecting rod journal is at BDC (bottomdead centre). Apply a coat of engine oil to thecylinder walls.9 With the mark or notch on top of the pistonfacing the front of the engine, gently insert thepiston/connecting rod assembly into the No 1cylinder bore, and rest the bottom edge of thering compressor on the engine block.10 Tap the top edge of the ring compressorto make sure it’s contacting the block aroundits entire circumference.11 Gently tap on the top of the piston withthe end of a wooden hammer handle (seeillustration) while guiding the end of theconnecting rod into place on the crankshaftjournal. Work slowly, and if any resistance isfelt as the piston enters the cylinder, stopimmediately. Find out what’s catching, and fixit before proceeding. Do not, for any reason,force the piston into the cylinder - you mightbreak a ring and/or the piston.

12 Once the piston/connecting rod assemblyis fitted, the connecting rod big-end bearingoil clearance must be checked before the rodcap is permanently bolted in place.

13 Cut a piece of the appropriate-sizePlastigage slightly shorter than the width ofthe connecting rod big-end bearing, and lay it in place on the No 1 connecting rodjournal, parallel with the crankshaft centre-line.14 Clean the connecting rod cap bearingface, remove the protective hoses from theconnecting rod bolts, and refit the rod cap.Make sure the mating mark on the cap is onthe same side as the mark on the connectingrod.15 Refit the nuts/bolts, and tighten them tothe torque listed in this Chapter’s Specifica-tions. On M10 and M30 engines, work up tothe final torque in three stages. Note: Use athin-wall socket, to avoid erroneous torquereadings that can result if the socket iswedged between the rod cap and nut. If thesocket tends to wedge itself between the nutand the cap, lift up on it slightly until it nolonger contacts the cap. Do not rotate thecrankshaft at any time during this operation.16 Undo the nuts and remove the rod cap,being very careful not to disturb thePlastigage.17 Compare the width of the crushedPlastigage to the scale printed on thePlastigage envelope to obtain the oilclearance (see illustration). Compare it to theSpecifications to make sure the clearance iscorrect.18 If the clearance is not as specified, thebearing shells may be the wrong size (whichmeans different ones will be required). Beforedeciding that different shells are needed,make sure that no dirt or oil was between thebearing shells and the connecting rod or capwhen the clearance was measured. Also,recheck the journal diameter. If the Plastigagewas wider at one end than the other, thejournal may be tapered (see Section 19).

Final connecting rod refitting19 Carefully scrape all traces of thePlastigage material off the rod journal and/orbearing face. Be very careful not to scratch


26.17 Measuring the width of the crushed Plastigage todetermine the big-end bearing oil clearance (be sure to use the

correct scale - standard and metric ones are included)

26.11 Drive the piston gently into the cylinder bore with the end ofa wooden or plastic hammer handle

2B

The piston rings may try topop out of the ringcompressor just beforeentering the cylinder bore, so

keep some downward pressure on thering compressor

the bearing - use your fingernail or the edge ofa credit card.20 Make sure the bearing faces are perfectlyclean, then apply a uniform layer ofmolybdenum disulphide (“moly”) grease orengine assembly oil to both of them. You’llhave to push the piston into the cylinder toexpose the face of the bearing shell in theconnecting rod - be sure to slip the protectivehoses over the rod bolts first, whereapplicable.21 Slide the connecting rod back into placeon the journal, and remove the protectivehoses from the rod cap bolts. Refit the rodcap, and tighten the nuts/bolts to thespecified torque.22 Repeat the entire procedure for theremaining pistons/connecting rods.23 The important points to remember are:a) Keep the back sides of the bearing shells

and the insides of the connecting rodsand caps perfectly clean whenassembling them.

b) Make sure you have the correctpiston/rod assembly for each cylinder.

c) The notch or mark on the piston mustface the front of the engine.

d) Lubricate the cylinder walls with clean oil.e) Lubricate the bearing faces when refitting

the rod caps after the oil clearance hasbeen checked.

24 After all the piston/connecting rodassemblies have been properly fitted, rotatethe crankshaft a number of times by hand tocheck for any obvious binding.

25 Check the connecting rod side play (seeSection 13).26 Compare the measured side play to theSpecifications to make sure it’s correct. If itwas correct before dismantling, and theoriginal crankshaft and rods were refitted, itshould still be right. If new rods or a newcrankshaft were fitted, the side play may beincorrect. If so, the rods will have to beremoved and taken to a machine shop forattention.

27 Initial start-up and running-in after overhaul 1

Warning: Have a fire extinguisherhandy when starting the enginefor the first time.

1 Once the engine has been refitted in thevehicle, double-check the engine oil andcoolant levels.2 With the spark plugs removed and theignition system disabled (see Section 3), crankthe engine until oil pressure registers on thegauge, or until the oil pressure warning lightgoes out.3 Refit the spark plugs, connect the HT leads,and restore the ignition system functions (seeSection 3).4 Start the engine. It may take a fewmoments for the fuel system to build up

pressure, but the engine should start withouta great deal of effort. Note: If backfiringoccurs through the throttle body orcarburettor, check the valve timing (check thatthe timing chain/belt has been correctly fitted),the firing order (check the fitted order of thespark plug HT leads), and the ignition timing.5 After the engine starts, it should be allowedto warm up to normal operating temperature.While the engine is warming up, make athorough check for fuel, oil and coolant leaks.6 Shut the engine off and recheck the engineoil and coolant levels.7 Drive the vehicle to an area with minimumtraffic, accelerate at full throttle from 30 to 50 mph, then lift off the throttle completely,and allow the vehicle to slow to 30 mph withthe throttle closed. Repeat the procedure 10 or 12 times. This will load the piston rings,and cause them to seat properly against thecylinder walls. Check again for oil and coolantleaks.8 Drive the vehicle gently for the first 500 miles (no sustained high speeds) andkeep a constant check on the oil level. It is notunusual for an engine to use oil during therunning-in period.9 At approximately 500 to 600 miles, changethe oil and filter.10 For the next few hundred miles, drive thevehicle normally - don’t nurse it, but don’tabuse it, either.11 After 2000 miles, change the oil and filteragain. The engine may now be considered tobe fully run-in.


3GeneralCoolant capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Thermostat rating

Opening temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80°C (176°F)Fully open at . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100°C (212°F)

Cooling fan thermo-switch - switching temperaturesLow-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91°C (196°F)High-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99°C (210°F)

Torque wrench settings NmMechanical cooling fan clutch-to-water pump securing

nut (left-hand thread) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Mechanical cooling fan-to-clutch bolts . . . . . . . . . . . . . . . . . . . . . . . . . 10Water pump bolts

Small bolts (M6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Large bolts (M8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Thermostat housing bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 3Cooling, heating and air conditioning systems

Air conditioner receiver-drier - removal and refitting . . . . . . . . . . . . 16Air conditioning blower motor (E28/”old-shape” 5-series

models) - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Air conditioning compressor - removal and refitting . . . . . . . . . . . . . 13Air conditioning condenser - removal and refitting . . . . . . . . . . . . . . 15Air conditioning system - precautions and maintenance . . . . . . . . . 12Antifreeze - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Coolant level check . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Coolant temperature sender unit - check and renewal . . . . . . . . . . . 8Cooling system check . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Cooling system servicing (draining, flushing and refilling)See Chapter 1

Engine cooling fan(s) and clutch - check, removal and refitting . . . . 5Evaporator matrix - removal and refitting . . . . . . . . . . . . . . . . . . . . . 17General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Heater and air conditioner control assembly - removal and refitting 10Heater and air conditioning blower motor - removal,testing and

refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Heater matrix - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 11Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Thermostat - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Water pump - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Water pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 7

3•1







Specifications

Contents


Engine cooling systemAll vehicles covered by this manual employ

a pressurised engine cooling system, withthermostatically-controlled coolant circulation.

An impeller-type water pump mounted onthe front of the block pumps coolant throughthe engine. The coolant flows around eachcylinder, and towards the rear of the engine.Cast-in coolant passages direct coolant

around the intake and exhaust ports, near thespark plug areas, and in close proximity to theexhaust valve guides.

A wax-pellet-type thermostat is located in-line in the bottom hose on M10 engines, in ahousing near the front of the engine on M20and M30 engines, or behind an elbow underthe timing belt upper cover (on the front of thecylinder head) on M40 engines. During warm-up, the closed thermostat prevents coolantfrom circulating through the radiator. As theengine nears normal operating temperature,the thermostat opens and allows hot coolantto travel through the radiator, where it’scooled before returning to the engine.

The pressure in the system raises theboiling point of the coolant, and increases thecooling efficiency of the radiator. The coolingsystem is sealed by a pressure-type cap. Ifthe system pressure exceeds the cappressure relief value, the excess pressure inthe system forces the spring-loaded valveinside the cap off its seat, and allows thecoolant to escape through the overflow tube.

The pressure cap on four-cylinder models ison the top of the radiator; on six-cylinder models,it’s on top of a translucent plastic expansiontank. The cap pressure rating is moulded into thetop of the cap. The pressure rating is either 1.0 bar (14 psi) or 1.2 bars (17 psi).

Warning: Do not remove thepressure cap from the radiator orexpansion tank until the enginehas cooled completely and

there’s no pressure remaining in thecooling system. Removing the cap from ahot engine risks personal injury byscalding.

Heating systemThe heating system consists of a blower fan

and heater matrix located in the heater box,with hoses connecting the heater matrix to theengine cooling system, and the heater/airconditioning control head on the dashboard.Hot engine coolant is circulated through theheater matrix passages all the time the engineis running. Switching the heater on opens aflap door to direct air through the heatermatrix, and the warmed air enters thepassenger compartment. A fan switch on thecontrol head activates the blower motor,which forces more air through the heatermatrix, giving additional heater output fordemisting, etc.

Air conditioning systemThe air conditioning system consists of a

condenser mounted in front of the radiator, anevaporator mounted adjacent to the heatermatrix, a compressor mounted on the engine,a filter-drier (receiver-drier) which contains ahigh-pressure relief valve, and the plumbingconnecting all of the above components.

A blower fan forces the warmer air of thepassenger compartment through theevaporator matrix (a radiator-in-reverse),transferring the heat from the air to therefrigerant. The liquid refrigerant boils off intolow-pressure vapour, taking the heat with itwhen it leaves the evaporator.

Note: Refer to the precautions at the startof Section 12 concerning the potentialdangers associated with the air conditioningsystem.

2 Antifreeze - general information

Warning: Do not allow antifreezeto come in contact with your skinor painted surfaces of thevehicle. Rinse off spills

immediately with plenty of water. Ifconsumed, antifreeze can be fatal;children and pets are attracted by itssweet taste, so wipe up garage floor anddrip pan coolant spills immediately. Keepantifreeze containers covered, and repairleaks in your cooling system as soon asthey are noticed.

The cooling system should be filled with a60/40% water/ethylene-glycol-based anti-freeze solution, which will prevent freezingdown to approximately -27°C (-17°F). Theantifreeze also raises the boiling point of the

coolant, and (if of good quality) providesprotection against corrosion.

The cooling system should be drained,flushed and refilled at the specified intervals(see Chapter 1). Old or contaminatedantifreeze solutions are likely to causedamage, and encourage the formation of rustand scale in the system. Use distilled waterwith the antifreeze, if available, or cleanrainwater. Tap water will do, but not if thewater in your area is at all “hard”.

Before adding antifreeze, check all hoseconnections, because antifreeze tends tosearch out and leak through very minuteopenings. Engines don’t normally consumecoolant, so if the level goes down, find thecause and correct it.

The antifreeze mixture should bemaintained at its correct proportions; addingtoo much antifreeze reduces the efficiency ofthe cooling system. If necessary, consult themixture ratio chart on the antifreeze containerbefore adding coolant. Hydrometers areavailable at most car accessory shops to testthe coolant. Use antifreeze which meets thevehicle manufacturer’s specifications.

3 Thermostat - check and renewal 1

Warning: Do not remove theradiator cap, drain the coolant, orrenew the thermostat until theengine has cooled completely.

Check1 Before assuming the thermostat is to blamefor a cooling system problem, check thecoolant level, drivebelt tension (see Chapter 1)and temperature gauge (or warning light)operation.2 If the engine seems to be taking a long timeto warm up (based on heater output ortemperature gauge operation), the thermostatis probably stuck open. Renew thethermostat.3 If the engine runs hot, use your hand tocheck the temperature of the upper radiatorhose. If the hose isn’t hot, but the engine is,the thermostat is probably stuck closed,

preventing the coolant inside the engine fromcirculating to the radiator. Renew thethermostat.

Caution: Don’t drive the vehiclewithout a thermostat. The enginewill be very slow to warm-up incold conditions, resulting in poor

fuel economy and driveability. A newthermostat is normally an inexpensivecomponent anyway.4 If the upper radiator hose is hot, it meansthat the coolant is flowing and the thermostatis at least partly open. Consult the “Faultfinding” Section at the rear of this manual forcooling system diagnosis.

RenewalAll models5 Disconnect the negative cable from thebattery.


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.6 Drain the cooling system (see Chapter 1). Ifthe coolant is relatively new or in goodcondition, save it and re-use it.M10 engines7 The thermostat is located in the bottomhose. First remove the cooling fan.8 Note the fitted position of the thermostat,then unscrew the hose clamps and withdrawthe thermostat from the hose connections(see illustration).9 Refit the thermostat-to-hose connections,and tighten the hose clamps.10 Refit the cooling fan.

M20 and M30 engines11 Loosen the hose clamp (see illustration),then detach the hose(s) from the thermostatcover.

3•2 Cooling, heating and air conditioning systems

3.11 On M20 and M30 engine models,loosen the hose clamp (A) and disconnect

the hose from the thermostat housingcover - note that the coolant temperaturesender unit (barely visible behind the fuel

pressure regulator) is located at the top ofthe thermostat housing (B)

3.8 On the M10 (four-cylinder) engine, thethermostat (arrowed) is connected in-line

in the radiator hose

12 If the outer surface of the fitting thatmates with the hose is deteriorated (corroded,pitted, etc.), it may be damaged further byhose removal. If it is, a new thermostathousing cover will be required.13 Remove the bolts and detach the housingcover. If the cover is stuck, tap it with a soft-faced hammer to jar it loose. Be prepared forsome coolant to spill as the gasket seal isbroken.14 Note how it’s fitted, then remove thethermostat.15 Stuff a rag into the engine opening, thenremove all traces of old gasket material (if thegasket is paper type). Otherwise, remove therubber O-ring (see illustration) and sealantfrom the housing and cover with a gasketscraper. Remove the rag from the openingand clean the gasket mating surfaces.16 Fit the new thermostat and gasket in thehousing. Make sure the correct end faces out- the spring end is normally directed towardsthe engine.17 Refit the cover and bolts. Tighten thebolts to the torque listed in this Chapter’sSpecifications.

M40 engines18 Remove the cooling fan and timing beltupper cover.19 Unscrew the hose clamp and detach the

bottom hose from the elbow on the front ofthe cylinder head.20 Unbolt the elbow from the cylinder head.Note the fitted position of the thermostat, thenremove it (see illustrations). Remove therubber O-ring; a new one will be needed forreassembly.21 Locate the thermostat in the cylinder headin the same position as noted during removal(arrow pointing upwards).22 Press a new O-ring in the groove, andlocate the elbow on the cylinder head. Tightenthe bolts.23 Connect the bottom hose to the elbow,and tighten the hose clamp.24 Refit the upper timing belt cover andcooling fan.

All models25 Refill the cooling system (see Chapter 1).26 Connect the battery negative cable.27 Start the engine and allow it to reachnormal operating temperature, then check forleaks and proper thermostat operation (asdescribed earlier in this Section).

4 Radiator - removal and refitting 1

Warning: Wait until the engine iscompletely cool before beginningthis procedure.

Note: If the radiator is being removed becauseit is leaking, note that minor leaks can often berepaired without removing the radiator, usinga radiator sealant.



Removal1 Disconnect the battery negative cable. 2 Drain the cooling system (see Chapter 1). Ifthe coolant is relatively new, or in goodcondition, save it and re-use it.3 Loosen the hose clamps, then detach thehoses from the radiator (see illustrations). Ifthey’re stuck, grasp each hose near the endwith a pair of water pump pliers, twist gentlyto break the seal, then pull off - be careful notto distort or break the radiator outlets! If thehoses are old or deteriorated, cut them offand refit new ones.4 On M20 and M30 engines, disconnect thereservoir hose from the radiator filler neck.5 Remove the screws or plastic fasteners thatattach the shroud to the radiator, and slide theshroud towards the engine (see illustration).On some engines it is possible to completelyremove the shroud.6 If the vehicle has automatic transmission,

Cooling, heating and air conditioning systems 3•3

3.20b Removing the thermostat (M40 engine)

3.20a Removing the elbow from thecylinder head (M40 engine)

3.15 On M20 and M30 engine models,after the housing and thermostat have

been removed, take the O-ring out of thehousing and clean the recess in the

housing to be sure of a good seal uponreassembly

4.5 Plastic fastener retaining the radiatorshroud on some engines

4.3b Bottom hose connection to theradiator

4.3a Disconnecting the top hose from theradiator

3

disconnect the fluid cooler lines from theradiator. Use a drip tray to catch spilled fluid.Plug the fluid cooler lines and fittings.7 Disconnect the coolant sensors located onthe radiator (see illustration). The thermo-statically-controlled switches for high- andlow-speed operation of the auxiliary fan arelocated in the radiator tanks, in variouslocations depending on engine and model.8 Remove the radiator mounting bolt(s). Themountings are either on the top or sides of theradiator (see illustration).9 Carefully lift out the radiator from thebottom mountings, taking care not to damagethe cooling fins. Don’t spill coolant on thevehicle, or scratch the paint.10 With the radiator removed, it can beinspected for leaks and damage. If it needsrepair, have a specialist perform the work, asspecial techniques are required.11 Flies and dirt can be removed from theradiator with compressed air and a soft brush.Don’t bend the cooling fins as this is done.12 Check the radiator mountings fordeterioration, and renew if necessary (seeillustration).

Refitting13 Refitting is the reverse of the removalprocedure.14 After refitting, fill the cooling system withthe proper mixture of antifreeze and water.Refer to Chapter 1 if necessary.

15 Start the engine and check for leaks.Allow the engine to reach normal operatingtemperature, indicated by the upper radiatorhose becoming hot. Recheck the coolantlevel, and add more if required.16 If you’re working on an automatictransmission model, check and addtransmission fluid as needed.

5 Engine cooling fan(s) andclutch - check, removal andrefitting

1Warning: To avoid possible injuryor damage, DO NOT operate theengine with a damaged fan. Donot attempt to repair fan blades -

fit a new fan. Also, the electric auxiliary fanin front of the radiator or air conditioningcondenser can come on without theengine running or ignition being on. It iscontrolled by the coolant temperature ofthe thermo-switches located in theradiator.

CheckElectric auxiliary fanNote : This fan on most models is controlledby two thermo-switches placed in the radiator:one for low-speed/low-temperature operation,and one for high-speed/high-temperatureoperation. Each switch comes on at a differentcoolant temperature (refer to the Specifica-tions at the beginning of this Chapter). 1 The thermostatically-controlled switches forhigh- and low-speed operation of the auxiliaryfan are fitted in various locations in theradiator (see illustration 4.7), depending onengine or model. Two single switches, or onedual switch, may be fitted.2 Insert a small screwdriver into theconnector to lift the lock tab, and unplug thefan wire harness.3 To test the fan motor, unplug the electricalconnector at the motor, and use jumper wiresto connect the fan directly to the battery. If thefan doesn’t work when connected directly tothe battery, the motor is proved faulty, andmust be renewed. If the fan works, there’s a

good chance the switch is malfunctioning. Tomore accurately diagnose the problem, followthe steps that apply to your model. Note: Spinthe auxiliary fan motor by hand, to check thatthe motor or fan isn’t binding. Make sure,however, that the engine is sufficiently coolthat there is no danger of the fan cutting-in onits own when this is done.4 To test the low-speed and high-speedcircuits, disconnect the electrical connectorfrom one of the fan switches, and bridge theterminals of the switch’s electrical connectorwith a short piece of wire. The fan should runat low or high speed, depending on whichswitch has been disconnected. On somemodels the ignition must be on before the fanwill run.5 Repeat the test at the other switch so thatboth high and low speeds are tested.6 If the low-speed and high-speed circuitsare OK, but there has been a problem with thefan not operating correctly in service, renewthe switch (or switches). To remove a switch,drain the coolant below the level of the switch(see Chapter 1), then unscrew the switch andscrew in the new one. Refill the system withcoolant.7 If the switches are satisfactory, but themotor still does not operate, the problem liesin the fuse, the relay, the wiring whichconnects the components (or the fan motoritself). Carefully check the fuse, relay, allwiring and connections. See Chapter 12 formore information on how to carry out thesechecks.

Mechanical fan with viscous clutch8 Disconnect the battery negative cable, androck the fan back and forth by hand to checkfor excessive bearing play.


before disconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.9 With the engine cold, turn the fan blades byhand. The fan should turn with slightresistance.10 Visually inspect for substantial fluidleakage from the fan clutch assembly. Ifproblems are noted, renew the fan clutchassembly.11 With the engine completely warmed up,turn off the ignition switch and disconnect thebattery negative cable. Turn the fan by hand.Heavier resistance should be evident. If thefan turns easily, a new fan clutch may beneeded.

Removal and refitting

Electric auxiliary fan12 Disconnect the battery negative cable.13 To remove the auxiliary fan follow theprocedure that applies to your vehicle.


4.12 When the radiator is out, the radiatormountings can be inspected - check for

signs of deterioration, and renew them, ifneeded

4.8 The radiator is bolted to the frontpanel at either the sides or the top of the

radiator

4.7 Sensors that control the high- andlow-speed operation of the auxiliary

cooling fan are located in various places inthe radiator tanks

3-Series models14 Remove the radiator grille assembly (seeChapter 11).15 Unbolt and remove the fan bracket andshroud assembly from the radiator (seeSection 5).16 Remove the radiator (see Section 4).17 Unbolt the air conditioning condensermounting bolts, where applicable. Do notremove the condenser or disconnect anyrefrigerant lines from the condenser.18 Carefully pull the condenser back towardsthe engine, slightly, to gain access to lift theauxiliary fan.19 Disconnect the fan motor electricalconnection and remove the auxiliary fan.20 Refitting is the reverse of removal.

5-Series models21 Remove the screws and trim panel in frontof the radiator.22 Unbolt the fan assembly from thecondenser mounting points.23 Disconnect the fan electrical connector.24 Remove the fan and housing from the car,being careful not to damage the airconditioning condenser (when applicable)while removing the fan.25 Refitting is the reverse of removal.

Mechanical fan with viscous clutch26 Disconnect the battery negative cable.Remove the fan shroud mounting screws orplastic fasteners, and detach the shroud (seeSection 4).27 Use a 32 mm open-ended spanner toremove the fan/clutch assembly. Place thespanner on the large nut ahead of the pulley(see illustrations), and tap the end of thespanner to loosen the nut.

Caution: The nut has left-handedthreads, so it loosens by beingturned clockwise, as viewed fromthe front of the vehicle.

28 Lift the fan/clutch assembly (and shroud,if necessary) out of the engine compartment.29 If necessary, remove the four boltsattaching the pulley to the water pump hub.The pulley can then be removed afterremoving the drivebelt(s) (see illustration).

30 Carefully inspect the fan blades fordamage and defects. Renew it if necessary.31 At this point, the fan may be unboltedfrom the clutch, if necessary. If the fan clutchis stored, position it with the radiator sidefacing down.32 Refitting is the reverse of removal.

6 Water pump - check 11 A failure in the water pump can causeserious engine damage due to overheating.2 There are two ways to check the operationof the water pump while it’s fitted on theengine. If either of the following checkssuggest that the pump is defective, a new oneshould be fitted.3 Water pumps are equipped with “weep” or“vent” holes. If a failure occurs in the pumpseal, coolant will leak from the hole. In mostcases, you’ll need a torch to find the hole onthe water pump from underneath to check forleaks.4 If the water pump shaft bearings fail, theremay be a howling sound at the front of theengine while it’s running. Shaft wear can befelt if the water pump pulley is rocked up anddown (with the drivebelt removed). Don’tmistake drivebelt slippage, which causes asquealing sound, for water pump bearingfailure. Alternator bearing failure can alsocause a howling sound, but after removing thedrivebelt(s) it should be easy enough to tellwhich component is responsible.

7 Water pump - removal and refitting 2




Removal1 Disconnect the battery negative cable. 2 Drain the cooling system (see Chapter 1). Ifthe coolant is relatively new, or in goodcondition, save it and re-use it.3 Remove the cooling fan shroud (seeSection 5).4 Remove the drivebelts (see Chapter 1).5 Where applicable, loosen the clamps anddetach the hoses from the water pump. Ifthey’re stuck, grasp each hose near the endwith a pair of water pump pliers and gentlytwist it to break the seal, then pull it off. If thehoses are deteriorated, cut them off and refitnew ones.6 Remove the fan and clutch assembly andthe pulley at the end of the water pump shaft(see Section 5).7 To remove the water pump, follow thespecific steps that apply to your engine.

M10 engine8 Unscrew the mounting bolts and removethe water pump (see illustration).


5.29 Removing the water pump pulley(M40 engine)

5.27b . . . to loosen the nut, place a 32 mmopen-ended spanner on the nut, and

sharply strike the spanner (A) with a metaldrift (B) and hammer; this will loosen thenut and allow it to be turned easily so the

fan can be removed

5.27a The cooling fan on the water pumpis attached to the shaft by a left-hand-

threaded nut located directly behind thefan . . .

7.8 On M10 engines, there are seven bolts(locations arrowed) that hold the water

pump to the block

3

M20 engine9 Remove the distributor cap and HT leads,ignition rotor and dust shield (see Chapter 1).10 Where applicable, remove the timingsensor (see Chapter 5).11 Remove the timing belt upper cover (seeChapter 2A).12 Loosen all three water pump mountingbolts. Remove the top and right-hand sidebolts, but DON’T remove the lower bolt (seeillustration).13 Rotate the pump downwards, and removethe drivebelt tensioner spring and pin. 14 Remove the final water pump bolt, andremove the pump.

Caution: Leave the tensioner bolttight. Be careful to not move thecamshaft gear, as damage canoccur if the valves are moved.

M30 engine15 Remove the engine lifting bracket.16 Remove the bolts that mount the waterpump to the engine block.17 Remove the water pump, and recover thegasket.

M40 engine18 Unscrew the mounting bolts and removethe water pump. If the pump is tight in thecylinder head, insert two bolts in the speciallugs at the top and bottom of the pump, andtighten them evenly to press the pump out ofthe head (see illustrations).

Refitting19 Clean the bolt threads and the threadedholes in the engine to remove corrosion andsealant.20 Compare the new pump to the old one, tomake sure they’re identical.21 Remove all traces of old gasket materialfrom the engine with a gasket scraper.22 Clean the water pump mating surfaces.23 On the M40 engine, locate a new O-ringon the pump (see illustration).24 Locate the gasket on the pump, and offerthe pump up to the engine (see illustration).Slip a couple of bolts through the pumpmounting holes to hold the gasket in place.25 Carefully attach the pump and gasket tothe engine, threading the bolts into the holesfinger-tight. Note: On the M20 engine, refit thelower bolt finger-tight, then rotate the waterpump into position with the drivebelt tensionerspring and pin in position.26 Refit the remaining bolts (if they also holdan accessory bracket in place, be sure toreposition the bracket at this time). Tightenthem to the torque listed in this Chapter’sSpecifications, in quarter-turn increments.Don’t overtighten them, or the pump may bedistorted.27 Refit all parts removed for access to thepump.28 Refill the cooling system and check thedrivebelt tension (see Chapter 1). Run theengine and check for leaks.

8 Coolant temperature senderunit - check and renewal 2


1 The coolant temperature indicator systemis composed of a temperature gaugemounted in the instrument panel, and acoolant temperature sender unit that’snormally mounted on the thermostat housing(see illustration 3.11). Some vehicles havemore than one sender unit, but only one isused for the temperature gauge. On the M40engine, the sender unit is mounted on the left-hand side of the cylinder head, towards therear.2 If the gauge reading is suspect, first checkthe coolant level in the system. Make sure thewiring between the gauge and the sendingunit is secure, and that all fuses are intact. (Ifthe fuel gauge reading is suspect as well, theproblem is almost certainly in the instrumentpanel or its wiring.)3 Before testing the circuit, refer to therelevant wiring diagrams (see Chapter 12).Where the sender unit simply earths out thecircuit, test by earthing the wire connected tothe sending unit while the ignition is on (butwithout the engine running, for safety). If thegauge now deflects to the end of the scale,renew the sender unit. If the gauge does notrespond satisfactorily, the gauge, or the wiringto the gauge, is faulty. Where the sender unithas two terminals, test the circuit by checkingthe resistance of the unit. No figures wereavailable at the time of writing, but typicallyreadings of several hundred or severalthousand ohms (depending on temperature)would be expected. A reading of zero (short-circuit) or infinity (open-circuit) would indicatea faulty sender unit.

Caution: Do not earth the wirefor more than a second or two, ordamage to the gauge couldoccur.


7.24 New outer gasket on the M40 enginewater pump

7.23 Fit a new O-ring on the M40 enginewater pump

7.18b . . . and remove the water pump(M40 engine)

7.18a With the water pump mounting boltsremoved, screw two bolts into the special

lugs (one top and one bottom) . . .

7.12 Water pump bolt locations on theM20 engine

4 If a new sender unit is to be fitted, makesure the engine is completely cool. There willbe some coolant loss when the unit isunscrewed, so be prepared to catch it, orhave the new unit ready to fit immediately theold one is removed. Disconnect the wiring,then unscrew the old unit from the engine,and fit the new one. Use sealant on thethreads. Reconnect the wiring, and check thecoolant level on completion.

9 Heater and air conditioningblower motor - removal,testing and refitting

1RemovalNote: The 3-Series models covered by thismanual have always used a single blowermotor for ventilation, heating and airconditioning. “Old-shape” (E28) 5-Seriesmodels use two separate blower motors: onefor ventilation and heating, and another for airconditioning. “New-shape” (E34) 5-Seriesmodels have a single blower motor, like the 3-Series. The removal and refitting of the singleblower motor, and the old-shape 5-Seriesvent/heat motor, is described below. Theremoval and refitting of the old-shape 5-Seriesair conditioning blower motor is described inSection 14 of this Chapter.


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable. 2 The blower motor is located behind thebulkhead, under an access panel. Remove thepanel securing screws (see illustrations).3 Disconnect or cut the plastic ties holdingthe wiring harness to the panel, and move thewiring out of the way.4 Remove the panel. 5 Unclip the blower housing retaining clip,and the clip securing the blower motor (seeillustrations).

6 Disconnect the wiring and remove theblower motor (see illustration).

Testing7 You can test the blower motor by applyingbattery voltage to the blower motor’sterminals with fused jumper wires (be sure thefan blades won’t hit anything when theyrotate). If the blower motor spins the fanblades rapidly (this test simulates high-speedoperation), the blower motor is OK. If theblower motor does not operate, or operatesslowly or noisily, renew it.Note: If the fan blade assemblies need to beremoved, mark their relationship to the shaft.The assemblies are balanced duringproduction, and excessive noise or shortenedbearing life could result if they are not refittedin exactly the same position in relation to theshaft.

Refitting8 Refitting is the reverse of removal. Note:The blower motor may have to be rotated toallow the retaining clip to line up correctly.

10 Heater and air conditionercontrol assembly - removaland refitting

1Removal1 Disconnect the battery negative cable.



3-Series models2 Remove the centre console and side trimpieces.3 Remove the radio (see Chapter 12), thenpull the knobs off the heater/air conditioningcontrol levers.4 Remove the heater trim panel to gainaccess to the control cables.5 Disconnect the cables, marking them foraccurate refitting.6 Disconnect the electrical connector. 7 Remove the lever assembly.8 Each lever assembly can be removedseparately.

5-Series models9 Remove the centre console (see Chap-ter 11).10 Remove the radio (see Chapter 12), thenpull the knobs off the heater/air conditioningcontrol levers.11 Remove the trim bezel, and pull thecontrol unit from the dash. This will allow youto disconnect the control cables from thelever assembly.


9.5a Unclip the retaining strap to removethe blower housing . . .

9.2b . . . a fastener from the top secure thepanel

9.2a To get to the heater blower motor,the access panel must be removed - a

fastener from the front and . . .

9.6 Lift out the assembly, and disconnectthe electrical connection from the blower

motor9.5b . . . and unclip the centre strap that

secures the blower motor assembly

3

12 Disconnect the cables from the clipssecuring them to the lever assembly, markingthem for accurate refitting.13 Disconnect the electrical connection fromthe control assembly.14 Remove the screws attaching the bezel tothe control assembly, and remove the controlassembly.

Refitting15 Refitting is the reverse of the removalprocedure.

11 Heater matrix - removal and refitting 1


Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable. 2 Drain the cooling system (see Chapter 1).3 Remove the centre console (see Chap-ter 11). Spread an old blanket over the frontcarpeting; this will prevent stains if anyresidual coolant spills.

Removal

3-Series models4 Remove the left-hand side heater ducting,and set it aside.5 Remove the heater valve clamp.6 Remove the screws and detach the flangewhere the two coolant lines enter the heatermatrix case. Be careful; some coolant mayspill.7 Remove the two screws holding the heatermatrix case to the heater main assembly.8 Slide the heater matrix out of the mounting.Be careful not to spill any of the remainingcoolant in the heater matrix when removing it.

5-Series models9 Disconnect the temperature sensorelectrical connectors.10 Disconnect the straps holding the wiringto the case, and set the wiring out of the way.11 Unfasten the cover fasteners.12 Remove the screws holding the cover inplace, then remove the cover.13 Disconnect all heater pipe connectionsattached to the heater matrix. Be careful;some coolant may spill.14 Lifting on the right side of the heatermatrix first, remove the heater matrix.

RefittingNote: Always use new O-rings when attachingthe coolant lines to the heater matrix.

15 Refitting is the reverse of removal. Refillthe cooling system (see Chapter 1), then runthe engine with the heater on, and check forcorrect operation and leaks.

12 Air conditioning system -precautions and maintenance 1

PrecautionsWarning: The air conditioningsystem is under high pressure.DO NOT loosen any hose or linefittings, or remove any

components, until after the system hasbeen discharged. Air conditioningrefrigerant should be properly dischargedby a qualified refrigeration engineer. Therefrigerant used in the system must not beallowed into contact with your skin oreyes, or there is a risk of frostbite. Shouldthe refrigerant come into contact with anaked flame, a poisonous gas will beproduced. Smoking in the presence ofrefrigerant is therefore highly dangerous,particularly if refrigerant vapour is inhaledthrough a lighted cigarette. The refrigerantis heavier than air, and it may causesuffocation if discharged in an enclosedspace such as a domestic garage. Finally, uncontrolled release of therefrigerant causes environmental damage,by contributing to the “greenhouseeffect”.

Maintenance1 The following maintenance checks shouldbe performed on a regular basis to ensure theair conditioner continues to operate at peakefficiency:a) Check the drivebelt. If it’s worn or

deteriorated, renew it (see Chapter 1).b) Check the system hoses. Look for cracks,

bubbles, hard spots and deterioration.Inspect the hoses and all fittings for oilbubbles and seepage. If there’s anyevidence of wear, damage or leaks, havenew hose(s) fitted.

c) Inspect the condenser fins for leaves, fliesand other debris. Use a “fin comb” orcompressed air to clean the condenser.

d) Make sure the system has the correctrefrigerant charge, as described below.

2 It’s a good idea to operate the system forabout 10 minutes at least once a month,particularly during the winter. Long-term non-use can cause hardening, and subsequentfailure, of the seals.3 Because of the complexity of the airconditioning system and the specialequipment necessary to service it, in-depthfault diagnosis and repair procedures are notincluded in this manual. However, simplechecks and component renewal proceduresare provided in this Chapter.4 The most common cause of poor cooling is

simply a low system refrigerant charge. If anoticeable loss of cool air output occurs, thefollowing quick check may help you determineif the refrigerant level is low.5 Warm the engine up to normal operatingtemperature.6 Set the air conditioning temperatureselector at the coldest setting, and put theblower at the highest setting. Open the doors(to make sure the air conditioning systemdoesn’t switch off as soon as it cools thepassenger compartment).7 With the compressor engaged - thecompressor clutch will make an audible click,and the centre of the clutch will rotate - feelthe tube located adjacent to the right frontframe rail, near the radiator.8 If a significant temperature drop is noticed,the refrigerant level is probably OK.9 If the inlet line has frost accumulation, orfeels cooler than the receiver-drier surface,the refrigerant charge is low. Recharging thesystem should be carried out by a qualifiedrefrigeration engineer.

13 Air conditioning compressor- removal and refitting 5

Warning: Due to the potentialdangers associated with thesystem, you are strongly advisedto have any work on the air

conditioning system carried out by a BMWdealer or air conditioning specialist. At thevery least, DO NOT dismantle any part ofthe system (hoses, compressor, linefittings, etc.) until after the system hasbeen discharged by a qualified engineer.Refer to the precautions given at the startof Section 12.Note: If a new compressor is fitted, thereceiver-drier (see Section 16) should also berenewed.

Removal1 Have the air conditioning systemdischarged (see Warning above).2 Disconnect the battery negative cable.



3 Disconnect the compressor clutch wiringharness.4 Remove the drivebelt (see Chapter 1).5 Disconnect the refrigerant lines from therear of the compressor. Plug the open fittingsto prevent entry of dirt and moisture.6 Unbolt the compressor from the mounting


brackets, and lift it up and out of the vehicle(see illustration).

Refitting7 If a new compressor is being fitted, followany instructions supplied with the compressorregarding the draining of excess oil prior tofitting.8 The clutch may have to be transferred tothe new compressor.9 Refitting is the reverse of removal. All O-rings should be replaced with new onesspecifically made for use in air conditioningsystems. Lubricate them with refrigerant oilwhen fitting.10 Have the system evacuated, rechargedand leak-tested by the qualified engineer whodischarged it.

14 Air conditioning blower motor(E28/“old-shape” 5-seriesmodels) - removal and refitting

1Note: Refer to Section 9 for information on“new-shape” (E34) 5-Series models.



Removal1 Disconnect the battery negative cable. 2 Remove the centre console (see Chap-ter 11).3 Disconnect the blower motor electricalconnector from the motor.4 Unbolt the blower motor mountings fromthe main case.5 Remove the air conditioning blower motorassembly. You can check the motor byfollowing the procedure described in Sec-tion 9.

Refitting6 Refitting is the reverse of removal.

15 Air conditioning condenser -removal and refitting 5


conditioning system carried out by a BMWdealer or air conditioning specialist. At thevery least, DO NOT dismantle any part ofthe system (hoses, compressor, linefittings, etc.) until after the system hasbeen discharged by a qualified engineer.Refer to the precautions given at the startof Section 12.

Note: If a new condenser is fitted, thereceiver-drier (see Section 16) should also berenewed.

Removal1 Have the air conditioning systemdischarged (see Warning above).2 Remove the radiator (see Section 4) excepton “new-shape” (E34) 5-series models. On thelatter, remove the front bumper (see Chap-ter 11).3 Remove the radiator grille (see Chapter 11).4 Unbolt the auxiliary fan from the airconditioning condenser mounting brackets.5 Disconnect the refrigerant lines from thecondenser.6 Remove the mounting bolts from thecondenser brackets.7 Lift the condenser out of the vehicle, andplug the lines to keep dirt and moisture out.8 If the original condenser is being refitted,store it with the line fittings uppermost, toprevent oil from draining out.

Refitting9 Refit the components in the reverse orderof removal. Be sure the rubber pads are inplace under the condenser.10 Have the system evacuated, rechargedand leak-tested by the qualified engineer whodischarged it.

16 Air conditioner receiver-drier- removal and refitting 5


conditioning system carried out by a BMWdealer or air conditioning specialist. At thevery least, DO NOT dismantle any part ofthe system (hoses, compressor, linefittings, etc.) until after the system hasbeen discharged by a qualified engineer.Refer to the precautions given at the startof Section 12.

Removal1 Have the system discharged (see Warningabove).2 Disconnect the battery negative cable.


before disconnecting the battery.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.3 Remove the windscreen washer fluidreservoir.4 Disconnect the electrical connector(s) fromthe receiver-drier - note that not all modelshave both the high- and low-pressureswitches (see illustration).5 Disconnect the refrigerant lines from thereceiver-drier.6 Plug the open line fittings, to prevent theentry of dirt and moisture.7 Remove the mounting screws and removethe receiver-drier.

Refitting8 If a new receiver-drier is being fitted, it maybe necessary to add a quantity of refrigerantoil - follow the instructions supplied with thenew unit.9 Remove the old refrigerant line O-rings, andfit new ones. This should be done regardlessof whether a new receiver-drier is being fitted.10 If a new receiver-drier is being fitted,unscrew the pressure switches and transferthem to the new unit before fitting (seeillustration 16.4). Not all models have boththe high- and low-pressure switches.11 Lubricate the O-rings with refrigerant oilbefore assembly.

Refitting12 Refitting is the reverse of removal, but besure to lubricate the O-rings with refrigerantoil before connecting the fittings.


16.4 All models have the receiver-drierlocated behind the right headlight,

although the configuration of lines andswitches may vary

3

13.6 From under the vehicle, remove thebolt from the lower air conditioning

compressor mounting

1 High-pressure switch2 Refrigerant lines3 Low-pressure switch4 Electrical connector

13 Have the system evacuated, rechargedand leak-tested by the qualified engineer whodischarged it.

17 Evaporator matrix - removal and refitting 5

Warning: Due to the potentialdangers associated with thesystem, you are strongly advised

to have any work on the air conditioningsystem carried out by a BMW dealer or air

conditioning specialist. At the very least,DO NOT dismantle any part of the system(hoses, compressor, line fittings, etc.) untilafter the system has been discharged by aqualified engineer. Refer to the pre-cautions given at the start of Section 12.

Removal1 Have the air conditioning systemdischarged (see Warning above).2 Remove the trim panel on the sides of thecentre console (see Chapter 11)3 Disconnect the electrical lead and removethe evaporator sensor.

4 Remove the evaporator cover, exposing therefrigerant lines.5 Disconnect the refrigerant lines from theevaporator matrix.6 Remove the evaporator matrix from thecase.

Refitting7 Refitting is the reverse procedure of theremoval.8 Have the system evacuated, recharged andleak-tested by the qualified engineer whodischarged it.


4

Carburettor (Solex 2B4)Main jet

Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X120Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X90

Air correction jetStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Venturi diameterStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 mmStage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 mm

Idle/air jetStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50/120Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40/125

Float needle valve diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 mmChoke gap (pulldown) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 to 5.5 mmThrottle positioner spring preload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.0 to 24.0 mmFloat level

Stage 1 float chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.0 to 29.0 mmStage 2 float chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29.0 to 31.0 mm

Chapter 4 Fuel and exhaust systems

Accelerator cable - check, adjustment and renewal . . . . . . . . . . . . . 9Air cleaner assembly - removal and refitting . . . . . . . . . . . . . . . . . . . 8Air filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Airflow meter - check, removal and refitting . . . . . . . . . . . . . . . . . . . 16Carburettor - cleaning and adjustment . . . . . . . . . . . . . . . . . . . . . . . 12Carburettor - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Carburettor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 11Cold start injector and thermotime switch -

checkand renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Engine idle speed check and adjustment . . . . . . . . . See Chapter 1Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Exhaust system servicing - general information . . . . . . . . . . . . . . . . 22Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Fuel injection system - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Fuel injection system - depressurising . . . . . . . . . . . . . . . . . . . . . . . 2

Fuel injection system - fault finding . . . . . . . . . . . . See end of ChapterFuel injection - general information . . . . . . . . . . . . . . . . . . . . . . . . . . 13Fuel injection systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Fuel injectors - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . 20Fuel lines and fittings - repair and renewal . . . . . . . . . . . . . . . . . . . . 5Fuel pressure regulator - check and renewal . . . . . . . . . . . . . . . . . . 18Fuel pump, transfer pump and fuel level sender unit -

removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Fuel pump/fuel pressure - check . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Fuel system check . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Fuel tank - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Fuel tank cleaning and repair - general information . . . . . . . . . . . . . 7General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Idle air stabiliser valve - check, adjustment and renewal . . . . . . . . . 21Throttle body - check, removal and refitting . . . . . . . . . . . . . . . . . . . 17

4•1







Specifications

Contents

Carburettor (Solex 2BE)Main jet

Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X120Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X110

Air correction jetStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Venturi diameterStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 mmStage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 mm

Idle fuel jetStage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.5 mm

Idle air jetStage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Float needle valve diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 mmThrottle positioner coil resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.97 to 1.63 ohmsIntake air temperature resistance

-10º C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8200 to 10 500 ohms20º C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2200 to 2700 ohms80º C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 to 360 ohms

Float levelStage 1 float chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27.0 to 29.0 mmStage 2 float chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29.0 to 31.0 mm

Fuel pressure checks (carburettor engines)Fuel pump delivery pressure (engine idling) . . . . . . . . . . . . . . . . . . . . . . 0.1 to 0.3 bars

Fuel pressure checks (fuel injection engines)Fuel system pressure (relative to intake manifold pressure)

3-Series (E30)316i with M40/B16 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ± 0.06 bars318i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 to 3.0 bars318i with M40/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ± 0.06 bars320i with M20/B20 engine (L-Jetronic) . . . . . . . . . . . . . . . . . . . . . . 2.5 to 3.0 bars320i with M20/B20 engine (Motronic) . . . . . . . . . . . . . . . . . . . . . . . 2.5 ± 0.05 bars325i with M20/B25 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ± 0.05 bars

5-Series (E28/”old-shape”)All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 to 3.0 bars

5-Series (E34/”new-shape”)518i with M40/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ± 0.06 barsAll other models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 to 3.0 bars

Fuel system hold pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 barsFuel pump maximum pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 to 6.9 barsFuel pump hold pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 barsTransfer pump pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.28 to 0.35 bars

InjectorsInjector resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 to 17.5 ohms

Accelerator cable free play . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 mm

Torque wrench settings NmCarburettor mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Fuel pump to cylinder head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Throttle body nuts/bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 to 26

4•2 Fuel and exhaust systems


With the exception of early models (316 and518 models) all engines are equipped withelectronic fuel injection.

Early 316 and 518 models are equippedwith Solex carburettors. The carburettor fittedis either a Solex 2B4 (early models) or 2BE (later models). The mechanical fuel pump

is driven by an eccentric lobe on thecamshaft.

Fuel injection models are equipped witheither the L-Jetronic or the Motronic fuelinjection system. From 1988, fuel injectionmodels are equipped with an updated versionof the Motronic system - this system is easilydistinguished from the earlier system by theabsence of a cold start injector. The electricfuel pump is located beneath the rear of thevehicle, or inside the fuel tank. The fuel pumprelay on Motronic systems is activated from a

earth signal from the Motronic control unit(ECU). The fuel pump operates for a fewseconds when the ignition is first switched on,and it continues to operate only when theengine is actually running.

Air intake systemThe air intake system consists of the air

filter housing, the airflow meter and throttlebody (fuel injection models), and the intakemanifold. All components except the intakemanifold are covered in this Chapter; for

information on removing and refitting theintake manifold, refer to Chapter 2A.

The throttle valve inside the throttle body orcarburettor is actuated by the acceleratorcable. When you depress the acceleratorpedal, the throttle plate opens and airflowthrough the intake system increases.

On fuel injection systems, a flap inside theairflow meter opens wider as the airflowincreases. A throttle position switch attachedto the pivot shaft of the flap detects the angleof the flap (how much it’s open) and convertsthis to a voltage signal, which it sends to thecomputer.

Fuel systemOn carburettor models, the fuel pump

supplies fuel under pressure to thecarburettor. A needle valve in the floatchamber maintains the fuel at a constantlevel. A fuel return system channels excessfuel back to the fuel tank.

On fuel injection models, an electric fuelpump supplies fuel under constant pressureto the fuel rail, which distributes fuel to theinjectors. The electric fuel pump is locatedinside the fuel tank on later models, or besidethe fuel tank on early models. Early modelsalso have a transfer pump located in the fueltank. The transfer pump acts as an aid to thelarger main pump for delivering the necessarypressure. A fuel pressure regulator controlsthe pressure in the fuel system. The fuelsystem also has a fuel pulsation damperlocated near the fuel filter. The damperreduces the pressure pulsations caused byfuel pump operation, and the opening andclosing of the injectors. The amount of fuelinjected into the intake ports is preciselycontrolled by an Electronic Control Unit (ECUor computer). Some later 5-Series modelshave a fuel cooler in the return line.

Electronic control system (fuelinjection system)

Besides altering the injector openingduration as described above, the electroniccontrol unit performs a number of other tasksrelated to fuel and emissions control. Itaccomplishes these tasks by using datarelayed to it by a wide array of informationsensors located throughout the engine

compartment, comparing this information toits stored map, and altering engine operationby controlling a number of different actuators.Since special equipment is required, mostfault diagnosis and repair of the electroniccontrol system is beyond the scope of thehome mechanic. Additional information andtesting procedures for the emissions systemcomponents (oxygen sensor, coolanttemperature sensor, EVAP system, etc.) iscontained in Chapter 6.

2 Fuel injection system -depressurising 1


smoke or allow open flames or bare lightbulbs near the work area. Also, don’t workin a garage where a natural gas-typeappliance with a pilot light is present.1 Remove the fuel pump fuse from the mainfuse panel (see illustrations). Note: Consultyour owner’s handbook for the exact locationof the fuel pump fuse, if the information is notstamped onto the fusebox cover.2 Start the engine, and wait for it to stall.Switch off the ignition.3 Remove the fuel filler cap to relieve the fueltank pressure.4 The fuel system is now depressurised.Note: Place a rag around fuel lines beforedisconnecting, to prevent any residual fuelfrom spilling onto the engine (seeillustration).5 Disconnect the battery negative cablebefore working on any part of the system.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

3 Fuel pump/fuel pressure -check 3


smoke, or allow open flames or bare lightbulbs, near the work area. Also, don’t workin a garage where a natural gas-typeappliance with a pilot light is present.

Carburettor engines1 To test the fuel pump, it will be necessary toconnect a suitable pressure gauge betweenthe fuel pump outlet, and the carburettorsupply pipe. For this particular test, the fuelreturn valve, which is normally connected inthe fuel line from the fuel pump to thecarburettor, must be bypassed.2 With the engine running at idle speed, thepump pressure should be between 0.1 and0.3 bars.3 Should a pressure gauge not be available, asimpler (but less accurate) method of testingthe fuel pump is as follows.4 Disconnect the outlet hose from the fuelpump.5 Disconnect the LT lead from the coil, toprevent the engine firing, then turn the engineover on the starter. Well-defined spurts of fuelshould be ejected from the outlet hose.

Fuel injection enginesNote 1: The electric fuel pump is locatedinside the fuel tank on later models, or besidethe fuel tank on early models. Early models arealso equipped with a transfer pump located inthe fuel tank. The transfer pump feeds themain pump, but can’t generate the highpressure required by the system.Note 2: The fuel pump relay on Motronicsystems is activated by an earth signal fromthe Motronic control unit (ECU). The fuelpump operates for a few seconds when theignition is first switched on, and thencontinues to operate only when the engine isactually running.

Fuel and exhaust systems 4•3

2.4 Be sure to place a rag under andaround any fuel line when disconnecting

2.1b Removing the fuel pump fuse on 5-Series models

2.1a Removing the fuel pump fuse on 3-Series models

4

Note 3: The following checks assume the fuelfilter is in good condition. If you doubt thecondition of your fuel filter, renew it (seeChapter 1).Note 4: In order to get accurate test results, itis recommended that the fuel pressure bechecked from both the main fuel pump andtransfer pump where applicable.

Fuel pump/transfer pump operationalcheck6 Bridge the connector terminals thatcorrespond to the fuel pump relay pins 30 and87b (L-Jetronic systems) or 30 and 87(Motronic systems) with a suitable jumper wire(see illustrations).7 Have an assistant switch the ignition onwhile you listen at the fuel tank. You shouldhear a whirring sound for a couple of seconds.Note: This test applies to the transfer pumpalso. If there is no whirring sound, there is aproblem in the fuel pump circuit. Check thefuel pump main fuse and relay first (seeChapter 12). If the main relay is OK, test thefuel pump relay.

Fuel system pressure check8 Depressurise the fuel system (see Section 2).9 Detach the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.10 Detach the fuel feed line from the fuel railon L-Jetronic (see illustration) and earlyMotronic systems, or from the fuel filter to themain fuel line on later Motronic systems.11 Using a tee-piece (three-way fitting), ashort section of high-pressure fuel hose andclamps, attach a fuel pressure gauge withoutdisturbing normal fuel flow (see illustration).

Warning: Do not use a plastic teefitting for this test. It won’t beable to withstand the fuel systempressure.

12 Reconnect the battery.13 Bridge the terminals of the fuel pumprelay using a jumper wire.14 Turn the ignition switch on.15 Note the fuel pressure, and compare itwith the pressure listed in this Chapter’sSpecifications.16 If the system fuel pressure is less thanspecified:a) Check the system for fuel leaks. Repair

any leaks found, and recheck the fuelpressure.

b) If there are no leaks, fit a new fuel filterand recheck the fuel pressure.

c) If the pressure is still low, check the fuelpump pressure (see below) and the fuelpressure regulator (see Section 18).

17 If the pressure is higher than specified,check the fuel return line for an obstruction. Ifthe line is not obstructed, renew the fuelpressure regulator.18 Turn the ignition off, wait five minutes andlook at the gauge. Compare the reading withthe system hold pressure listed in thisChapter’s Specifications. If the hold pressureis less than specified:a) Check the system for fuel leaks. Repair

any leaks found, and recheck the fuelpressure.

b) Check the fuel pump pressure (seebelow).

c) Check the fuel pressure regulator (seeSection 18).

d) Check the injectors (see Section 20).

Fuel pump pressure checkWarning: For this test, a fuelpressure gauge with a bleedvalve will be needed, in order torelieve the high fuel pressure

safely. After the test is completed, thenormal procedure for depressurising willnot work, because the gauge is connecteddirectly to the fuel pump.


3.10 Disconnect the fuel feed line(arrowed) from the fuel rail (L-Jetronic

system shown) . . .

3.6d . . . then, use a jumper wire to bridgethe terminals on the connector that

correspond to fuel pump relay pins 30 and87

3.6c On all 1989 and later models, removethe four bolts and the protective cover togain access to the fuel pump relay and

ECU . . .

3.6b On Motronic systems, use a jumperwire to bridge the terminals on the

connector that correspond to the fuelpump relay pins 30 and 87

3.6a On L-Jetronic systems, use a jumperwire to bridge the terminals on the

connector that correspond to the fuelpump relay pins 30 and 87b

3.11 . . . and connect the gauge betweenthe fuel feed line and the fuel rail using a

tee-piece fitting

19 Depressurise the fuel system (see Sec-tion 2).20 Detach the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.21 Detach the fuel feed hose from the fuelrail, and attach a fuel pressure gauge directlyto the hose. Note: If the tee fitting is stillconnected to the gauge, be sure to plug theopen end.22 Reconnect the battery.23 Using a jumper wire, bridge the terminalsof the fuel pump relay.24 Turn the ignition switch on to operate thefuel pump.25 Note the pressure reading on the gauge,and compare the reading to the fuel pumppressure listed in this Chapter’s Specifica-tions.26 If the indicated pressure is less thanspecified, inspect the fuel line for leaksbetween the pump and gauge. If no leaks arefound, renew the fuel pump.27 Turn the ignition off and wait five minutes.Note the reading on the gauge, and compareit to the fuel pump hold pressure listed in thisChapter’s Specifications. If the hold pressureis less than specified, check the fuel linesbetween the pump and gauge for leaks. If noleaks are found, renew the fuel pump.28 Remove the jumper wire. Relieve the fuelpressure by opening the bleed valve on thegauge and directing the fuel into a suitablecontainer. Remove the gauge and reconnectthe fuel line.

Transfer pump pressure check29 Depressurise the fuel system (see Sec-tion 2).30 Detach the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.31 Remove the transfer pump access plate(on some models, it’s located under the rearseat cushion - on others, it’s located underthe carpet in the luggage compartment).Disconnect the output hose from the transferpump, and connect a fuel pressure gauge tothe outlet pipe.32 Reconnect the battery.

33 Using a jumper wire, bridge the terminalsof the fuel pump relay.34 Turn the ignition switch on to operate thefuel pump.35 Note the pressure reading on the gauge,and compare to the value listed in thisChapter’s Specifications.36 If the indicated pressure is less thanspecified, renew the transfer pump.

Fuel pump relay check37 Switch on the ignition.38 Using a voltmeter, probe the followingterminals from the back of the relay electricalconnector. Check for battery voltage atterminal 30 (M20 and M30 engines) orterminal 15 (M10 and M40 engines). Note: Ifthere is no voltage on models with luggagecompartment-mounted batteries, check for afaulty fusible link. The 50-amp link is about 6 inches from the battery, in a black wire.39 Turn the ignition off, and disconnect therelay from the electrical connector. Using avoltmeter, probe the connector terminals thatcorrespond to fuel pump relay pins 85 (-) and86(+) on M20 and M30 engines, or terminal 50and earth on M10 and M40 engines. Have anassistant turn the engine over on the starter,and observe the voltage reading. Batteryvoltage should be indicated.40 If there is no voltage, check the fuse(s)and the wiring circuit for the fuel pump relay. Ifthe voltage readings are correct, and the fuelpump only runs with the jumper wire in place,then renew the relay.41 If the fuel pump still does not run, checkfor the proper voltage at the fuel pumpterminals (see Section 4). If necessary, renewthe fuel pump.

4 Fuel pump, transfer pumpand fuel level sender unit -removal and refitting

2Warning: Fuel is extremelyflammable, so take extraprecautions when you work onany part of the fuel system. Don’t

smoke, or allow open flames or bare lightbulbs, near the work area. Also, don’t workin a garage where a natural gas-typeappliance with a pilot light is present.

Fuel pump (carburettor engines)1 Disconnect the battery negative cable.Disconnect both hoses from the pump, andunscrew and remove the two securing nuts(see illustration).2 Carefully withdraw the pump from thecylinder head. If it’s stuck, a slight downwardtap on the thick insulating distance piece witha piece of wood, should free it.3 Remove the two thin gaskets.4 The fuel pump is a sealed unit, and it is notpossible to renew any of the internalcomponents. Should an internal fault occur, itmust be renewed complete.

5 Refitting is a reversal of the removalprocedure, but renew the thin gaskets eachside of the insulating distance piece, andtighten the fuel pump down evenly to thetorque stated in the Specifications. On noaccount alter the thickness of the distancepiece, or the correct operation of the fuelpump will be upset.

Fuel pump (fuel injectionengines)Note 1: The electric fuel pump is locatedinside the fuel tank on later models with theMotronic system, or adjacent to the fuel tankon the L-Jetronic system. The early modelsare also equipped with a transfer pumplocated in the fuel tank. The transfer pumpfeeds the larger main pump, which deliversthe high pressure required for proper fuelsystem operation.Note 2: The fuel level sender unit is located inthe fuel tank with the transfer pump on earlymodels, or with the main fuel pump on latermodels.6 Depressurise the fuel system (see Sec-tion 2) and remove the fuel tank filler cap torelieve pressure in the tank.7 Disconnect the battery negative cable.



Externally-mounted fuel pump8 Raise and support the vehicle.9 Remove the two rubber boots that protectthe fuel pump connectors, and disconnect thewires from the pump (see illustration).10 Using hose clamps, pinch shut the fuelhoses on each side of the fuel pump. If youdon’t have any hose clamps, wrap the hoseswith rags, and clamp them shut with self-locking pliers, tightened just enough toprevent fuel from flowing out.11 Disconnect the hoses from the pump.12 Remove the fuel pump mounting screws


4.1 Fuel pump on carburettor engines

4

and clamps, and remove the fuel pump fromthe under the vehicle.13 Refitting is the reverse of removal.

In-tank fuel pump or transfer pump14 On some models, access to the fuel pumpis gained by removing the rear seat cushion.On other models, access is gained byremoving the carpet from the luggagecompartment.15 Remove the screws from the fuel pumpaccess cover (see illustration).16 Remove the cover.17 Locate the fuel pump and sender unitelectrical connectors (see illustrations) and

unplug them. Also, disconnect the fuel inletand return lines.18 On some models, the assembly must berotated anti-clockwise to disengage thelocking lugs from the fuel tank (seeillustration). On other models, the assemblyis secured to the tank with nuts (seeillustration). Carefully lift the assembly fromthe fuel tank (see illustrations). It may benecessary to twist the assembly slightly, toget the float to clear the opening.19 On early models, remove the transferpump mounting screws and clamps, andseparate the transfer pump from theassembly.20 Refitting is the reverse of removal. If thegasket between the fuel pump and fuel tank isdried, cracked or damaged, renew it.

Fuel level sender unit - checkand renewal21 Remove the main fuel pump or transferpump (as described previously) along with thefuel level sender unit.22 Connect an ohmmeter across thedesignated terminals, and check for the


4.18e Exploded view of the fuel pumpassembly on later Motronic systems

4.18d . . . then pull the fuel pump straightup and out of the turret at the bottom of

the fuel tank (keep all the fuel lines intact)4.18c On later Motronic systems, firstremove the fuel level sender unit . . .

4.18b On models with mounting nuts,remove the nuts (arrowed) to release the

assembly from the fuel tank

4.18a On models with locking lugs, usetwo screwdrivers to rotate the assembly

out of the notches

4.17b To unplug the connector, prise thebracket until the notch aligns with the slot

on the retaining clip, and release theconnector from the assembly

4.17a Transfer pump (1) and fuel levelsender unit (2) electrical connectors on an

early Motronic system

4.15 Remove the fuel pump cover screws(arrowed) and lift the cover off the floor of

the vehicle (on some models, the fuelpump cover is located under the rear seat

- on other models it’s located in theluggage compartment)

4.9 Lift up the rubber boots (arrowed) anddetach the electrical connectors from the

fuel pump

correct resistance. On L-Jetronic and earlyMotronic systems, follow the table below. Onlater Motronic systems, connect theohmmeter probes onto the fuel level senderunit terminals that correspond to pins 1 and 3on the electrical connector (see illustrations).The resistance should decrease as theplunger rises.L-Jetronic and early Motronic systemsTerminals Float position ResistanceG and 31 Slowly moving Resistance

fromthe EMPTY slowlyposition to the decreasesFULL positionEMPTY 71.7 ± 2.3 ohmsFULL 3.2 ± 0.7 ohms

W and 31 EMPTY (low Continuityfuel warning)

23 If the resistance readings are incorrect,renew the sender unit.24 Refitting is the reverse of removal.

5 Fuel lines and fittings - repair and renewal 3


smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you performany kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.1 Always disconnect the battery negativecable, and (on fuel injection models)depressurise the fuel system as described inSection 2, before servicing fuel lines orfittings.2 The fuel feed, return and vapour linesextend from the fuel tank to the enginecompartment. The lines are secured to theunderbody with clip and screw assemblies.

These lines must be occasionally inspectedfor leaks, kinks and dents (see illustration).3 If evidence of dirt is found in the system orfuel filter during dismantling, the lines shouldbe disconnected and blown out. On fuelinjection models, check the fuel strainer onthe in-tank fuel pump for damage anddeterioration.4 Because fuel lines used on fuel injectionvehicles are under high pressure, they requirespecial consideration. If renewal of a rigid fuelline or emission line is called for, use weldedsteel tubing meeting BMW specification or itsequivalent. Don’t use plastic, copper oraluminium tubing to renew steel tubing. Thesematerials cannot withstand normal vehiclevibration.5 When renewing fuel hoses, be sure to useonly hoses of original-equipment standard.

6 Fuel tank - removal and refitting 3


smoke, or allow open flames or bare lightbulbs, near the work area. Also, don’t workin a garage where a natural gas-typeappliance with a pilot light is present.When you perform any kind of work on thefuel system, wear safety glasses, and havea fire extinguisher on hand. If you spill anyfuel on your skin, clean it off immediatelywith soap and water.

Note: To avoid draining large amounts of fuel,make sure the fuel tank is nearly empty (ifpossible) before beginning this procedure.

1 Remove the fuel tank filler cap to relievefuel tank pressure.

2 On fuel injection models, depressurise thefuel system (see Section 2).3 Detach the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.4 Remove the tank drain plug (seeillustration) and drain the fuel into anapproved fuel container. If no drain plug isfitted, it should be possible to syphon the fuelout (not by mouth), otherwise the fuel will haveto be drained during the removal operation.5 Unplug the fuel pump/sender unit electricalconnector (as applicable) and detach the fuelfeed, return and vapour hoses (see Section 4).Where applicable, remove the rear seatcushion for access.6 Remove the fuel tank shield (seeillustration).7 Detach the fuel filler neck and breatherhoses.8 Raise and support the vehicle. On somemodels, it will also be necessary to removethe exhaust system and propeller shaft.9 Support the tank with a trolley jack.


4.22b Fuel level sender unit terminaldesignations on later Motronic systems -check the sender unit resistance across

terminals 1 and 3 of the connector

1 Fuel level sender unit earth2 Warning light3 Sender unit4 Fuel pump earth5 Fuel pump

4.22a Fuel level sender unit terminaldesignations on L-Jetronic and early

Motronic systems

6.4 Remove the tank drain plug (arrowed)and drain the fuel into a suitable container

5.2 When checking the fuel lines, don’toverlook these short sections of fuel hose

attached to the main fuel rail - they’re acommon source of fuel leaks

4

Position a block of wood between the jackhead and the fuel tank to protect the tank.10 Remove the mounting bolts at the cornersof the fuel tank, and unbolt the retainingstraps (see illustrations). Pivot the strapsdown until they’re hanging out of the way.

11 Lower the tank just enough so you cansee the top, and make sure you havedetached everything. Finish lowering the tank,and remove it from the vehicle.12 Refitting is the reverse of removal.

7 Fuel tank cleaning and repair- general information

1 All repairs to the fuel tank or filler neckshould be carried out by a professional whohas experience in this critical and potentiallydangerous work. Even after cleaning andflushing of the fuel system, explosive fumescan remain and ignite during repair of thetank.2 If the fuel tank is removed from the vehicle,it should not be placed in an area wheresparks or open flames could ignite the fumescoming out of the tank. Be especially carefulinside garages where a natural gas-typeappliance is located, because the pilot lightcould cause an explosion.

8 Air cleaner assembly -removal and refitting 1

1 Detach the battery negative cable.Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code


Carburettor engines2 Release the spring clips, then unscrew thecentre nut and lift off the cover (seeillustrations).3 Remove the air filter element, and wipeclean the air cleaner body and cover (seeillustration).4 To remove the body, first disconnect theinlet duct and warm-air hose (seeillustration).5 Disconnect the vacuum line at thecarburettor.


8.3 Remove the air cleaner element, andwipe clean the body and cover

8.2b . . . then remove the air cleaner covercentre nut, and lift off the cover

8.2a Release the air cleaner cover springclips . . .

6.10a Remove the fuel tank mountingbolts (one arrowed)

6.10b Remove the retaining strap bolts(one arrowed) and lower the fuel tank

6.6 Exploded view of the fuel tank assembly on later 5-Series models

6 Unscrew the four nuts retaining the aircleaner to the carburettor, and remove themetal ring (see illustrations).7 Unscrew the nut from the mounting bracket(see illustration).8 Lift the air cleaner from the carburettor, anddisconnect the crankcase ventilation hose(see illustration). If necessary, prise thesealing ring from the bottom of the air cleaner.9 Refitting is a reversal of removal, but alignthe arrow on the cover with the arrow on theinlet tube (see illustration).

Fuel injection engines10 Detach the air intake duct from the frontside of the air cleaner.

11 Detach the duct between the air cleanerand the throttle body.12 Remove the air filter (see Chapter 1).13 Unplug the electrical connector from theairflow meter (see Section 12).14 Remove the air cleaner mounting bolts(see illustration) and lift the air cleanerassembly from the engine compartment.15 Refitting is the reverse of removal. Ensurethat all ducts are securely refitted, or air leakswill result.

9 Accelerator cable - check,adjustment and renewal 1

Check1 Separate the air intake duct from thethrottle body (fuel injection models) or removethe air cleaner (carburettor models).2 Have an assistant depress the acceleratorpedal to the floor while you watch the throttlevalve. It should move to the fully-openposition.3 Release the accelerator pedal, and makesure the throttle valve returns smoothly to thefully-closed position. The throttle valve shouldnot contact the body at any time during itsmovement; if it does, the unit must be renewed.

Adjustment4 Warm the engine to normal operatingtemperature, then switch it off. Depress the

accelerator pedal to the floor twice, thencheck the cable free play at thecarburettor/throttle body. Compare it to thevalue listed in this Chapter’s Specifications.5 If the free play isn’t as specified, adjust it byturning the adjustment nut (see illustration).6 Have an assistant help you verify thethrottle valve is fully open when theaccelerator pedal is depressed to the floor.

RenewalNote: The following paragraphs describe theprocedure for fuel injection engines - theprocedure is similar on carburettor engines7 Disconnect the battery negative cable.


8.6b . . . and remove the metal ring8.6a Unscrew the four air cleaner-to-carburettor nuts . . .

8.4 Air cleaner inlet duct (1) and warm-airhose (2)

9.5 To adjust the accelerator cable freeplay, hold nut B stationary and turn nut A

(fuel injection engine shown)

8.14 Remove the two nuts (arrowed) fromthe air cleaner assembly (Motronic system

shown), and lift it off its mountings

8.8 Disconnecting the crankcaseventilation hose from the air cleaner

8.7 Air cleaner mounting bracket nut(arrowed)

8.9 Align the air cleaner cover arrowswhen refitting

4

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you

have the correct activation code beforedisconnecting the battery. Refer to theinformation on page 0-7 at the front of thismanual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.8 Loosen the cable adjuster locknuts, anddetach the cable from its support bracketlocated on the intake manifold (seeillustration).9 Pinch the plastic retainer with a pair ofneedle-nose pliers, and push it out of thebracket (see illustration).

10 Pull the cable down through the slot andaway from the bracket (see illustrations).11 Working from underneath the driver’s sideof the facia, reach up and detach theaccelerator cable from the top of the pedal.12 Pull the cable through the bulkhead, fromthe engine compartment side.13 Refitting is the reverse of removal. Adjustthe cable as described earlier.

10 Carburettor - general information

1 Early models are fitted with a Solex 2B4carburettor, and later models are fitted with aSolex 2BE carburettor. Both carburettors areof downdraught, two-stage type. The firststage is operated mechanically by theaccelerator pedal, and the second stage byvacuum control.2 Each stage has its own float chamber, floatassembly and needle valve, designed toreduce the effects of braking and centrifugalforces.3 On the 2B4 version, the primary stagechoke valve is operated by an automaticchoke (a bi-metal spring which is electricallyheated) during the warm-up period. Warm-upenrichment is also provided by a coolant-operated thermal valve and air temperature-controlled flow valve.4 On the 2BE version, an electronic control

unit is used to automatically adjust thecarburettor settings during warm-up andnormal temperature operation. The controlunit is located beneath the right-hand side ofthe facia.

11 Carburettor - removal and refitting 2

Removal1 Remove the air cleaner as described inSection 8.2 Disconnect the accelerator cable from thecarburettor with reference to Section 9.3 On automatic transmission models,disconnect the kickdown cable.4 Disconnect the wiring from the carburettor,noting the location of each wire.5 Remove the screw, and disconnect theearth cable from the throttle positionerbracket (see illustration).6 Disconnect the vacuum hoses, noting thatthe hose with the white tracer is located onthe white plastic ‘T’ piece, and the distributorvacuum hoses are located on the side of thecarburettor (see illustration).7 On the 2B4 carburettor, disconnect andplug the coolant hoses from the TM (thermalstarter) valve.8 Disconnect the fuel supply hose (seeillustration).


11.8 Disconnect the fuel supply hose(arrowed)

11.6 Note the locations of the carburettorvacuum hoses (arrowed) before

disconnecting them11.5 Remove the screw, and disconnect

the carburettor earth cable (arrowed)

9.10b After the cable is off the throttlevalve assembly, remove the plastic

retainer from the cable

9.10a Rotate the throttle valve and removethe cable end from the slotted portion of

the valve

9.9 Pinch the plastic retainer, and push itthrough the bracket recess on the throttle

valve

9.8 Push the rubber grommet from therear, and separate the cable from the

bracket

9 Unscrew the four bolts, and lift thecarburettor from the insulating flange on theintake manifold (see illustration).10 If necessary, unscrew the nuts andremove the insulating flange from the intakemanifold (see illustration).

Refitting11 Refitting is a reversal of removal, butclean the mating faces thoroughly. Theinsulating flange may be re-used, if it’s ingood condition. Adjust the accelerator cablewith reference to Section 9, and the kickdowncable (where applicable) with reference toChapter 7B.

12 Carburettor - cleaning and adjustment 4

Note: This Section describes the procedurefor the 2B4 carburettor. The procedure for the2BE carburettor is similar.

Cleaning1 Obtain a complete set of gaskets and sealsfor the carburettor.2 Wash clean the exterior surfaces of thecarburettor.

3 Using a screwdriver, prise the acceleratorpump linkage from the primary throttle arm(see illustration).4 Unscrew the bolts securing the cover to themain body. An Allen key is necessary toremove the centre bolt (see illustration).5 Prise the link from the choke valve plasticlever (see illustration).6 Lift the cover from the main body, andremove the gasket (see illustrations).7 Remove the screw securing the throttlepositioner bracket to the throttle housing (seeillustration).8 Disconnect the vacuum unit pullrod fromthe secondary throttle lever (see illustration).


12.3 Using a screwdriver to disconnectthe accelerator pump linkage (arrowed)

11.10 Carburettor insulating flange on theintake manifold can be removed if

necessary

11.9 Unscrew the four bolts (arrowed) andlift the carburettor from the intake

manifold

12.7 Throttle positioner bracket-to-throttlehousing screw (arrowed)

12.6c View of the carburettor main bodywith the cover removed

12.6b View of the underside of the cover

12.6a Lifting the cover from thecarburettor main body

12.5 Prise the link (arrowed) from thechoke valve plastic lever

12.4 Using an Allen key to remove thecarburettor cover centre bolt

4

12.13e The jet positions in the cover(arrowed)


12.13d Secondary bypass air jet (1), TM airjet (2), and air correction jet (3)

12.13c Secondary main jet (left) and TMfuel jet (right) tightened in the cover

12.13b Secondary main jet (1) and TM(thermal starter) fuel jet (2)

12.13a Unscrew the bypass jet from thesecondary float chamber

12.12b . . . then lift out the needle valves,keeping all components identified side for

side

12.12a Tap out the float pivot pins, andremove the floats . . .

12.11a Throttle housing removed from thecarburettor

12.11b Underside of the main body withthrottle housing removed - note gasket

12.10 Primary throttle lever securing nut -if removed, take care not to disturb the

return spring

12.9 Throttle housing-to-main bodysecuring screws (arrowed)

12.8 Disconnecting the vacuum unitpullrod

9 Remove the screws securing the throttlehousing to the main body (see illustration).10 Prise out the intermediate throttle link. Ifthis proves difficult, unscrew the nut anddisconnect the lever from the primary throttlespindle, taking care not to disturb the returnspring (see illustration).11 Separate the throttle housing from themain body, and remove the gasket (seeillustrations).12 With the cover inverted, tap out the floatpivot pins, remove the floats, and lift out thetwo needle valves - keeping all thecomponents identified side for side (seeillustrations).13 Unscrew the bypass fuel jet from thesecondary float chamber, then similarlyremove the jets from the cover - keeping themall identified for location (see illustrations).14 Clean all the components, and blow allthe internal channels clear using low airpressure.15 Reassembly is a reversal of dismantling,but note the following points:a) Fit the new gaskets and seals supplied in

the repair kit.b) Before refitting the cover, check that the

choke linkage arm is correctly located inthe lever (see illustration).

c) Check and if necessary adjust the floatsettings. Invert the cover, and check the

distance from the contact face (withoutgasket) to the top of the float, making surethat the needle valve spring-tensionedball is not depressed (see illustration).Note that the dimension is different forthe primary and secondary floats (seeSpecifications). If adjustment isnecessary, bend the float arm as required.

d) Make sure that the seal is fitted to the topof the accelerator pump (seeillustration).

AdjustmentNote: Idle speed and mixture adjustments arecovered in Chapter 1.

Automatic choke (2B4)16 Check that the automatic choke coverand housing alignment marks are clearlyvisible; if not, make new marks.17 Remove the three screws and withdrawthe metal ring (see illustration).18 Remove the plastic cover, at the sametime disengaging the bi-metal spring from thecontrol lever (see illustration).19 Fit a rubber band to the bottom of thecontrol lever. Push the pulldown lever to theright and use a 4.2 mm diameter drill to checkthe distance between the lower edge of thechoke valve and the wall of the carburettor

(see illustration). Alternatively apply vacuumto the pulldown unit to move the lever.20 If adjustment is necessary, turn the screwon the end of the pulldown unit (seeillustration).21 Refit the cover in reverse order, makingsure that the alignment marks are in line.

Throttle positioner (2B4)22 With the throttle in the idle position, checkthat the length of the spring on the throttlepositioner is 23.0 ± 1.0 mm. If not, adjust thenut as required.23 With no vacuum applied (engine stopped)check that the control travel, measuredbetween the stop screw and lever, is 5.0 ±0.5 mm. If necessary, loosen the locknut andturn the diaphragm rod as required. Tightenthe locknut on completion.


12.15b To check the float level, measurethe distance between the contact face and

the top of the float

12.15a Choke linkage arm located in theautomatic choke lever

12.20 If adjustment is necessary, turn thescrew (arrowed) on the end of the

pulldown unit

12.19 Fit a rubber band (2) to the bottomof the control lever, then push the

pulldown lever to the right, and use a 4.2 mm diameter drill (1) to check the

distance between the lower edge of thechoke valve and the wall of the carburettor

12.17 Remove the three screws andwithdraw the metal ring

12.15c Accelerator pump seal (arrowed)

12.18 Remove the automatic choke cover,at the same time disengaging the bi-metal

spring from the control lever

4

Throttle positioner (2BE)24 Special tools are required to carry out acomprehensive adjustment on the 2BEcarburettor. This work should therefore be leftto a BMW dealer.

13 Fuel injection - general information

The fuel injection system is composed ofthree basic sub-systems: fuel system, airintake system and electronic control system.

Fuel systemAn electric fuel pump, located inside the

fuel tank or beside the fuel tank, supplies fuelunder constant pressure to the fuel rail, whichdistributes fuel evenly to all injectors. Fromthe fuel rail, fuel is injected into the intakeports, just above the intake valves, by the fuelinjectors. The amount of fuel supplied by theinjectors is precisely controlled by anElectronic Control Unit (ECU). An additionalinjector, known as the cold start injector (L-Jetronic and early Motronic systems only),supplies extra fuel into the intake manifold forstarting. A pressure regulator controls systempressure in relation to intake manifoldvacuum. A fuel filter between the fuel pumpand the fuel rail filters the fuel, to protect thecomponents of the system.

Air intake systemThe air intake system consists of an air filter

housing, an airflow meter, a throttle body, theintake manifold, and the associated ducting.The airflow meter is an information-gatheringdevice for the ECU. These models areequipped with the vane-type airflow meter. Apotentiometer measures intake airflow, and atemperature sensor measures intake airtemperature. This information helps the ECUdetermine the amount of fuel to be injected bythe injectors (injection duration). The throttleplate inside the throttle body is controlled bythe driver. As the throttle plate opens, theamount of air that can pass through thesystem increases, so the potentiometer opensfurther and the ECU signals the injectors toincrease the amount of fuel delivered to theintake ports.

Electronic control systemThe computer control system controls the

fuel system and other systems by means ofan Electronic Control Unit (ECU). The ECUreceives signals from a number of informationsensors which monitor such variables asintake air volume, intake air temperature,coolant temperature, engine rpm,acceleration/deceleration, and exhaustoxygen content. These signals help the ECUdetermine the injection duration necessary forthe optimum air/fuel ratio. These sensors andtheir corresponding ECU-controlled output

actuators are located throughout the enginecompartment. For further informationregarding the ECU and its relationship to theengine electrical systems and ignition system,refer to Chapters 5 and 6.

Either an L-Jetronic system or a Motronicsystem is fitted. Later models have anupdated version of the original Motronicsystem.

14 Fuel injection systems

L-Jetronic fuel injection systemThe Bosch L-Jetronic fuel injection system

is used on most 3-Series models up to 1987,and on most E28 (“old-shape”) 5-Seriesmodels. It is an electronically-controlled fuelinjection system that utilises one solenoid-operated fuel injector per cylinder. The systemis governed by an Electronic Control Unit(ECU) which processes information sent byvarious sensors, and in turn precisely meters the fuel to the cylinders by adjusting the amount of time that the injectorsare open.

An electric fuel pump delivers fuel underhigh pressure to the injectors, through the fuelfeed line and an in-line filter. A pressureregulator keeps fuel available at an optimumpressure, allowing pressure to rise or falldepending on engine speed and load. Anyexcess fuel is returned to the fuel tank by aseparate line.

A sensor in the air intake duct constantlymeasures the mass of the incoming air, andthe ECU adjusts the fuel mixture to provide anoptimum air/fuel ratio.

Other components incorporated in thesystem are the throttle valve (which controlsairflow to the engine), the coolant temperaturesensor, the throttle position switch, idlestabiliser valve (which bypasses air aroundthe throttle plate to control idle speed) andassociated relays and fuses.

Motronic fuel injection systemThe Motronic system combines the fuel

control of the L-Jetronic fuel injection systemwith the control of ignition timing, idle speedand emissions into one control unit.

The fuel injection and idle speed controlfunctions are similar to those used on the L-Jetronic system described above. For moreinformation on the Motronic system, seeChapter 6.

An oxygen sensor is mounted in theexhaust system on later models with acatalytic converter. This sensor continuallyreads the oxygen content of the exhaust gas.The information is used by the ECU to adjustthe duration of injection, making it possible toadjust the fuel mixture for optimum converterefficiency and minimum emissions.

15 Fuel injection system - check 2


smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you performany kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.1 Check the earth wire connections. Checkall wiring harness connectors that are relatedto the system. Loose connectors and poorearths can cause many problems thatresemble more serious malfunctions.2 Make sure the battery is fully charged, asthe control unit and sensors depend on anaccurate supply voltage in order to properlymeter the fuel.3 Check the air filter element - a dirty orpartially-blocked filter will severely impedeperformance and economy (see Chapter 1).4 If a blown fuse is found, renew it and see ifit blows again. If it does, search for an earthedwire in the harness related to the system.5 Check the air intake duct from the airflowmeter to the intake manifold for leaks. Intakeair leaks can cause a variety of problems. Alsocheck the condition of the vacuum hosesconnected to the intake manifold.6 Remove the air intake duct from the throttlebody, and check for dirt, carbon and otherresidue build-up. If it’s dirty, clean it withcarburettor cleaner and a toothbrush.7 With the engine running, place ascrewdriver or a stethoscope against eachinjector, one at a time, and listen for a clickingsound, indicating operation (see illustration).


15.7 Use a stethoscope or screwdriver todetermine if the injectors are workingproperly - they should make a steady

clicking sound that rises and falls withengine speed changes

8 Check the fuel system pressure (seeSection 3).9 If these checks do not locate the problem,take the vehicle to a BMW dealer, who will beable to read the fault codes stored in the ECU,using special equipment.

16 Airflow meter - check,removal and refitting 2

Check (L-Jetronic systems)1 Remove the duct from the intake end of theairflow meter. Carefully open and close thesensor flap (see illustration), and check forbinding. The flap can bend during a backfire,and cause incorrect resistance readings. Theflap will bind and stick in a partially-openposition, causing the engine to run rich, andstall when it returns to idle. 2 Disconnect the electrical connector fromthe airflow meter.3 Using an ohmmeter, check the resistance

between terminals 7 and 8 (see illustration).The resistance should increase steadily(without any “flat spots”) as the sensor flap isslowly moved from the fully-closed position tothe fully-open position.4 Also, check the intake air temperaturesensor (inside the airflow meter). Using anohmmeter, probe terminals 8 and 9 (seeillustration 16.3) and check for the properresistance. The resistance should be 2200 to2700 ohms at 20º C.5 If the resistance readings are correct, checkthe wiring harness (see Chapter 12). Plug inthe connector to the airflow meter. Ensurethat the ignition is switched off. Disconnectthe electrical connector from the ECU (locatedunder the right-hand side of the facia) andprobe terminals 7 and 8 (see illustration) withan ohmmeter. Carefully move the door of theairflow meter, and observe the change inresistance as it moves from closed to fully-open. The test results should be the same asparagraph 3. If there are any differences in thetest results, there may be a shorted-out orbroken wire in the harness.

Check (Motronic systems)6 Ensure that the ignition is switched off.

Remove the ECU access cover (see Chap-ter 6) and disconnect the harness connector(see illustration).7 Using an ohmmeter, probe the designatedterminals of the ECU electrical connector (seeillustrations) and check for the properchange in resistance while moving the sensorflap. On early Motronic systems, probeterminals 7 and 9. On later Motronic systems,probe terminals 7 and 12. The resistanceshould increase steadily (without any “flatspots”) as the sensor flap is slowly movedfrom the fully-closed position to the fully-openposition. Note: Early Motronic systems aredistinguishable by the 35-pin ECU electricalconnector; later Motronic systems use a 55-pin connector.8 If the resistance readings are incorrect,check the wiring harness.

Removal and refitting (allsystems)9 Disconnect the electrical connector fromthe airflow meter.10 Remove the air cleaner assembly (seeSection 8).11 Remove the nuts (see illustrations), andlift the airflow meter from the enginecompartment or from the air cleanerassembly.12 Refitting is the reverse of removal.


16.5 The ECU is located under the right-hand side of the facia. Unplug the

electrical connector, and check theresistance between terminals 7 and 8 as inparagraph 3. The test results should be the

same.

16.3 Connect an ohmmeter to terminals 7and 8 of the airflow meter, and check for asmooth change in resistance as the vanedoor of the airflow meter is slowly opened

and closed

16.1 Check for binding of the flap in theairflow meter as it nears closing positionor wide-open position. Any hesitation orbinding will cause erratic idle conditions,rich fuel mixture or poor acceleration andthrottle response (airflow meter removed

for clarity)

16.7b Unplug the connector, connect theohmmeter probes to terminals 7 and 9

(early Motronic systems) and check for asmooth change in resistance as the dooron the airflow meter is slowly opened and

closed

16.7a Connect the ohmmeter probes toterminals 7 and 12 (later Motronic systems)

of the ECU connector and check for asmooth change in resistance as the dooron the airflow meter is slowly opened and

closed

16.6 Remove the under-facia panel to gainaccess to the ECU on Motronic systems

(left-hand-drive model shown)

4

17 Throttle body - check,removal and refitting 2

Check1 Detach the air intake duct from the throttlebody (see Section 8) and move the duct out ofthe way.2 Have an assistant depress the throttlepedal while you watch the throttle valve.Check that the throttle valve moves smoothlywhen the throttle is moved from closed (idleposition) to fully-open (wide-open throttle).3 If the throttle valve is not working properly,renew the throttle body unit.

Warning: Wait until the engine iscompletely cool before beginningthis procedure.Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code



4 Detach the battery negative cable.

5 Detach the air intake duct from the throttlebody, and place to one side.6 Detach the accelerator cable from thethrottle body (see Section 9).7 Detach the cruise control cable, if applicable.8 Clearly label all electrical connectors(throttle position sensor, cold start injector,idle air stabiliser, etc), then unplug them.9 Clearly label all vacuum hoses, then detachthem.10 Unscrew the radiator or expansion tankcap to relieve any residual pressure in thecooling system, then refit it. Clamp shut thecoolant hoses, then loosen the hose clampsand detach the hoses. Be prepared for somecoolant leakage.

11 Remove the throttle body mounting nuts(upper) and bolts (lower), and detach thethrottle body from the air intake plenum (seeillustration).12 Cover the air intake plenum opening witha clean cloth, to prevent dust or dirt fromentering while the throttle body is removed.13 Refitting is the reverse of removal. Be sureto tighten the throttle body mounting nuts tothe torque listed in this Chapter’s Specifica-tions, and adjust the throttle cable (seeSection 9) on completion.

18 Fuel pressure regulator -check and renewal 3


smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you performany kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.



Check1 Depressurise the fuel system (see Sec-tion 2).2 Detach the battery negative cable.3 Disconnect the fuel line and connect a fuelpressure gauge (see Section 3). Reconnectthe battery.

4 Pressurise the fuel system (refit the fuelpump fuse and switch on the ignition), andcheck for leakage around the gaugeconnections.5 Connect a vacuum pump to the fuelpressure regulator (see illustration).6 Run the fuel pump (see Section 3). Read thefuel pressure gauge with vacuum applied tothe pressure regulator, and also with novacuum applied. The fuel pressure shoulddecrease as vacuum increases.7 Stop the fuel pump and reconnect thevacuum hose to the regulator. Start the engineand check the fuel system pressure at idle,comparing your reading with the value listedin this Chapter’s Specifications. Disconnectthe vacuum hose and watch the gauge - thepressure should jump up to maximum as soonas the hose is disconnected.8 If the fuel pressure is low, pinch the fuelreturn line shut and watch the gauge. If thepressure doesn’t rise, the fuel pump isdefective, or there is a restriction in the fuelfeed line. If the pressure now rises sharply,renew the pressure regulator.9 If the indicated fuel pressure is too high,stop the engine, disconnect the fuel return lineand blow through it to check for a blockage. Ifthere is no blockage, renew the fuel pressureregulator.10 If the pressure doesn’t fluctuate asdescribed in paragraph 7, connect a vacuum


18.5 Carefully watch the fuel pressuregauge as vacuum is applied (fuel pressure

should decrease as vacuum increases)

17.11 Remove the nuts (arrowed) and liftthe throttle body from the intake manifold(the two lower bolts are hidden from view)

16.11b Remove the nuts (arrowed) fromthe air cleaner housing, and detach the

airflow meter

16.11a Push the tab and remove the airduct from inside the air cleaner assembly

gauge to the pressure regulator vacuum hose,and check for vacuum (engine idling).11 If there is vacuum present, renew the fuelpressure regulator.12 If there isn’t any reading on the gauge,check the hose and its port for a leak or arestriction.

Renewal13 Depressurise the fuel system (see Sec-tion 2).14 Detach the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.15 Detach the vacuum hose and fuel returnhose from the pressure regulator, thenunscrew the mounting bolts (see illustration).16 Remove the pressure regulator.17 Refitting is the reverse of removal. Be sureto use a new O-ring. Coat the O-ring with alight film of engine oil prior to refitting.18 Check for fuel leaks after refitting thepressure regulator.

19 Cold start injector andthermotime switch - checkand renewal

2Warning: Fuel is extremelyflammable, so take extraprecautions when you work onany part of the fuel system. Don’t

smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you perform

any kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.

Check

Cold start injector1 The engine coolant should be below 30ºCfor this check. Preferably, the engine shouldhave been switched off for several hours.Disconnect the electrical connector from thecold start injector (see illustration) and moveit aside, away from the work area - there willbe fuel vapour present. Remove the twoscrews holding the injector to the air intakeplenum, and take the injector out. The fuel linemust be left connected. Wipe the injectornozzle. Disable the ignition system bydetaching the coil wire from the centreterminal of the distributor cap, and earthing iton the engine block with a jumper wire. Runthe fuel pump for 1 minute by bridging theappropriate relay terminals (see Section 3).There must be no fuel dripping from thenozzle. If there is, the injector is faulty andmust be renewed. Switch off the ignition andremake the original fuel pump relayconnections.2 Now direct the nozzle of the injector into acan or jar. Reconnect the electrical connectorto the injector. Have an assistant switch onthe ignition and operate the starter. Theinjector should squirt a conical-shaped spray

into the jar (see illustration). If the spraypattern is good, the injector is workingproperly. If the spray pattern is irregular, theinjector is fouled or damaged, and should becleaned or renewed.3 If the cold start injector does not spray anyfuel, check for a voltage signal at the electricalconnector for the cold start injector when thestarter motor is operated (see illustration). Ifthere is no voltage, check the thermotimeswitch.

Thermotime switch4 The thermotime switch detects thetemperature of the engine, and controls theaction of the cold start injector. It is usuallylocated up front, near the coolant temperaturesensor. The engine coolant should be below30ºC for this check. Preferably, the engineshould have been switched off for severalhours. Disable the ignition system by detachingthe coil wire from the centre terminal of thedistributor cap, and earthing it on the engineblock with a jumper wire. Pull back the rubberboot from the thermotime switch (seeillustration) and probe the black/yellow wireconnector terminal with a voltmeter.5 Have an assistant switch on the ignition andoperate the starter. The voltmeter shouldregister a voltage signal the moment thestarter engages. This signal should lastapproximately 6 to 10 seconds, depending onthe temperature of the engine.


19.2 Watch for a steady, conical-shapedspray of fuel when the starter motor is

operated

19.1 Cold start injector electricalconnector (arrowed) on the M10 engine.Most cold start injectors are mounted in

the intake manifold

18.15 Remove the two bolts (arrowed) andremove the fuel pressure regulator from

the fuel rail

19.4 Check for a voltage signal on theblack/yellow wire of the thermotime switch

when the ignition is on

19.3 Check for a voltage signal (about 12 volts) at the cold start injector connector

when the starter motor is operated

4

6 If the voltage is correct, unplug theelectrical connector and, using an ohmmeter,check for continuity between the terminals ofthe thermotime switch (see illustration).Continuity should exist.7 Reconnect the coil lead, start the engineand warm it up above 41ºC. When the engineis warm, there should be no continuitybetween the terminals. If there is, the switch isfaulty and must be renewed. Note: On 5-Series models, there are several types ofthermotime switch. Each one is stamped withan opening temperature and maximumduration.

Renewal

Cold start injector8 Depressurise the fuel system (see Sec-tion 2).9 Disconnect the electrical connector fromthe cold start injector.10 Where applicable, using a ring spanner ordeep socket, remove the fuel line fittingconnected to the cold start injector. On othermodels, simply loosen the hose clamp anddetach the hose from the injector.11 Remove the cold start injector securingbolts, and remove the injector.12 Refitting is the reverse of removal. Cleanthe mating surfaces, and use a new gasket.

Thermotime switchWarning: Wait until the engine iscompletely cool before beginningthis procedure. Also, remove thecap from the expansion tank or

radiator to relieve any residual pressure inthe cooling system.13 Prepare the new thermotime switch forfitting by applying a light coat of threadsealant to the threads.14 Disconnect the electrical connector fromthe old thermotime switch.15 Using a deep socket, or a ring spanner,unscrew the switch. Once the switch isremoved coolant will start to leak out, soinsert the new switch as quickly as possible.Tighten the switch securely, and plug in theelectrical connector.

20 Fuel injectors - check and renewal 2


smoke, or allow open flames or bare lightbulbs, near the work area. Don’t work in agarage where a natural gas-type appliance(such as a water heater or clothes dryer)with a pilot light is present. If you spill anyfuel on your skin, rinse it off immediatelywith soap and water. When you performany kind of work on the fuel system, wearsafety glasses, and have a fireextinguisher on hand.

Check

In-vehicle check1 Using a mechanic’s stethoscope (availableat most car accessory shops), check for aclicking sound at each of the injectors whilethe engine is idling (see illustration 15.7).

2 The injectors should make a steady clickingsound if they are operating properly.3 Increase the engine speed above 3500 rpm.The frequency of the clicking sound shouldrise with engine speed.4 If an injector isn’t functioning (not clicking),purchase a special injector test light (a caraccessory shop or fuel injection specialistmay be able to help) and connect it to theinjector electrical connector. Start the engineand make sure the light flashes. If it does, theinjector is receiving the proper voltage, so theinjector itself must be faulty.5 Unplug each injector connector, and check

the resistance of the injector (seeillustration). Check your readings with thevalues listed in this Chapter’s Specifications.Renew any that do not give the correctresistance reading.

Volume test6 Because a special injection checker isrequired to test injector volume, thisprocedure is beyond the scope of the homemechanic. Have the injector volume testperformed by a BMW dealer or otherspecialist.

Renewal7 Unplug the main electrical connector for thefuel injector wiring harness. Remove theintake manifold (see Chapter 2A).8 Detach the fuel hoses from the fuel rail, andremove the fuel rail mounting bolts (seeillustration).9 Lift the fuel rail/injector assembly from theintake manifold.10 Unplug the electrical connectors from thefuel injectors. Detach the injectors from thefuel rail.11 Refitting is the reverse of removal. Be sureto renew all O-rings. Coat the O-rings with alight film of engine oil to prevent damageduring refitting. Pressurise the fuel system(refit the fuel pump fuse and switch on theignition) and check for leaks before startingthe engine.

21 Idle air stabiliser valve -check, adjustment andrenewal

41 The idle air stabiliser system works tomaintain engine idle speed within a 200 rpmrange, regardless of varying engine loads atidle. An electrically-operated valve allows asmall amount of air to bypass the throttleplate, to raise the idle speed whenever the idlespeed drops below approximately 750 rpm. Ifthe idle speed rises above approximately 950 rpm, the idle air stabiliser valve closesand stops extra air from bypassing the throttleplate, reducing the idle speed.


20.8 Remove the bolts (arrowed) andseparate the fuel rail and injectors from

the intake manifold

20.5 Check the resistance of each of thefuel injectors

19.6 Check the resistance of thethermotime switch with the engine coolanttemperature below 30º C. There should be

continuity

If you don’t have amechanic’s stethoscope, ascrewdriver can be used tocheck for a clicking sound at

the injectors. Place the tip of thescrewdriver against the injector, andpress your ear against the handle.

2 L-Jetronic systems are equipped with aseparate idle speed control unit (computer)located under the facia. The idle air stabiliservalve has an adjusting screw. Early modelsare equipped with plastic valves, but they stillcan be adjusted by removing the hose andinserting a very thin screwdriver inside.3 Early Motronic systems are also equippedwith a separate idle speed control unit(computer) located under the facia. The idleair stabiliser valve has an adjusting screw.4 On later Motronic systems, the idle airstabiliser valve is ECU-controlled, and noprovision is made for adjustment.

Preliminary check5 Before performing any checks on the idleair stabiliser valve, make sure these criteriaare met:a) The engine must be at operating

temperature (60ºC)b) Turn off all electrical accessories (air

conditioning, heater controls, headlights,auxiliary cooling fan, etc)

c) The throttle position sensor must beoperating correctly (see Chapter 6)

d) There must not be any exhaust leakse) There must not be any vacuum leaksf) Where fitted, the oxygen sensor must be

operating properly (see Chapter 6)6 Connect a tachometer in accordance withthe manufacturer’s instructions.

Caution: The ignition must beswitched off before making anyelectrical connections.

7 The idle air stabiliser valve operatescontinuously when the ignition is on. Start theengine and make sure the valve is vibratingand humming slightly.

L-Jetronic system

Check8 With the engine running, disconnect theelectrical connector from the valve. The idlespeed should increase to about 2,000 rpm.9 If the idle speed does not increase, turn theengine off. Using an ohmmeter, check theresistance across the terminals of the valve

(see illustration). It should be 9 to 10 ohmswith the ambient air temperature at about 20º C.10 Using a pair of jumper wires, apply batteryvoltage to the valve, and confirm that thevalve closes tightly. When the voltage isremoved, the valve should re-open.11 If the idle air stabiliser valve fails any ofthe tests, renew it.12 If the idle air stabiliser valve passes thetests, check the control current.13 Unplug the electrical connector from thevalve. Using a jumper wire, connect oneterminal of the electrical connector to one ofthe terminals on the valve, Connect anammeter (0 to 1000 mA range) between theother terminal on the electrical connector andthe remaining terminal on the valve. Start theengine and allow it to idle. With the enginerunning, the current reading should bebetween 400 and 500 mA. Adjust the valve ifthe current reading is not as specified (seeparagraph 15). Note: The idle air stabilisercurrent will fluctuate between 400 and 1100 mA if the engine is too cold, if thecoolant temperature sensor is faulty, if the idlespeed needs to be adjusted, if there is anengine vacuum leak or if electrical accessoriesare on.14 If there is no current reading, have the idlespeed control unit diagnosed by a BMWdealer or other specialist. Note: The idle airstabiliser control unit (located under the facia)can develop an electrical connector problemthat intermittently turns the valve on and off.Check the connector very carefully beforefitting any new parts. Sometimes, a newcontrol unit will only fix the problemtemporarily.

Adjustment15 With the ignition switched off, connect atachometer in accordance with the equipmentmanufacturer’s instructions.16 Make sure the ignition timing is correct(see Chapter 5).17 Connect an ammeter to the valve (seeparagraph 13).18 With the engine running, the currentreading should be 450 to 470 mA at 850 to

900 rpm (manual transmission), or 460 to 480 mA at 850 to 900 rpm (automatictransmission).19 If the control current is not correct, turnthe adjusting screw until it is within the correctrange (see illustration). Note: On metal-typevalves, the adjusting screw is mountedexternally. On plastic-type valves, theadjustment screw is inside, and can bereached by removing the hose at the end ofthe valve.

Motronic systems

CheckNote: There are two types of idle air stabiliservalve on these systems; early models usuallyhave a two-wire valve, while later models areequipped with a three-wire valve.20 With the engine running, disconnect theelectrical connector from the valve. The idlespeed should increase to about 2000 rpm.21 If the idle speed does not increase:a) Two-wire valve - Using a pair of jumper

wires, apply battery voltage to the valve,and confirm that the valve closes tightly.When the voltage is removed, the valveshould re-open. Also, check theresistance of the valve (see illus-tration 21.9). The resistance should beabout 9 or 10 ohms.

b) Three-wire valve - Turn the engine off andunplug the electrical connector from thevalve. Using an ohmmeter, check theresistance on the two outer terminals ofthe valve. (see illustration). It should beabout 40 ohms. Check the resistance onthe centre and outside terminals of thevalve. They should both be about 20 ohms.

22 If the idle air stabiliser valve fails any ofthe tests, renew it.23 If the idle air stabiliser valve tests are allcorrect, check the control current (two-wirevalve) or the voltage (three-wire valve) asfollows.24 On two-wire valves, connect an ammeter(0 to 1000 mA range) as described inparagraph 13. Start the engine, and allow it toidle. With the engine running, the current


21.21 Check the idle air stabiliser valveresistance on the two outer terminals on

later Motronic systems - it should be about40 ohms

21.19 Location of the adjustment screw onthe metal-type idle air stabiliser valve

(L-Jetronic system)

21.9 Check the resistance of the idle airstabiliser valve - it should typically be 9 to

10 ohms (L-Jetronic system)

4

reading should be between 400 and 500 mA.Adjust the valve if the current reading is not asspecified. Note: The idle air stabiliser currentwill fluctuate between 400 and 1100 mA if theengine is too cold, if the coolant temperaturesensor is faulty, if there is an engine vacuumleak, or if electrical accessories are on.25 If there is no current reading, have the idlespeed control unit (under the facia) checkedby a BMW dealer or other specialist.26 On three-wire valves, check for voltage atthe electrical connector. With the ignition on,there should be battery voltage present at thecentre terminal (see illustration). Thereshould be about 10 volts between the centreterminal and each of the outer terminals.27 If there is no voltage reading, have the idlespeed control unit (early models) or the ECU(later models) checked by a dealer servicedepartment or other specialist.

Adjustment (early models only)28 With the ignition switched off, connect atachometer in accordance with the equipmentmanufacturer’s instructions.29 Make sure the ignition timing is correct(see Chapter 5).30 Connect an ammeter to the valve asdescribed in paragraph 13.31 With the engine running, the current drawshould be 450 to 470 mA at 700 to 750 rpm.32 If the control current is not correct, turnthe adjusting screw until it is within thespecified range. Note: Turn the idle air bypassscrew clockwise to increase the current, oranti-clockwise to decrease the current.

Renewal33 Remove the electrical connector and thebracket from the idle air stabiliser valve.Remove the valve, disconnecting the hoses.34 Refitting is the reverse of removal.

22 Exhaust system servicing -general information

Warning: Inspect or repairexhaust system components onlywhen the system is completelycool. When working under the

vehicle, make sure it is securelysupported.

Silencer and pipes1 The exhaust system consists of the exhaustmanifold, catalytic converter, silencers, and allconnecting pipes, brackets, mountings (seeillustration) and clamps. The exhaust systemis attached to the body with brackets andrubber mountings. If any of the parts areimproperly fitted, excessive noise andvibration may be transmitted to the body.2 Inspect the exhaust system regularly. Lookfor any damaged or bent parts, open seams,holes, loose connections, excessivecorrosion, or other defects which could allowexhaust fumes to enter the vehicle. Generally,deteriorated exhaust system componentscannot be satisfactorily repaired; they shouldbe renewed.

3 If the exhaust system components areextremely corroded or rusted together, it maybe necessary to cut off the old componentswith a hacksaw. Be sure to wear safetygoggles to protect your eyes from metalchips, and wear work gloves to protect yourhands.4 Here are some simple guidelines to followwhen repairing the exhaust system:a) Work from the back to the front of the

vehicle when removing exhaust systemcomponents.

b) Apply penetrating oil to the exhaustsystem nuts and bolts to make themeasier to remove.

c) Use new gaskets, mountings and clampswhen fitting exhaust system components.

d) Apply anti-seize compound to the threadsof all exhaust system nuts and boltsduring reassembly.

e) Be sure to allow sufficient clearancebetween newly-fitted parts and all pointson the underbody, to avoid overheatingthe floorpan, and possibly damaging theinterior carpet and insulation. Payparticularly close attention to the catalyticconverters and heat shields. Also, makesure that the exhaust will not come intocontact with suspension parts, etc.

Catalytic converter5 Although the catalytic converter is anemissions-related component, it is discussedhere because, physically, it’s an integral partof the exhaust system. Always check theconverter whenever you raise the vehicle toinspect or service the exhaust system.6 Raise and support the vehicle.7 Inspect the catalytic converter for cracks ordamage.8 Check the converter connections fortightness.9 Check the insulation covers welded onto thecatalytic converter for damage or a loose fit.

Caution: If an insulation cover isdented so that it touches theconverter housing inside,excessive heat may betransferred to the floor.

10 Start the engine and run it at idle speed.Check all converter connections for exhaustgas leakage.


22.1 A typical exhaust system rubbermounting

21.26 Check for battery voltage on thecentre terminal

Fuel injection system - fault findingL-Jetronic fuel injection system

Engine difficult to start, or fails to start (when cold)Probable cause Corrective actionCold start injector or thermotime switch faulty Test cold start injector and thermotime switch. Renew faulty components (see Section 19)Fuel pump inoperative Check fuel pump fuse and fuel pump relay (see Sections 3 and 4)Airflow meter flap (door) binding or stuck

in open position Inspect the airflow meter for damage (see Section 16)Fuel pressure incorrect Test system pressure (see Section 3). Test fuel pressure regulator (Section 18)Intake air leaks Inspect all vacuum lines, air ducts, and oil filler and dipstick sealsFuel injectors clogged or not operating Check fuel injectors (see Section 20) and wiring harness Coolant temperature sensor faulty or

wiring problem Test coolant temperature sensor (see Chapter 6, Section 4)Throttle position sensor (TPS) incorrectly adjusted Check TPS adjustment (see Chapter 6, Section 4)Incorrect ignition timing Check ignition timing (see Chapter 5). Check vacuum advance systemDirt or other contaminants in fuel Check the fuel and drain the tank if necessaryFaulty ECU Have the ECU tested at a dealer service department or other specialist

Engine difficult to start, or fails to start (when warm)Probable cause Corrective actionCold start injector leaking or operating continuously Test cold start injector and thermotime switch (see Section 19)Fuel pressure incorrect Test fuel pump(s). Renew if necessary (see Section 3)Insufficient residual fuel pressure Test residual fuel pressure. Renew fuel pump or fuel accumulator as necessary

(see Section 18)Fuel leak(s) Inspect fuel lines and fuel injectors for leaks. Correct leaks as required (see Chapter 4)Coolant temperature sensor faulty or

wiring problem Test coolant temperature sensor (see Chapter 6, Section 4)Vapour lock (warm weather) Check fuel pressure (see Section 3)EVAP system faulty (where applicable) Check EVAP system (see Chapter 6, Section 6)Incorrect ignition timing Check ignition timing (see Chapter 5). Check vacuum advance systemFaulty ECU Have the ECU tested at a dealer service department or other specialistIdle speed control system faulty Test the idle air stabiliser valve (see Section 21)

Engine misses and hesitates under loadProbable cause Corrective actionFuel injector clogged or faulty Test fuel injectors. Check for clogged injector lines. Renew faulty injectors (see Section 20)Fuel pressure incorrect Test fuel system pressure (see Section 3). Test fuel pressure regulator (see Section 18)Fuel leak(s) Inspect fuel lines and fuel injectors for leaks (see Chapter 4)Engine maintenance Tune-up engine (see Chapter 1). Check the distributor cap, rotor, HT leads and spark

plugs, and renew any faulty componentsAirflow meter flap (door) binding, or

stuck in open position Inspect the airflow meter for damage (see Section 16)Intake air leaks Inspect all vacuum lines, air ducts and oil filler and dipstick seals

Engine has erratic idle speedProbable cause Corrective actionIdle air stabiliser valve faulty Check the idle air stabiliser valve (see Section 21)No power to the idle air stabiliser valve Check the idle air stabiliser relay and wiring circuit (see Chapter 12)Vacuum advance system faulty Check vacuum advance system and electronic vacuum advance relayIdle speed control unit faulty Have the idle speed control unit checked by a dealer

Motronic fuel injection systemNote: With this system, when faults occur, the ECU stores a fault code in its memory. These codes can only be read by a BMW dealer, asspecialised equipment is required. It may save time to have at least the initial fault diagnosis carried out by a dealer.

Lack of powerProbable cause Corrective actionCoolant temperature sensor faulty, Test coolant temperature sensor and wiring. Repair wiring or renew sensor if

or wire to sensor broken faulty (see Chapter 6)Fuel pressure incorrect Check fuel pressure from main pump and transfer pump, as applicable (see Section 3)Throttle plate not opening fully Check accelerator cable adjustment to make sure throttle is opening fully. Adjust cable if

necessary (see Section 9)


4

Engine difficult to start, or fails to start (when cold)Probable cause Corrective actionCold start injector or thermotime switch

faulty (early Motronic system only) Test cold start injector and thermotime switch. Renew faulty components (see Section 19)Fuel pump not running Check fuel pump fuse and fuel pump relay (see Sections 2 and 3)Airflow meter flap (door) binding, or

stuck in open position Inspect the airflow meter for damage (see Section 16)Fuel pressure incorrect Test system pressure (see Section 3)Intake air leaks Inspect all vacuum lines, air ducts and oil filler and dipstick sealsFuel injectors clogged or not operating Check fuel injectors (see Section 20) and wiring harness Coolant temperature sensor faulty or Test coolant temperature sensor (see Chapter 6, Section 4)

wiring problemTPS (throttle position sensor) incorrectly adjusted Check TPS adjustment (see Chapter 6, Section 4)Dirt or other contaminants in fuel Check the fuel and drain the tank if necessaryFaulty ECU Have the ECU tested at a dealer service department or other specialistCrankshaft position signal missing Faulty position sensor or flywheel, or reference pin missing (see Chapter 5)

Engine difficult to start, or fails to start (when warm)Probable cause Corrective actionCold start injector leaking or operating

continuously (early Motronic system only) Test cold start injector and thermotime switch (see Section 19)Fuel pressure incorrect Test fuel pressure (see Section 3) Insufficient residual fuel pressure Test fuel system hold pressure (see Section 3)Fuel leak(s) Inspect fuel lines and fuel injectors for leaks. Correct leaks as necessaryCoolant temperature sensor faulty

or wiring problem Test coolant temperature sensor (see Chapter 6, Section 4)Vapour lock (in warm weather) Check fuel pressure (see Section 3)EVAP system faulty Check EVAP system (see Chapter 6, Section 6)Faulty ECU Have the ECU tested at a dealer service department or other specialistIdle speed control system faulty Test the idle air stabiliser valve (see Section 21)

Oxygen sensor faulty (where applicable) Check the oxygen sensor (see Chapter 6, Section 4)

Engine misses and hesitates under loadProbable cause Corrective actionFuel injector clogged Test fuel injectors. Check for clogged injector lines. Renew faulty injectors (see Section 20)Fuel pressure incorrect Test fuel system pressure (see Section 3). Test fuel pressure regulator (see Section 18)Fuel leak(s) Inspect fuel lines and fuel injectors for leaks (see Chapter 4)Engine maintenance Tune-up engine (see Chapter 1). Check the distributor cap, rotor, HT leads and spark

plugs, and renew any faulty componentsAirflow meter flap (door) binding, or Inspect the airflow meter for damage (see Section 16)

stuck in open positionIntake air leaks Inspect all vacuum lines, air ducts, and oil filler and dipstick sealsThrottle position sensor (TPS) incorrectly adjusted Check TPS adjustment (see Chapter 6)

Engine idles too fastProbable cause Corrective actionAccelerator pedal, cable or throttle valve binding Check for worn or broken components, kinked cable, or other damage. Renew faulty

componentsAir leaking past throttle valve Inspect throttle valve, and adjust or renew as required

Engine has erratic idle speedProbable cause Corrective actionIdle air stabiliser valve faulty Check the idle air stabiliser valve (see Section 21)No power to the idle air stabiliser valve Check the idle air stabiliser relay and wiring circuit (see Chapter 12)Idle speed control unit faulty Have the idle speed control unit checked by a dealer

Poor fuel economyProbable cause Corrective actionCold start injector leaking

(early Motronic system only) Test and, if necessary, renew cold start injector (see Section 19)Oxygen sensor faulty (where applicable) Test the oxygen sensor (see Chapter 6, Section 4))Sticking handbrake/binding brakes Check the handbrake/braking system (see Chapter 9)Tyre pressures low Check tyre pressures (Chapter 1)


5GeneralApplication

Models with carburettor or L-Jetronic fuel injection . . . . . . . . . . . . . . Transistorised Coil Ignition (TCI) systemModels with Motronic fuel injection . . . . . . . . . . . . . . . . . . . . . . . . . . Ignition functions controlled by Motronic system

Ignition coilPrimary resistance

TCI system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.82 ohmsMotronic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.50 ohms

Secondary resistanceTCI system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8250 ohmsMotronic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5000 to 6000 ohms

Distributor (models with TCI system)Air gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 mm to 0.7 mmPick-up coil/impulse generator resistance . . . . . . . . . . . . . . . . . . . . . . . 900 to 1200 ohms

Ignition timing (models with TCI system)(Vacuum line disconnected at distributor)316 with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25º BTDC at 2500 rpm (2900 rpm from 9/83)318i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30º BTDC at 3000 rpm320i with M20/B20 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23º BTDC at 5000 ±50 rpm518 with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25º BTDC at 2900 ±50 rpm518i with M10/B18 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30º BTDC at 3000 ±50 rpm525i with M30/B25 engine (except distributor

237 302 033) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22º BTDC at 1800 ±50 rpm525i with M30/B25 engine (distributor 237 302 033) . . . . . . . . . . . . . . . 22º BTDC at 2150 ±50 rpm528i with M30/B28 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22º BTDC at 2150 ±50 rpm

Chapter 5 Engine electrical systems

Air gap (TCI system) – check and adjustment . . . . . . . . . . . . . . . . . . 11Alternator – removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Alternator brushes – check and renewal . . . . . . . . . . . . . . . . . . . . . . 17Battery – emergency jump starting . . . . . . . . . . . . . . . . . . . . . . . . . . 2Battery – removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Battery cables – check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . 4Battery check and maintenance . . . . . . . . . . . . . . . . See Chapter 1Charging system – check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Charging system – general information and precautions . . . . . . . . . 13Distributor – removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Drivebelt check, adjustment and renewal . . . . . . . . . See Chapter 1General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Ignition coil – check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Ignition sensors (Motronic system) – check and renewal . . . . . . . . . 12Ignition system – check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Ignition system – general information and precautions . . . . . . . . . . 5Ignition timing (TCI system) – check and adjustment . . . . . . . . . . . . 7Impulse generator and ignition control unit – check and

renewal (TCI system) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Spark plug HT lead check and renewal . . . . . . . . . . . See Chapter 1Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Starter motor – in-vehicle check . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Starter motor – removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 20Starter solenoid – removal and refitting . . . . . . . . . . . . . . . . . . . . . . 21Starting system – general information and precautions . . . . . . . . . . 18Voltage regulator – renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5•1







Specifications

Contents


The engine electrical systems include allignition, charging and starting components.Because of their engine-related functions,these components are discussed separatelyfrom body-related electrical devices such asthe lights, the instruments, etc. (which areincluded in Chapter 12).

Always observe the following precautionswhen working on the electrical systems:a) Be extremely careful when servicing

engine electrical components. They areeasily damaged if improperly checked,connected or handled.

b) Never leave the ignition switched on forlong periods of time with the engine off.

c) Don’t disconnect the battery cables whilethe engine is running.

d) Observe the rules when jump-startingyour vehicle. Read the precautions at thefront of this manual.

e) Always disconnect the battery negativecable first, and connect it last, to reducethe risk of accidental short-circuits.

f) Don’t charge the battery with the cablesconnected to the terminals.

It’s also a good idea to review the safety-related information regarding the engineelectrical systems in the “Safety first” sectionnear the front of this manual before beginningany operation included in this Chapter.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

2 Battery - emergency jump starting 1

Refer to the “Jump starting” procedure atthe front of this manual.

3 Battery - removal and refitting 1Note: Depending on the model, the batterymay be located in the engine compartment, inthe rear luggage compartment, or under therear seat. Consult your owners handbook forthe location of the battery, if not alreadyknown to you.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable.2 Detach the cable from the positive terminal.3 Remove the battery hold-down bracket(see illustrations) and lift out the battery. Becareful - it’s heavy. Do not tilt the battery toany extent while it is being removed, andstore it upright.4 While the battery is out, inspect the carrier(tray) for corrosion (see Chapter 1).5 If you are renewing the battery, make surethat you get one that’s identical, with thesame dimensions, amperage rating, coldcranking rating, etc.6 Refitting is the reverse of removal.

4 Battery cables - check and renewal 1

Check1 Periodically inspect the entire length ofeach battery cable for damage, cracked orburned insulation, and corrosion. Poor battery cable connections can causestarting problems and decreased engineperformance.



2 Check the cable-to-terminal connections atthe ends of the cables for cracks, loose wirestrands, and corrosion. The presence ofwhite, fluffy deposits under the insulation atthe cable terminal connection is a sign thatthe cable is corroded, and should be cleanedor renewed. Check the terminals fordistortion, missing mounting bolts, andcorrosion.

Renewal3 When removing the cables, alwaysdisconnect the negative cable first andconnect it up last. This reduces the risk ofaccidental short-circuits. Even if only a newpositive cable is being fitted, be sure todisconnect the negative cable from thebattery first (see Chapter 1 for furtherinformation regarding battery cable removal).4 Disconnect the old cables from the battery,then trace each of them to their opposite endsand detach them from the starter solenoidand earth terminals. Note the routing of eachcable to ensure correct refitting.5 If the old cables are to be renewed, takethem with you when buying new cables. It isvitally important that you renew the cableswith identical parts. Cables have character-istics that make them easy to identify: positivecables are usually red, larger in cross-section,and have a larger-diameter battery postclamp; earth cables are usually black, smallerin cross-section, and have a slightly smallerdiameter clamp for the negative post.6 Clean the threads of the solenoid or earthconnection with a wire brush to remove rustand corrosion.

7 Attach the cable to the solenoid or earthconnection, and tighten the mounting nut/boltsecurely.8 Before connecting a new cable to thebattery, make sure that it reaches the batterypost without having to be stretched.9 Connect the positive cable first, followed bythe negative cable.

5•2 Engine electrical systems

3.3b The battery is mounted under therear seat on some models

3.3a Always detach the cable from thebattery negative terminal first, then detach

the positive cable – to remove the hold-down assembly, remove the nuts (arrowed)

or single bolt

Apply a light coat of batteryterminal corrosion inhibitor,or petroleum jelly, to theterminal threads, to preventfuture corrosion.

5 Ignition system - generalinformation and precautions

The ignition system includes the ignitionswitch, the battery, the distributor, the primary(low-voltage/low-tension or LT) andsecondary (high-voltage/high-tension or HT)wiring circuits, the spark plugs and the sparkplug leads. Models fitted with a carburettor orL-Jetronic fuel injection are equipped with aTransistorised Coil Ignition (TCI) system.Models fitted with the Motronic fuel injectionsystem have the ignition system incorporatedwithin the Motronic system (Digital MotorElectronics or DME).

Transistorised Coil Ignition (TCI)system

This system is has four major components;the impulse generator, the ignition controlunit, the coil, and the spark plugs. Theimpulse generator provides a timing signal forthe ignition system. Equivalent to cam-actuated breaker points in a standarddistributor, the impulse generator creates anA/C voltage signal every time the triggerwheel tabs pass the impulse generator tabs.When the ignition control unit (capacitivedischarge unit) receives the voltage signal, ittriggers a spark discharge from the coil byinterrupting the primary coil circuit. Theignition dwell (coil charging time) is adjustedby the ignition control unit for the mostintense spark. Note: The air gap (distancebetween the impulse generator and triggerwheel tabs) can be adjusted (see Section 11).

Ignition timing is mechanically adjusted(see Section 7). A centrifugal advance unitthat consists of spring-loaded rotatingweights advances ignition timing as enginespeed increases. The vacuum advanceadjusts ignition timing to compensate forchanges in engine load.

Motronic ignition systemThis system, also known as Digital Motor

Electronics (DME), incorporates all ignitionand fuel injection functions into one centralcontrol unit or ECU (computer). The ignitiontiming is based on inputs the ECU receives forengine load, engine speed, coolanttemperature and intake air temperature. Theonly function the distributor performs is thedistribution of the high voltage signal to theindividual spark plugs. The distributor isattached directly to the cylinder head. There isno mechanical spark advance system used onthese systems.

Ignition timing is electronically-controlled,and is not adjustable on Motronic systems.During starting, a crankshaft position sensor(reference sensor) relays the crankshaftposition to the ECU, and an initial baselineignition point is determined. Once the engine

is running, the ignition timing is continuallychanging, based on the various input signalsto the ECU. Engine speed is signalled by aspeed sensor. Early Motronic systems havethe position reference sensor and the speedsensor mounted on the bellhousing over theflywheel on the left-hand side. Later Motronicsystems have a single sensor (pulse sensor)mounted over the crankshaft pulley. Thissensor functions as a speed sensor as well asa position reference sensor. Refer to Sec-tion 12 for checking and renewing the ignitionsensors. Note: Some models are equippedwith a TDC sensor mounted on the front of theengine. This sensor is strictly for the BMWservice test unit, and it is not part of theMotronic ignition system.

PrecautionsCertain precautions must be observed

when working on a transistorised ignitionsystem.a) Do not disconnect the battery cables

when the engine is runningb) Make sure the ignition control unit (TCI

ignition system) is always well earthed(see Section 10).

c) Keep water away from the distributor andHT leads.

d) If a tachometer is to be connected to theengine, always connect the tachometerpositive (+) lead to the ignition coilnegative terminal (-) and never to thedistributor.

e) Do not allow the coil terminals to beearthed, as the impulse generator or coilcould be damaged.

f) Do not leave the ignition switch on formore than ten minutes with the engineoff, or if the engine will not start.

6 Ignition system - check 2Warning: Because of the highvoltage generated by the ignitionsystem, extreme care should betaken whenever an operation is

performed involving ignition components.This not only includes the impulsegenerator (electronic ignition), coil,distributor and spark plug HT leads, butrelated components such as spark plugconnectors, tachometer and other testequipment.

1 If the engine turns over but will not start,disconnect the spark plug HT lead from anyspark plug, and attach it to a calibrated sparktester (available at most car accessory shops). Note: There are two different types of sparktesters. Be sure to specify electronic(breakerless) ignition. Connect the clip on the

tester to an earth point such as a metalbracket (see illustration).2 If you are unable to obtain a calibratedspark tester, remove the spark plug HT leadfrom one of the spark plugs. Using aninsulated tool, hold the lead about a quarter-inch from the engine block - make sure thegap is not more than a quarter-inch, ordamage may be caused to the electroniccomponents.3 Crank the engine, and observe the tip of thetester or spark plug HT lead to see if a sparkoccurs. If bright-blue, well-defined sparksoccur, sufficient voltage is reaching the plugsto fire the engine. However, the plugsthemselves may be fouled, so remove andcheck them as described in Chapter 1.4 If there’s no spark, check another HT leadin the same manner. A few sparks followed byno spark is the same condition as no spark atall.5 If no spark occurs, remove the distributorcap, and check the cap and rotor asdescribed in Chapter 1. If moisture is present,use a water-dispersant aerosol (or somethingsimilar) to dry out the cap and rotor, then refitthe cap and repeat the spark test.6 If there’s still no spark, disconnect the coilHT lead from the distributor cap, and test this lead as described for the spark plugleads.7 If no spark occurs, check the primary wireconnections at the coil to make sure they’reclean and tight. Make any necessary repairs,then repeat the check.8 If sparks do occur from the coil HT lead, thedistributor cap, rotor, plug HT lead(s) or sparkplug(s) may be defective. If there’s still nospark, the coil-to-cap HT lead may bedefective. If a substitute lead doesn’t makeany difference, check the ignition coil (seeSection 9). Note: Refer to Sections 10 and 11for more test procedures on the distributorsfitted with the TCI ignition system.

Engine electrical systems 5•3

6.1 To use a spark tester, simplydisconnect a spark plug HT lead, clip thetester to a convenient earth (like a valve

cover bolt or nut) and operate the starter –if there is enough power to fire the plug,

sparks will be visible between theelectrode tip and the tester body

5

7 Ignition timing (TCI system) -check and adjustment 4

Warning: Keep hands, equipmentand wires well clear of theviscous cooling fan duringadjustment of the ignition timing.

Note: This Section describes the procedurefor checking and adjusting the ignition timingon engines fitted with the TCI system. Onengines fitted with the Motronic enginemanagement system, the ignition timing iscontrolled by the electronic control unit, andno adjustment is possible. The timing can bechecked using the following procedure, but noignition timing values were available at thetime of writing. If the timing is thought to beincorrect, refer to a BMW dealer.1 Some special tools are required for thisprocedure (see illustration). The engine mustbe at normal operating temperature, and theair conditioning (where fitted) must beswitched off. Make sure the idle speed iscorrect.2 Apply the handbrake, and chock the wheelsto prevent movement of the vehicle. Thetransmission must be in neutral (manual) orPark (automatic).3 The timing marks are located on the engineflywheel (viewed through the timing check

hole in the bellhousing) and/or on the vibrationdamper on the front of the engine.4 Where applicable, disconnect the vacuumhose from the distributor vacuum advanceunit.5 Connect a tachometer and timing lightaccording to the equipment manufacturer’sinstructions (an inductive pick-up timing lightis preferred). Generally, the power leads forthe timing light are attached to the batteryterminals, and the pick-up lead is attached tothe No 1 spark plug HT lead. The No 1 sparkplug is the one at the front of the engine.

Caution: If an inductive pick-uptiming light isn’t available, don’tpuncture the spark plug HT leadto attach the timing light pick-up

lead. Instead, use an adapter between thespark plug and HT lead. If the insulation onthe HT lead is damaged, the secondaryvoltage will jump to earth at the damagedpoint, and the engine will misfire.Note: On some models, a TDC transmitter isfitted for checking the ignition system.However, a special BMW tester must beconnected to the diagnostic socket to use it,so unless the special tester is available, aconventional timing light should be used. Theignition timing mark may be on the vibrationdamper, but if not, normally the TDC mark willbe. If the timing light is of the adjustable delaytype, then the ignition timing may bedetermined by zeroing the adjustment, thenturning the adjustment until the TDC marks arealigned, and then reading off the amount ofadvance from the timing light. If a standardtiming light is being used, make a mark on thevibration damper in accordance with thespecified advance, using the following formulato calculate the distance from the TDC markto the timing mark:

Distance = 2Pr x advance360

where P = 3.142r = radius of vibration damperadvance = specified advance

BTDC in degrees6 With the ignition off, loosen the distributorclamp nut just enough to allow the distributorto pivot without any slipping.

7 Make sure the timing light wires are routedaway from the drivebelts and fan, then startthe engine.8 Raise the engine rpm to the specifiedspeed, and then point the flashing timing lightat the timing marks - be very careful of movingengine components.9 The mark on the flywheel or vibrationdamper will appear stationary. If it’s alignedwith the specified point on the bellhousing orengine front cover, the ignition timing iscorrect (see illustrations).10 If the marks aren’t aligned, adjustment isrequired. Turn the distributor very slowly untilthe marks are aligned, taking care not totouch the HT leads.11 Tighten the nut on the distributor clamp,and recheck the timing.12 Switch off the engine, and remove thetiming light and tachometer. Reconnect thevacuum hose where applicable.

8 Distributor - removal and refitting 4

TCI system

Removal1 After carefully marking them for position,remove the coil HT lead and spark plug HTleads from the distributor cap (see Chapter 1).2 Remove No 1 spark plug (the one nearestyou when you are standing in front of theengine).3 Manually rotate the engine to Top DeadCentre (TDC) on the compression stroke forNo 1 piston (see Chapter 2A)4 Carefully mark the vacuum hoses, if morethan one is present on your distributor.5 Disconnect the vacuum hose(s).6 Disconnect the primary circuit wires fromthe distributor.7 Mark the relationship of the rotor tip to thedistributor housing (see illustration). Alsomark the relationship of the distributorhousing to the engine.


7.1 Tools for checking and adjusting theignition timing

1 Vacuum plugs - Vacuum hoses will, inmost cases, have to be disconnected andplugged. Moulded plugs in various shapesand sizes can be used for this, if wished

2 Inductive pick-up timing light - Flashes abright, concentrated beam of light when No 1 spark plug fires. Connect the leadsaccording to the instructions supplied withthe light

3 Distributor spanner - On some models,the hold-down bolt for the distributor isdifficult to reach and turn with conventionalspanners or sockets. A special spanner likethis must be used

7.9a Flywheel “OT” timing mark 7.9b Flywheel “OZ” timing mark

8 Remove the hold-down nut or bolt andclamp.9 Remove the distributor. Note: Do not rotatethe engine with the distributor out.

Refitting10 Before refitting the distributor, makecertain No 1 piston is still at TDC on thecompression stroke.11 Insert the distributor into the engine, withthe adjusting clamp centred over the hold-down hole. Make allowance for the gear toturn as the distributor is inserted.12 Refit the hold-down nut or bolt. The markspreviously made on the distributor housing,and on the rotor and engine, should line upbefore the nut or bolt is tightened.13 Refit the distributor cap.14 Connect the wiring for the distributor.15 Reconnect the spark plug HT leads.16 Reconnect the vacuum hoses aspreviously marked.17 Check the ignition timing (see Section 7).

Motronic systemRemoval18 Remove the cover from the distributor(see illustration) and remove the distributorcap (see Chapter 1).19 Using a small Allen key, remove the threescrews from the rotor (see illustration).20 Remove the rotor.Refitting21 Refitting is the reverse of removal.

9 Ignition coil -check and renewal 2

Caution: Do not earth the coil, asthe coil and/or impulse generatorcould be damaged.

Note: On models equipped with the Motronicsystem, a faulty ECU can cause the ignitioncoil to become damaged. Be sure to test theignition coil if the engine will not start and anECU fault is suspected.1 Mark the wires and terminals for position,then remove the primary circuit wires and theHT lead from the coil.

2 Remove the coil assembly from itsmounting, then clean the outer casing andcheck it for cracks and other damage.3 Inspect the coil primary terminals and thecoil tower terminal for corrosion. Clean themwith a wire brush if any corrosion is found.4 Check the coil primary resistance byattaching an ohmmeter to the primaryterminals (see illustrations). Compare themeasured resistance to the Specificationslisted in this Chapter.5 Check the coil secondary resistance byconnecting one of the ohmmeter leads to oneof the primary terminals, and the otherohmmeter lead to the coil high-tensionterminal (see illustrations). On TCI systems,


8.19 Remove the rotor screws (arrowed)with an Allen key, and pull the rotor off the

shaft

8.18 Remove the three bolts (arrowed)from the distributor cap

8.7 Mark the relationship of the rotor tothe distributor housing (arrowed)

9.5b Using an ohmmeter, measure thesecondary resistance of the coil (later

Motronic system)

9.5a Using an ohmmeter, measure thesecondary resistance of the coil (TCI

system)

9.4b Some Motronic systems use adifferent type of coil. First, remove the coil

cover and . . .

9.4a Using an ohmmeter, measure theresistance between the primary terminals

of the ignition coil (TCI system shown)

9.4c . . . using an ohmmeter, measure theresistance between the primary terminals

of the coil

5

connect the ohmmeter to coil terminal 1 (-)and the centre tower. On Motronic systems,connect the ohmmeter to coil terminal 15 (+)and the centre tower. Compare the measuredresistance with the values given in the Specifi-cations in this Chapter.6 If the measured resistances are not close tothose specified, the coil is defective andshould be renewed. Note that the measuredresistance will vary according to thetemperature of the coil, so don’t rush tocondemn the coil if the resistance is only alittle way out.7 It is essential for proper ignition systemoperation that all coil terminals and wire leadsbe kept clean and dry.8 Refit the coil in its mounting, and reconnectthe wiring. Refitting is the reverse of removal.

10 Impulse generator andignition control unit - checkand renewal (TCI system)

31 The impulse generator (located in thedistributor) and ignition control unit need to betested in the event there is no spark at thespark plugs. Make sure the plug leads,ignition coil and spark plugs are workingproperly (see Sections 6 and 9). There are twotypes of control units; Bosch orSiemens/Telefunken. The two types (seeillustration) can be distinguished by theirelectrical connectors. The Bosch type uses asingle, large rectangular connector at thebottom of the unit, while theSiemens/Telefunken control unit uses tworound electrical connectors at the front of theunit.

CheckVoltage supply and earth to ignitioncontrol unit2 With the ignition off, remove the harnessconnectors from the ignition control unit (seeillustrations). Connect a voltmeter betweenconnector terminals 2 and 4 on Boschsystems, or between terminals 6 and 3 onSiemens/Telefunken systems.3 Turn the ignition on. There should bebattery voltage on the designated terminals. Ifthere is no voltage, check the wiring harnessfor an open-circuit (see Chapter 12).4 Using an ohmmeter, check for continuitybetween connector terminal 2 (Bosch) or 6(Siemens/Telefunken) and the earth to thevehicle body. Continuity should exist.5 Using an ohmmeter, check for continuitybetween connector terminal 4 (Bosch) or 3(Siemens/Telefunken) and terminal 15 of theignition coil. Continuity should exist.6 If the readings are incorrect, repair thewiring harness.Impulse generator signal7 If the ignition control unit is receivingbattery voltage, check the A/C signal voltagecoming from the impulse generator to thecontrol unit.


10.2b Check for voltage at terminals 6 and3 on the control unit electrical connector

(Siemens/Telefunken system shown)

10.2a Check for voltage at terminals 2 and4 on the control unit electrical connector

(Bosch system shown)

1 Coil HT lead2 Ignition coil3 Spark plug HT lead4 Spark plug5 Ignition control unit (Bosch)6 Ignition control unit

(Siemens/Telefunken)7 Wiring harness

8 Distributor housing with centrifugal advance counterweights

9 Vacuum diaphragm10 Circlip11 Impulse generator12 Trigger wheel13 Circlip14 Dust shield

15 Ignition rotor16 Distributor17 Roll pin18 Trigger wheel and impulse

generator tabs19 Cap retaining clip20 Impulse generator

connector

10.1 Schematic of the ignition components used on engines with the TCI system

8 Use a digital voltmeter for the followingtests:a) On Bosch systems, connect the positive

probe to connector terminal 5, and thenegative probe to terminal 6 (seeillustration).

b) On Siemens/Telefunken systems, connectthe positive probe to terminal (+) of thesmaller connector, and the negativeprobe to terminal (-).

9 Have an assistant crank the engine over,and check that there is 1 to 2 volts A/Cpresent. If there is no voltage, check thewiring harness between the impulse generator(in the distributor) and the control unit. If theharness is OK, check the impulse generatorresistance.

Warning: Do not crank theengine over for an excessivelength of time. If necessary,disconnect the cold start injector

electrical connector (see Chapter 4) tostop the flow of fuel into the engine.10 To check the resistance in the impulsegenerator, proceed as described for yoursystem below:a) On Bosch units, measure the resistance

between connector terminals 5 and 6(see illustration 10.8). The readingshould be 1000 to 1200 ohms.

b) On Siemens/Telefunken units, measurethe resistance between the terminals ofthe smaller connector. The reading shouldbe 1000 to 1200 ohms.

11 If the resistance readings are incorrect,renew the impulse generator. If the resistancereadings for the impulse generator are correctand the control unit voltages (supply voltage[paragraphs 1 to 6] and signal voltage[paragraphs 7 to 9]) are incorrect, renew thecontrol unit.

RenewalIgnition control unit12 Make sure the ignition is switched off.13 Disconnect the electrical connector(s)from the control unit.14 Remove the mounting screws from thecontrol unit, and lift it from the enginecompartment.

15 Refitting is the reverse of removal. Note:On Bosch control units, a special dielectricgrease is used between the heat sink and theback of the control unit. In the event the twoare separated (renewal or testing) the oldgrease must be removed, and the heat sinkcleaned off using 180-grit sandpaper. ApplyCuril K2 (Bosch part number 81 22 9 243). Asilicon dielectric compound can be used as asubstitute. This treatment is very important forthe long life of these expensive ignition parts.

Impulse generatorCaution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code

before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.16 Disconnect the battery negative cable.17 Remove the distributor from the engine(see Section 8).18 Using a pair of circlip pliers, remove thecirclip retaining the trigger wheel (seeillustration).19 Use two flat-bladed screwdriverspositioned at opposite sides of the triggerwheel, and carefully prise it up (seeillustration). Note: Push the screwdrivers inas far as possible without bending the triggerwheel. Prise only on the strongest, centreportion of the trigger wheel. In the event thetrigger wheel is bent, it must be replaced witha new one. Note: Be sure not to lose the rollpin when lifting out the trigger wheel.20 Remove the mounting screws from theimpulse generator electrical connector, thevacuum diaphragm and the baseplate.21 Remove the two screws from the vacuumadvance unit, and separate it from thedistributor by moving the assembly downwhile unhooking it from the baseplate pin.22 Use circlip pliers to remove the circlip thatretains the impulse generator and thebaseplate assembly.23 Carefully remove the impulse generatorand the baseplate assembly as a single unit.

24 Remove the three screws, and separatethe baseplate assembly from the impulsegenerator.25 Refitting is the reverse of removal. Note:Be sure to position the insulating ring betweenthe generator coil and the baseplate. It mustbe centred before tightening the mountingscrews. Also, it will be necessary tocheck/adjust the air gap if the trigger wheelhas been removed, or tampered with to thepoint that the clearance is incorrect (seeSection 11).

11 Air gap (TCI system) - check and adjustment 2


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable.2 Insert a brass feeler gauge between thetrigger wheel tab and the impulse generator(see illustration). Slide the feeler gauge up


10.19 Carefully prise the trigger wheel offthe distributor shaft

10.18 Use circlip pliers and remove thecirclip from the distributor shaft

10.8 Back-probe the ignition control unitconnector, and check for signal voltage onterminals 5 and 6 (Bosch system shown). It

is very helpful to use angled probes

11.2 Use a brass feeler gauge to checkthe air gap (be sure the gauge rubs lightly

against the trigger wheel as well as thelocating pin for the correct adjustment)

5

and down - you should feel a slight drag onthe feeler gauge as it is moved if the gap iscorrect. The gap must be as given in thisChapter’s Specifications.3 To adjust the gap, it is necessary to removethe impulse generator and the baseplateassembly from the distributor (see illus-tration 10.1).4 Follow paragraphs 17 to 24 in Section 10and loosen the screws that retain the impulsegenerator to the baseplate assembly.5 Carefully insert the feeler gauge and tightenthe screws.6 Refit the assembly back into the distributorand recheck the adjustment.

12 Ignition sensors (Motronicsystem) - check and renewal 2

Note: Some models are equipped with a TDCsensor mounted on the front of the engine.This sensor is strictly for the BMW service testunit, and is not part of the Motronic ignitionsystem.

Speed and position sensorsCheck1 Locate the two electrical connectors for thesensors (see illustrations). The greyconnector is for the position sensor, and thewhite connector is for the speed sensor.2 Using an ohmmeter, check the resistancebetween terminal 1 (yellow wire) and terminal2 (black wire) on the sensor side of eachconnector. The resistance should be 860 to1,060 ohms.3 Also check the resistance between terminal3 and either terminal 1 or terminal 2. Theresistance should be approximately 100 000ohms.4 If the reading(s) are incorrect, renew thesensor(s).Renewal5 Remove the sensor mounting screw(s),

using an Allen key where necessary, and pullthe sensor(s) from the sockets. Disconnectthe wiring from one sensor at a time - be surethe connectors are not interchanged whenfitting new sensors. The bellhousing is markedwith a B for the position sensor (greyconnector) and D for the speed sensor (blackconnector) (see illustration). Note: It is agood idea to check the condition of the raisedpin on the flywheel while the sensors are outof the sockets. Turn the engine by hand asnecessary to bring the pin into view.6 Tighten the sensor mounting screw(s)securely, but be careful not to overtighten.

Pulse sensor (later models)

Check7 Locate the two electrical connectors for thesensor (see illustrations). Disconnect theelectrical connector from the front. 8 Using an ohmmeter, check resistancebetween terminal 1 (yellow wire) and terminal2 (black wire) on the sensor side of eachconnector (see illustration). The resistanceshould be 500 to 600 ohms.9 If the reading is incorrect, renew the sensor.

Renewal10 Remove the pulse sensor mounting boltusing a 5 mm hex spanner (see illustration).


12.10 The pulse sensor itself (arrowed) islocated on the timing belt cover, to one

side of the pulley (later models)

12.8 The resistance of the pulse sensorshould be 500 to 600 ohms (later models)

12.7b On later 5-Series models, the pulsesensor connector (arrowed) is located next

to the valve cover

12.7a On later 3-Series models, the pulsesensor connector (arrowed) is located next

to the 20-pin diagnostic connector

12.5 Location of the position sensor (B) andspeed sensor (D) on the bellhousing on allMotronic systems – do not interchange the

sensors, or the engine will not start

12.1b Location of the position sensor(grey connector) (A) and the speed sensor(black connector) (B) on Motronic systems

(later models)

12.1a Location of the position sensor (greyconnector) (A) and the speed sensor (blackconnector) (B) on Motronic systems (early

models)

Withdraw the sensor from its bracket andremove it.11 When fitting the new sensor, use a brassfeeler gauge to position the tip of the sensorthe correct distance from the pulse wheel(see illustration).12 Tighten the mounting bolt, but be carefulnot to overtighten it.

13 Charging system - generalinformation and precautions

There are two different types of alternatorfitted on these models; Bosch and Motorola.Also, there are three different amperageratings available; 65A, 80A or 90A. A stampedserial number on the rear of the alternator willidentify the type and amperage rating.Perform the charging system checks (seeSection 14) to diagnose any problems with thealternator.

The voltage regulator and the alternatorbrushes are mounted as a single assembly.On Bosch alternators, this unit can beremoved from the alternator (see Section 16)and the components serviced individually.

The alternator on all models is mounted onthe left front of the engine, and utilises a V-belt and pulley drive system. Drivebelt tensionand battery servicing are the two primarymaintenance requirements for these systems.See Chapter 1 for the procedures regardingengine drivebelt checking and batteryservicing.

The ignition/no-charge warning light shouldcome on when the ignition key is turned toStart, then go off immediately the enginestarts. If it remains on, there is a malfunctionin the charging system (see Section 14). Somevehicles are also equipped with a voltmeter. Ifthe voltmeter indicates abnormally high or lowvoltage, check the charging system (seeSection 14). Note: On models up to 1986, ablown ignition/no-charge warning light willprevent the alternator from charging. After1987, a resistor is wired in parallel with thewarning light in order to allow current to

bypass the light in the event of a broken circuit(blown warning light).

PrecautionsBe very careful when making electrical

circuit connections to the alternator, and notethe following:a) When reconnecting wires to the alternator

from the battery, be sure to note thepolarity.

b) Before using arc-welding equipment torepair any part of the vehicle, disconnectthe wires from the battery terminals andfrom the alternator.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.c) Never start the engine with a battery

charger connected. Always disconnectboth battery cables before using a batterycharger.

d) Never disconnect cables from the batteryor from the alternator while the engine isrunning.

e) The alternator is turned by an enginedrivebelt. Serious injury could result ifyour hands, hair or clothes becomeentangled in the belt with the enginerunning.

f) Because the alternator is connecteddirectly to the battery, take care not toshort out the main terminal to earth.

g) Wrap a plastic bag over the alternator,and secure it with rubber bands, beforesteam-cleaning the engine.

14 Charging system - check 31 If a malfunction occurs in the chargingcircuit, don’t automatically assume that thealternator is causing the problem. First checkthe following items:a) Check the drivebelt tension and condition

(see Chapter 1). Renew the drivebelt if it’sworn or deteriorated.

b) Make sure the alternator mounting andadjustment bolts are tight.

c) Inspect the alternator wiring harness andthe connectors at the alternator andvoltage regulator. They must be in goodcondition and tight.

d) Check the fuses.e) Start the engine and check the alternator

for abnormal noises (a shrieking orsquealing sound indicates a worn bearing,but could also be due to a slippingdrivebelt - see a) above).

f) Check the specific gravity of the batteryelectrolyte. If it’s low, charge the battery(doesn’t apply to maintenance-freebatteries).

g) Make sure the battery is fully-charged(one bad cell in a battery can causeovercharging by the alternator).

h) Disconnect the battery cables (negativefirst, then positive). Inspect the batteryposts and the cable clamps for corrosion.Clean them thoroughly if necessary (seeChapter 1).


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.


2 With the ignition off, connect a 12 volt testlight between the battery negative post andthe disconnected negative cable clamp. If thetest light does not come on, refit the cableand proceed to paragraph 4. If the test lightcomes on, there is a short (drain) in theelectrical system of the vehicle. The shortmust be repaired before the charging systemcan be checked. Note: Accessories which arealways on (such as the clock or the radiostation memory) must be disconnected beforeperforming this check.3 Disconnect the alternator wiring harness. Ifthe test light now goes out, the alternator isfaulty. If the light stays on, remove each fusein turn until the light goes out (this will tell youwhich component is shorting out).4 Using a voltmeter, check the batteryvoltage with the engine off. It should beapproximately 12 volts.5 Start the engine and check the batteryvoltage again. It should now be approximately14 to 15 volts.6 Turn on the headlights. The voltage shoulddrop, and then come back up, if the chargingsystem is working properly.7 If the voltage reading is more than thespecified charging voltage, renew the voltageregulator (refer to Section 16). If the voltage isless, the alternator diode(s), stator or rotormay be faulty, or the voltage regulator may bemalfunctioning.8 If there is no short-circuit causing batterydrain but the battery is constantlydischarging, then either the battery itself isdefective, the alternator drivebelt is loose (seeChapter 1), the alternator brushes are worn,dirty or disconnected (see Section 17), thevoltage regulator is malfunctioning (seeSection 16) or the diodes, stator coil or rotorcoil are defective. Repairing or renewing thediodes, stator coil or rotor coil is beyond thescope of the home mechanic. Either renew


12.11 The sensor tip should be set at 1.0 ±0.3 mm from the pulse wheel

5

the alternator complete, or take it to anautomotive electrician, who may be able tooverhaul it. Note: On models up to 1986, ablown ignition/no-charge warning light bulbwill prevent the alternator from charging. After1987, a resistor is wired in parallel with thewarning light, in order to allow current tobypass the light in the event of a broken circuit(blown warning light).

15 Alternator - removal and refitting 1



Removal1 Detach the battery negative cable.

2 Detach the electrical connectors from thealternator, noting their locations for refitting(see illustration). Note: On some models, itmay be necessary to remove the air cleanerassembly and airflow meter to gain access tothe alternator.3 Loosen the alternator adjustment and pivotbolts, and slip off the drivebelt (see Chap-ter 1).4 Remove the adjustment and pivot bolts,and separate the alternator from the engine.

Refitting5 If you are renewing the alternator, take theold one with you when purchasing a new orreconditioned unit. Make sure the new unitlooks identical to the old alternator. Look atthe terminals - they should be the same innumber, size and location as the terminals onthe old alternator. Finally, look at the identifi-cation numbers - they will be stamped into thehousing, or printed on a tag attached to thehousing. Make sure the numbers are the sameon both alternators.6 Many new alternators do not come with apulley fitted, so you may have to transfer thepulley from the old unit to the new one.7 Refitting is the reverse of removal.8 After the alternator is fitted, adjust thedrivebelt tension (see Chapter 1).9 Check the charging voltage to verify proper operation of the alternator (see Sec-tion 14).

16 Voltage regulator - renewal 11 The voltage regulator controls the chargingsystem voltage by limiting the alternatoroutput. The regulator is a sealed unit, and isn’tadjustable.2 If the voltmeter indicates that the alternatoris not charging (or if the ignition/no-chargewarning light comes on) and the alternator,battery, drivebelt tension and electricalconnections seem to be fine, have the

regulator checked by a dealer servicedepartment or electrical specialist.3 Disconnect the battery negative cable.



Bosch alternator4 The voltage regulator is mounted externallyon the alternator housing. To renew theregulator, remove the mounting screws (seeillustration) and lift it off the alternator (seeillustration). Note: Some Bosch alternatorshave an integral voltage regulator which is partof the brush assembly.5 Refitting is the reverse of removal. Note:Before refitting the regulator, check thecondition of the slip rings (see illustration).Use a torch and check for any scoring or deepwear grooves. Renew the alternator ifnecessary.

Motorola alternator6 Remove the alternator from the enginecompartment (see Section 15).7 Remove the rear cover and diode carrier,remove the voltage regulator mountingscrews (see illustration) and lift the regulatoroff the alternator body.8 Refitting is the reverse of removal.

17 Alternator brushes - check and renewal 3



16.5 Use a torch to check the slip rings forscoring or deep grooves

16.4b The regulator can be withdrawneasily on Bosch alternators. This type of

regulator is integral with the brushassembly

16.4a Remove the nuts and lift off thesmall terminal protector from the

alternator cover, then remove the nuts andthe cover

15.2 Depending on how many accessoriesthe vehicle has, sometimes it’s easier toremove the alternator from the brackets

first, and then turn it sideways to gainaccess to the connections (arrowed) on

the rear of the alternator body

Refer to the information on page 0-7 at thefront of this manual before detaching thecable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

1 Disconnect the battery negative cable.

Bosch alternator2 Remove the voltage regulator from the backof the alternator (see Section 16).3 Measure the length of the brushes (seeillustration). They should not be less than 6.0 mm. If any are worn past this point, renewthem all as a set.

4 Also check for excessively worn slip rings(see illustration 16.5).5 The brushes are retained either by setscrews or by solder. If you are not skilled atsoldering, it may be best to have an autoelectrician fit the new brushes. Note: Becareful not to apply heat to the solder joint formore than 5 seconds. If necessary, use a heatsink to capture the excess heat. This can beaccomplished by clamping a pair of needle-nose pliers next to the solder joint.6 On the screw type, hold the assembly inplace and refit the screws. Tighten themevenly, a little at a time, so the holder isn’tdistorted.7 Refit the regulator assembly to thealternator.

8 Reconnect the battery negative cable.

Motorola alternator9 Remove the alternator.10 The brushes are mounted under theregulator on the rear of the alternator (seeillustration 16.7).11 Remove the mounting screws andinsulating washers, and separate the voltageregulator and brush holder from the brush endhousing.12 Measure the length of the brushes (seeillustration 17.3). If any brush is less then 6.0 mm long, renew them all as a set.13 Make sure the brushes move smoothly inthe holder.14 Refit the brush holder/regulator. Tightenthe screws securely. Make sure the brushesaren’t earthed.15 Refitting is the reverse of removal.

18 Starting system - generalinformation and precautions

The sole function of the starting system isto turn over the engine quickly enough toallow it to start.

The starting system consists of the battery,the starter motor, the starter solenoid, theignition switch, and the wires connectingthem. The solenoid is mounted directly on thestarter motor. The starter/solenoid motorassembly is fitted on the lower part of theengine, next to the transmission bellhousing.

When the ignition key is turned to the Startposition, the starter solenoid is actuatedthrough the starter control circuit. The startersolenoid then connects the battery to thestarter, and moves the starter pinion intomesh with the flywheel ring gear. The batterysupplies the electrical energy to the startermotor, which does the actual work of crankingthe engine.

The starter motor on some manualtransmission vehicles can only be operatedwhen the clutch pedal is depressed. On avehicle equipped with automatictransmission, the starter can only be operated


17.3 Check the brush length in the normalrest position (spring uncoiled)

5

16.7 Exploded view of the Motorola alternator

when the transmission selector lever is in Parkor Neutral.

Always detach the battery negative cablebefore working on the starting system.

19 Starter motor - in-vehicle check 2

Note: Before diagnosing starter problems,make sure the battery is fully charged.1 If the starter motor does not turn at all whenthe switch is operated, make sure that thegear lever is in Neutral or Park (automatictransmission) or, where applicable, that theclutch pedal is depressed (manualtransmission).2 Make sure that the battery is charged, andthat all cables, both at the battery and startersolenoid terminals, are clean and secure.3 If the starter motor spins but the engine isnot cranking, the overrun clutch in the startermotor is slipping, and the starter motor mustbe renewed.4 If, when the switch is actuated, the startermotor does not operate at all but the solenoidclicks, then the problem lies either in thebattery, the main solenoid contacts, or thestarter motor itself (or the engine is seized).5 If the solenoid plunger cannot be heardwhen the switch is actuated, the battery isfaulty, the switch is defective, the fusible linkis burned-out (the circuit is open), or thesolenoid itself is defective.6 To check the solenoid, connect a jumperlead between the battery (+) and the ignitionswitch wire terminal (the small terminal) on thesolenoid. If the starter motor now operates,the solenoid is OK and the problem is in theignition switch, starter inhibitor switch(automatic transmission models), clutchswitch (some manual transmission models), orthe wiring.7 If the starter motor still does not operate,remove the starter/solenoid assembly fordismantling, testing and repair.8 If the starter motor cranks the engine at anabnormally-slow speed, first make sure thatthe battery is charged, and that all terminalconnections are tight. If the engine is partially-seized, or has the wrong viscosity oil in it, itwill crank slowly.9 Run the engine until normal operatingtemperature is reached, then disconnect thecoil HT lead from the distributor cap and earthit on the engine.10 Connect a voltmeter positive lead to thebattery positive post, and connect thenegative lead to the negative post.

11 Crank the engine, and take the voltmeterreadings as soon as a steady figure isindicated. Do not allow the starter motor toturn for more than 10 seconds at a time. Areading of 9 volts or more, with the startermotor turning at normal cranking speed, isnormal. If the reading is 9 volts or more butthe cranking speed is slow, the solenoidcontacts are burned, there is a badconnection, or the starter motor itself is faulty.If the reading is less than 9 volts and thecranking speed is slow, the starter motor isfaulty or the battery is responsible (defectiveor discharged).

20 Starter motor - removal and refitting 1

Note: If the starter motor is defective, it shouldbe renewed, or taken to an auto electricalspecialist for repair. Overhaul of the startermotor is unlikely to be a practical propositionfor the home mechanic, even if spare parts areavailable. However, the solenoid can berenewed separately (see Section 21).

RemovalCaution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code

before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Detach the battery negative cable.2 Raise the vehicle and support it securely onaxle stands.3 Clearly label the wires from the terminals on

the starter motor and solenoid, thendisconnect them. Note: On some models, itmay be necessary to remove the air cleaner(see Chapter 4), coolant expansion tank (seeChapter 3) and the heater hoses to gainaccess to the top of the starter. Carefully labelany hoses or components that need to beremoved from the engine compartment, toavoid confusion when reassembling.4 Unscrew the mounting bolts and detach thestarter (see illustrations).


21 Starter solenoid - removal and refitting 1

RemovalCaution: If the radio in yourvehicle is equipped with an anti-theft system, make sure youhave the correct activation code

before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable.2 Remove the starter motor (see Section 20).3 Disconnect the cable from the solenoid tothe starter motor terminal.4 Remove the screws which secure thesolenoid to the starter motor.5 Detach the solenoid from the starter body.6 Remove the plunger and plunger spring.



20.4b Withdrawing the starter motor fromthe M40 engine

20.4a Working under the vehicle, removethe starter lower mounting bolt and nut

(arrowed)

6

Chapter 6 Engine management and emission control systems

Catalytic converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Electronic Control Unit (ECU) - removal and refitting . . . . . . . . . . . . 3Evaporative emissions control (EVAP) system . . . . . . . . . . . . . . . . . 6Evaporative emissions control system inspection . . . See Chapter 1General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Information sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Motronic engine management system self-diagnosis -

general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Positive crankcase ventilation (PCV) system . . . . . . . . . . . . . . . . . . 5

6•1







Contents


To prevent pollution of the atmospherefrom incomplete combustion or evaporationof the fuel, and to maintain good driveabilityand fuel economy, a number of emissioncontrol systems are used on these vehicles.Not all of these systems are fitted to allmodels, but they include the following:Catalytic converterEvaporative emission control (EVAP) systemPositive crankcase ventilation (PCV) systemElectronic engine managementThe Sections in this Chapter include

general descriptions and checkingprocedures within the scope of the homemechanic, as well as component renewalprocedures (when possible) for each of thesystems listed above.

Before assuming that an emissions controlsystem is malfunctioning, check the fuel andignition systems carefully. The diagnosis ofsome emission control devices requiresspecialised tools, equipment and training. Ifchecking and servicing become too difficult,or if a procedure is beyond your ability,consult a dealer service department or otherspecialist.

This doesn’t mean, however, that emissioncontrol systems are particularly difficult tomaintain and repair. You can quickly andeasily perform many checks, and do most ofthe regular maintenance at home withcommon tune-up and hand tools.

Pay close attention to any specialprecautions outlined in this Chapter. It shouldbe noted that the illustrations of the varioussystems may not exactly match the systemfitted on your vehicle because of changes made by the manufacturer duringproduction.

2 Motronic engine managementsystem self-diagnosis -general information

The Motronic engine management systemcontrol unit (computer) has a built-in self-diagnosis system, which detects malfunctionsin the system sensors and stores them asfault codes in its memory. It is not possiblewithout dedicated test equipment to extractthese fault codes from the control unit.However, the procedures given in Chapters 4and 5 may be used to check individualcomponents and sensors of the Motronicsystem. If this fails to pinpoint a fault, then thevehicle should be taken to a BMW dealer, whowill have the necessary diagnostic equipment to call up the fault codes from thecontrol unit. You will then have the option to repair the fault yourself, oralternatively have the fault repaired by theBMW dealer.

3 Electronic control unit (ECU)- removal and refitting 2

Removal1 The Electronic Control Unit (ECU) is locatedeither inside the passenger compartmentunder the right-hand side of the facia panel on3-Series models, or in the enginecompartment on the right-hand side on 5-Series models (see Chapter 4).2 Disconnect the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.3 First remove the access cover on modelswith the ECU on the right-hand side of theengine compartment (see Chapter 4).4 If the ECU is located inside the vehicle,remove the access cover on the right-hand side.5 Unplug the electrical connectors from theECU.6 Remove the retaining bolts from the ECUbracket.7 Carefully remove the ECU. Note: Avoid staticelectricity damage to the ECU by wearing rubbergloves, and do not touch the connector pins.

Refitting8 Refitting is a reversal of removal.

The most frequent cause ofemission system problems issimply a leaking vacuum hoseor loose wire, so always

check the hose and wiring connectionsfirst.

4 Information sensors 2Note: Refer to Chapters 4 and 5 for additionalinformation on the location and diagnosis ofthe information sensors that are not covered inthis Section.

Coolant temperature sensorGeneral description1 The coolant temperature sensor (seeillustration) is a thermistor (a resistor whichvaries its resistance value in accordance withtemperature changes). The change in theresistance value regulates the amount ofvoltage that can pass through the sensor. Atlow temperatures, the sensor’s resistance ishigh. As the sensor temperature increases, itsresistance will decrease. Any failure in thissensor circuit will in most cases be due to aloose or shorted-out wire; if no wiringproblems are evident, check the sensor asdescribed below.

Check2 To check the sensor, first check itsresistance (see illustration) when it iscompletely cold (typically 2100 to 2900 ohms).Next, start the engine and warm it up until itreaches operating temperature. The resistanceshould be lower (typically 270 to 400 ohms).Note: If restricted access to the coolanttemperature sensor makes it difficult to attachelectrical probes to the terminals, remove thesensor as described below, and perform thetests in a container of heated water to simulatethe conditions.


Renewal3 To remove the sensor, depress the springlock, unplug the electrical connector, thencarefully unscrew the sensor. Be prepared forsome coolant spillage; to reduce this, havethe new sensor ready for fitting as quickly aspossible.

Caution: Handle the coolantsensor with care. Damage to thissensor will affect the operation ofthe entire fuel injection system.

Note: It may be necessary to drain a smallamount of coolant from the radiator beforeremoving the sensor.4 Before the sensor is fitted, ensure itsthreads are clean, and apply a little sealant tothem.5 Refitting is the reverse of removal.

Oxygen sensorGeneral descriptionNote: Oxygen sensors are normally only fittedto those vehicles equipped with a catalyticconverter. Most oxygen sensors are located inthe exhaust pipe, downstream from theexhaust manifold. On 535 models, the oxygensensor is mounted in the catalytic converter.The sensor’s electrical connector is locatednear the bulkhead (left side) for easy access.6 The oxygen sensor, which is located in theexhaust system (see illustration), monitorsthe oxygen content of the exhaust gas. Theoxygen content in the exhaust reacts with theoxygen sensor, to produce a voltage outputwhich varies from 0.1 volts (high oxygen, leanmixture) to 0.9 volts (low oxygen, richmixture). The ECU constantly monitors thisvariable voltage output to determine the ratioof oxygen to fuel in the mixture. The ECUalters the air/fuel mixture ratio by controllingthe pulse width (open time) of the fuelinjectors. A mixture ratio of 14.7 parts air to 1part fuel is the ideal mixture ratio forminimising exhaust emissions, thus allowingthe catalytic converter to operate at maximumefficiency. It is this ratio of 14.7 to 1 which theECU and the oxygen sensor attempt tomaintain at all times.7 The oxygen sensor produces no voltagewhen it is below its normal operatingtemperature of about 320º C. During this initialperiod before warm-up, the ECU operates in“open-loop” mode (ie without the informationfrom the sensor).8 If the engine reaches normal operatingtemperature and/or has been running for twoor more minutes, and if the oxygen sensor isproducing a steady signal voltage below

0.45 volts at 1500 rpm or greater, the ECUfault code memory will be activated.9 When there is a problem with the oxygensensor or its circuit, the ECU operates in the“open-loop” mode - that is, it controls fueldelivery in accordance with a programmeddefault value instead of with feedbackinformation from the oxygen sensor.10 The proper operation of the oxygensensor depends on four conditions:a) Electrical - The low voltages generated by

the sensor depend upon good, cleanconnections, which should be checkedwhenever a malfunction of the sensor issuspected or indicated.

b) Outside air supply - The sensor isdesigned to allow air circulation to theinternal portion of the sensor. Wheneverthe sensor is disturbed, make sure the airpassages are not restricted.

c) Proper operating temperature - The ECUwill not react to the sensor signal until thesensor reaches approximately 320º C.This factor must be taken intoconsideration when evaluating theperformance of the sensor.

d) Unleaded fuel - The use of unleaded fuelis essential for proper operation of thesensor. Make sure the fuel you are usingis of this type.

11 In addition to observing the aboveconditions, special care must be takenwhenever the sensor is serviced.a) The oxygen sensor has a permanently-

attached pigtail and electrical connector,which should not be removed from thesensor. Damage or removal of the pigtailor electrical connector can adverselyaffect operation of the sensor.

b) Grease, dirt and other contaminantsshould be kept away from the electricalconnector and the louvered end of thesensor.

c) Do not use cleaning solvents of any kindon the oxygen sensor.

d) Do not drop or roughly handle the sensor.e) The silicone boot must be fitted in the

correct position, to prevent the boot frombeing melted and to allow the sensor tooperate properly.

6•2 Engine management and emission control systems

4.6 The oxygen sensor (arrowed) is usuallylocated in the exhaust pipe, downstream

from the exhaust manifold

4.2 Check the resistance of the coolanttemperature sensor at different

temperatures

4.1 The coolant temperature sensor(arrowed) is usually located next to thetemperature sender unit, near the fuel

pressure regulator

Check12 Warm up the engine, and let it run at idle.Disconnect the oxygen sensor electricalconnector, and connect the positive probe ofa voltmeter to the oxygen sensor outputconnector terminal (refer to the followingtable) and the negative probe to earth (seeillustrations).Note: Most oxygen sensor electricalconnectors are located at the rear of theengine, near the bulkhead. Look for a largerubber boot attached to a thick wire harness.On early 535i models, the connector for theoxygen sensor heater circuit is under thevehicle. Look for a small protective cover.These models should have the updatedoxygen sensor fitted, to make access similarto other models. Consult your dealer servicedepartment for additional information.13 Increase and then decrease the enginespeed, and monitor the voltage.14 When the speed is increased, the voltageshould increase to 0.5 to 1.0 volts. When thespeed is decreased, the voltage should fall toabout 0 to 0.4 volts.15 Also where applicable, inspect the oxygensensor heater (models with multi-wiresensors). With the ignition on, disconnect theoxygen sensor electrical connector, andconnect a voltmeter across the terminalsdesignated in the chart (see below). Thereshould be battery voltage (approximately 12 volts).16 If the reading is not correct, check theoxygen sensor heater relay (see Chapter 12).If the information is not available, check theowner’s handbook for the exact location ofthe oxygen sensor heater relay. The relayshould receive battery voltage.17 If the oxygen sensor fails any of thesetests, renew it.

RenewalNote: Because it is fitted in the exhaustmanifold, converter or pipe, which contractswhen cool, the oxygen sensor may be verydifficult to loosen when the engine is cold.Rather than risk damage to the sensor

(assuming you are planning to re-use it inanother manifold or pipe), start and run theengine for a minute or two, then switch it off.Be careful not to burn yourself during thefollowing procedure.18 Disconnect the battery negative cable.


before disconnecting the battery. Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable.Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.19 Raise and support the vehicle.20 Disconnect the electrical connector fromthe sensor.21 Carefully unscrew the sensor.

Caution: Excessive force maydamage the threads.

22 A high-temperature anti-seize compoundmust be used on the threads of the sensor, tofacilitate future removal. The threads of newsensors will already be coated with thiscompound, but if an old sensor is removedand refitted, recoat the threads.

23 Refit the sensor and tighten it securely.24 Reconnect the electrical connector of thepigtail lead to the main engine wiring harness.25 Lower the vehicle, and reconnect thebattery.Oxygen Sensor Heated power sensor type output signal supply (12V)

Unheated(single-wire) black wire (+) Not applicable

Heated terminal 1 (+) terminals (three-wire) 3 (+) and 2 (-)

Heated terminal 2 (+) terminals (four-wire) 4 (+) and 3 (-)

Throttle Position Sensor (TPS)General description26 The Throttle Position Sensor (TPS) islocated on the end of the throttle shaft on thethrottle body. By monitoring the outputvoltage from the TPS, the ECU can determinefuel delivery based on throttle valve angle(driver demand). In this system, the TPS actsas a switch rather than a potentiometer. Oneset of throttle valve switch contacts is closed(continuity) only at idle. A second set ofcontacts closes as the engine approachesfull-throttle. Both sets of contacts are open(no continuity) between these positions. Abroken or loose TPS can cause intermittentbursts of fuel from the injector and anunstable idle, because the ECU thinks thethrottle is moving.27 All models (except for early 535i modelswith automatic transmission) combine the idleand full-throttle switch; a separate idleposition switch indicates the closed-throttleposition, while the TPS is used for the full-throttle position. On 535i models withautomatic transmission, the TPS is connecteddirectly to the automatic transmission controlunit. With the throttle fully open, thetransmission control unit sends the full-throttle signal to the Motronic control unit.

All models except early 535i withautomatic transmissionCheck28 Remove the electrical connector from theTPS, and connect an ohmmeter to terminals 2and 18 (see illustrations). Open the throttle

Engine management and emission control systems 6•3

4.12b These oxygen sensor terminaldesignations are for the harness side only.

Use the corresponding terminals on thesensor side for the testing procedures

(there are three different four-wire oxygensensor connectors available - don’t get

them mixed up)

4.12a The oxygen sensor, once it iswarmed up (320º C), puts out a very small

voltage signal. To verify it is working,check for voltage with a digital voltmeter(the voltage signals usually range from

0.1 to 1.0 volt)

4.28b First check for continuity betweenterminals 2 and 18 with the throttle closed

(later Motronic system shown) . . .

4.28a The TPS on L-Jetronic systems islocated under the intake manifold

(terminals arrowed)

6

slightly by hand. Release the throttle slowlyuntil it reaches 0.2 to 0.6 mm from the throttlestop. There should be continuity.29 Check the resistance between terminals 3and 18 as the throttle is opened. There shouldbe continuity when the throttle switch is within8 to 12 degrees of fully-open. If the readingsare incorrect, adjust the TPS.30 If all the resistance readings are correctand the TPS is properly adjusted, check forpower (5 volts) at the sensor, and if necessarytrace any wiring circuit problems between thesensor and ECU (see Chapter 12).Adjustment31 If the adjustment is not as specified(paragraphs 28 to 30), loosen the screws onthe TPS, and rotate the sensor into the correctadjustment. Follow the procedure forchecking the TPS given above, and tightenthe screws when the setting is correct.32 Recheck the TPS once more; if thereadings are correct, reconnect the TPSharness connector.

Early 535i models with automatictransmissionCheck33 First test the continuity of the TPS. Followparagraphs 28 to 30 and check for continuity.34 Next, test the idle position switch (seeillustration). Unplug the electrical connectorin the idle position switch harness, and

connect an ohmmeter to terminals 1 and 2.There should be continuity. Open the throttleslightly, and measure the resistance. Thereshould now be no continuity.35 Check for the correct voltage signals fromthe TPS, with the throttle closed and theignition on. Probe the back of the TPSconnector with a voltmeter, and check forvoltage at terminal 3 (black wire) and earth.There should be 5 volts present. Also, probeterminal 3 (black wire) and terminal 1 (brownwire). There should be 5 volts present herealso.36 Check for voltage at terminal 2 (yellowwire) and terminal 1 (brown wire), and slowlyopen the throttle. The voltage should increasesteadily from 0.7 volts (throttle closed) to 4.8 volts (throttle fully-open).Adjustment37 First measure the stabilised voltage. Withthe ignition on and the throttle closed,measure the voltage between terminal 3(black wire) and terminal 1 (brown wire). Itshould be about 5 volts.38 Next, loosen the sensor mounting screws,and connect the voltmeter to terminal 2(yellow wire) and terminal 3 (black wire). Withthe throttle fully open, rotate the switch untilthere is 0.20 to 0.24 volts less than thestabilised voltage. Note: You will need adigital voltmeter to measure these smallchanges in voltage.39 Recheck the TPS once more; if thereadings are correct, reconnect the TPSelectrical connector. It is a good idea to lockthe TPS screws with paint or thread-lockingcompound.

Airflow meter

General description40 The airflow meter is located on the airintake duct. The airflow meter measures theamount of air entering the engine. The ECUuses this information to control fuel delivery. Alarge volume of air indicates acceleration,while a small volume of air indicatesdeceleration or idle. Refer to Chapter 4 for allthe diagnostic checks and renewalprocedures for the airflow meter.

Ignition timing sensors41 Ignition timing is electronically-controlledon Motronic systems, and is not adjustable.During starting, a crankshaft position sensorrelays the crankshaft position to the ECU, andan initial baseline ignition point is determined.Once the engine is running, the ignition pointis continually changing based on the variousinput signals to the ECU. Engine speed issignalled by a speed sensor. Early Motronicsystems have the reference sensor and thespeed sensor mounted on the bellhousingover the flywheel. Later Motronic systemshave a single sensor (pulse sensor) mountedover the crankshaft pulley. This sensorfunctions as a speed sensor as well as aposition sensor. Refer to Chapter 5 for moreinformation. Note: Some models areequipped with a TDC sensor mounted on thefront of the engine. This sensor is strictly forthe BMW service test unit, and it is not part ofthe Motronic ignition system.

5 Positive crankcaseventilation (PCV) system

1 The Positive Crankcase Ventilation (PCV)system (see illustration) reduceshydrocarbon emissions by scavengingcrankcase vapours. It does this by circulatingblow-by gases and then re-routing them tothe intake manifold by way of the air cleaner.2 This PCV system is a sealed system. Thecrankcase blow-by vapours are routeddirectly to the air cleaner or air collector withcrankcase pressure behind them. The vapouris not purged with fresh air on most models or


5.2 PCV hose being removed from thevalve cover

5.1 Diagram of the PCV system on theM20 engine (others similar)

4.34 Idle position switch and TPS on early535i models with automatic transmission

4.28c . . . then check for continuitybetween terminals 3 and 18 as the throttle

is opened

filtered with a flame trap like mostconventional systems. There are noconventional PCV valves fitted on thesesystems - just a hose (see illustration).3 The main components of the PCV systemare the hoses that connect the valve cover tothe throttle body or air cleaner. If abnormaloperating conditions (such as piston ringproblems) arise, the system is designed toallow excessive amounts of blow-by gases toflow back through the crankcase vent tubeinto the intake system, to be consumed bynormal combustion. Note: Since thesemodels don’t use a filtering element, it’s agood idea to check the PCV systempassageways for clogging from sludge andcombustion residue (see illustration).

6 Evaporative emissionscontrol (EVAP) system 2

General descriptionNote: This system is normally only fitted tothose vehicles equipped with a catalyticconverter.1 When the engine isn’t running, the fuel in thefuel tank evaporates to some extent, creatingfuel vapour. The evaporative emissions controlsystem (see illustration) stores these fuelvapours in a charcoal canister. When theengine is cruising, the purge control valve isopened slightly, and a small amount of fuelvapour is drawn into the intake manifold andburned. When the engine is starting cold oridling, the purge valve prevents any vapoursfrom entering the intake manifold and causingexcessively-rich fuel mixture.2 Two types of purge valve are used;electrically-operated or vacuum-operated. Tofind out which type is on your vehicle, followthe hose from the charcoal canister until youlocate the purge valve. Some are located onthe intake manifold, and others near thecharcoal canister. Look for either an electricalconnector, or vacuum lines, to the purgevalve.

3 A faulty EVAP system will only affect enginedriveability when the engine is warm. TheEVAP system is not usually the cause ofdifficult cold starting or any other cold-runningproblems.

CheckVacuum-operated purge valve4 Remove the vacuum lines from the purgevalve, and blow into the larger valve port. Itshould be closed, and not pass any air. Note:Some models have a thermo-vacuum valvethat delays canister purging until the coolanttemperature reaches approximately 46º C.Check this valve to make sure that vacuum iscontrolled at the proper temperatures. Thevalve is usually located in the intake manifold,near the thermo-time switch and the coolanttemperature sensor.5 Disconnect the small vacuum hose from thepurge valve, and apply vacuum with a hand-held vacuum pump. The purge valve shouldbe open, and air should be able to passthrough.

6 If the test results are unsatisfactory, renewthe purge valve.

Electrically-operated purge valve7 Disconnect any lines from the purge valve,and (without disconnecting the electricalconnector) place it in a convenient spot fortesting.8 Check that the valve makes a “click” soundas the ignition is switched on (seeillustration).9 If the valve does not “click”, disconnect thevalve connector, and check for power to thevalve using a test light or a voltmeter (seeillustration).10 If battery voltage is present, but the valvedoes not work, renew it. If there is no voltagepresent, check the Motronic control unit andthe wiring.

Canister11 Mark all the hoses for position, thendetach them from the canister.12 Slide the canister out of its mounting clip.

Engine management and emission control systems 6•5

6.1 Diagram of the EVAP system on the M10 engine (others similar)

6.9 Check for battery voltage at theelectrical connector to the purge valve

6.8 When the ignition is switched on, thereshould be a distinct “click” from the purge

valve

6

5.3 It’s a good idea to check for excessresidue from the crankcase vapours

circulating in the hoses and ports - thiscan eventually clog the system, and cause

a pressure increase in the engine block

On some models, it will be necessary torelease the retaining clip (see illustration).13 Visually examine the canister for leakageor damage.14 Renew the canister if you find evidence ofdamage or leakage.

7 Catalytic converter 1General description1 To reduce emissions of unburnthydrocarbons (HC), carbon monoxide (CO)and oxides of nitrogen (NOx), the latervehicles covered by this manual are equippedwith a catalytic converter (see illustration).The converter contains a ceramic honeycombcoated with precious metals, which speed upthe reaction between the pollutants listedpreviously and the oxygen in the exhaust gas.The pollutants are oxidised to produce water(H2O), nitrogen and carbon dioxide (CO2).

Check2 Visually examine the converter(s) for cracksor damage. Make sure all nuts and bolts aretight.3 Inspect the insulation cover (if applicable)welded onto the converter - it should not beloose.

Caution: If an insulation cover isdented so that it touches theconverter housing inside,excessive heat may betransferred to the floor.

4 Start the engine and run it at idle speed.5 Check for exhaust gas leakage from theconverter flanges. Check the body of eachconverter for holes.

Component renewal6 See Chapter 4 for removal and refittingprocedures.

Precautions7 The catalytic converter is a reliable andsimple device, which needs no maintenancein itself, but there are some facts of which anowner should be aware, if the converter is tofunction properly for its full service life.(a) DO NOT use leaded (eg UK “4-star”)

petrol in a car equipped with a catalyticconverter - the lead will coat the preciousmetals, reducing their convertingefficiency, and will eventually destroy theconverter.

(b) Always keep the ignition and fuel systemswell-maintained in accordance with themanufacturer’s schedule, as given inChapter 1. In particular, ensure that the aircleaner filter element, the fuel filter (wherefitted) and the spark plugs are renewed atthe correct interval. If the intake air/fuelmixture is allowed to become too rich dueto neglect, unburned fuel will enter thecatalytic converter, overheating theelement and eventually destroying theconverter.

(c) If the engine develops a misfire, do notdrive the car at all (or at least as little aspossible) until the fault is cured - themisfire will allow unburned fuel to enterthe converter, which will result in itsoverheating, as noted above.

(d) DO NOT push- or tow-start the car - thiswill soak the catalytic converter inunburned fuel, causing it to overheatwhen the engine does start - see (b) or (c)above.

(e) DO NOT switch off the ignition at highengine speeds - ie do not “blip” thethrottle immediately before switching off

the engine. If the ignition is switched offat anything above idle speed, unburnedfuel will enter the (very hot) catalyticconverter, with the possible risk of itsigniting on the element and damaging theconverter.

(f) DO NOT use fuel or engine oil additives -these may contain substances harmful tothe catalytic converter.

(g) DO NOT continue to use the car if theengine burns oil to the extent of leaving avisible trail of blue smoke - the unburnedcarbon deposits will clog the converterpassages, and reduce its efficiency; insevere cases, the element will overheat.

(h) Remember that the catalytic converteroperates at very high temperatures -hence the heat shields on the car’sunderbody - and the casing will becomehot enough to ignite combustiblematerials which brush against it. DO NOT,therefore, park the car in dryundergrowth, or over long grass or pilesof dead leaves.

(i) Remember that the catalytic converter isFRAGILE - do not strike it with toolsduring servicing work, and take great carewhen working on the exhaust system.Ensure that the converter is well clear ofany jacks or other lifting gear used to raisethe car, and do not drive the car overrough ground, road humps, etc, in such away as to “ground” the exhaust system.

(j) In some cases, particularly when the caris new and/or is used for stop/startdriving, a sulphurous smell (like that ofrotten eggs) may be noticed from theexhaust. This is common to manycatalytic converter-equipped cars, andseems to be due to the small amount ofsulphur found in some petrols reactingwith hydrogen in the exhaust, to producehydrogen sulphide (H2S) gas; while thisgas is toxic, it is not produced in sufficientamounts to be a problem. Once the carhas covered a few thousand miles, theproblem should disappear - in themeanwhile, a change of driving style, or ofthe brand of petrol used, may effect asolution.

(k) The catalytic converter, used on a well-maintained and well-driven car, shouldlast for 50 000 to 100 000 miles - fromthis point on, the CO level should becarefully checked regularly, to ensure thatthe converter is still operating efficiently. Ifthe converter is no longer effective, itmust be renewed.


7.1 Typical catalytic converter (M10engine type shown, others similar)

6.12 EVAP system charcoal canisterviewed from under the vehicle (316i model)

9

GeneralBrake fluid type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1

Disc brakesMinimum brake pad thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Brake disc minimum permissible thickness (wear limit)*

Front3-Series

Solid discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 mmVentilated discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.0 mm

5-SeriesSolid discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 mmVentilated discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.0 mm

Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 mmBrake disc minimum thickness after machining

Front3-Series

Solid discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 mmVentilated discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.4 mm

5-SeriesSolid discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4 mmVentilated discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20.4 mm

Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 mmParallelism (difference between any two measurements) . . . . . . . . . . . 0.02 mmMaximum disc run-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 mm* Refer to marks cast into the disc (they supersede information printed here)

Brake pedal adjustmentsBrake pedal/servo pushrod adjustment (A) (3-Series) . . . . . . . . . . . . . . 125 mmBrake pedal height (pedal-to-bulkhead distance)

3-SeriesLeft-hand-drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 mmRight-hand-drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 mm

5-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 mmStop-light switch adjustment (dimension A - see text) . . . . . . . . . . . . . . 5.0 mm to 6.0 mm

HandbrakeHandbrake shoe lining minimum thickness . . . . . . . . . . . . . . . . . . . . . . 1.5 mmHandbrake lever travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 to 8 clicks

Chapter 9 Braking system

Anti-lock brake system (ABS) - general information . . . . . . . . . . . . . 2Brake check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Brake disc - inspection, removal and refitting . . . . . . . . . . . . . . . . . 5Brake fluid level check . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Brake hoses and lines - inspection and renewal . . . . . . . . . . . . . . . . 15Brake hydraulic system - bleeding . . . . . . . . . . . . . . . . . . . . . . . . . . 16Brake pedal - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Brake vacuum servo - check, removal and refitting . . . . . . . . . . . . . 8Disc brake caliper - removal, overhaul and refitting . . . . . . . . . . . . . 4

Disc brake pads - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Drum brake shoes - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Handbrake assembly - check, removal and refitting . . . . . . . . . . . . 12Handbrake - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Handbrake cable(s) - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Hydraulic brake servo - description, removal and refitting . . . . . . . . 9Master cylinder - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 7Stop-light switch - check and adjustment . . . . . . . . . . . . . . . . . . . . 14

9•1







Specifications

Contents

Torque wrench settings NmFront disc brake caliper

Caliper guide (mounting) bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 35Caliper bracket-to-strut housing bolts

3-Series, E30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1235-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1235-Series, E34 (“new-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Rear disc brake caliperCaliper guide (mounting) bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 35Carrier-to-trailing arm bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Brake hose-to-caliper fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 to 17Master cylinder-to-brake servo nuts

3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 to 29

Brake servo mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 24Hydraulic line-to-hydraulic brake servo threaded fittings - 5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Wheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1

9•2 Braking system


All 3-Series models, and 5-Series E28 (“old-shape”) models, are equipped with front discbrakes and either rear drum or rear discbrakes. 5-Series E34 (“new-shape”) modelshave disc brakes front and rear. Front andrear brakes are self-adjusting on all models.Some later models are equipped with an Anti-lock Braking System (ABS); this is describedin Section 2.

Hydraulic systemThe hydraulic system consists of two

separate circuits. The master cylinder hasseparate reservoirs for the two circuits; in theevent of a leak or failure in one hydrauliccircuit, the other circuit will remain operative.

Brake servoThe vacuum brake servo, utilising engine

manifold vacuum and atmospheric pressureto provide assistance to the hydraulicallyoperated brakes, is mounted on the bulkheadin the engine compartment.

A hydraulic brake servo system is used on5-Series E28 models. This system useshydraulic pressure from the power steeringpump to assist braking.

HandbrakeThe handbrake operates the rear brakes,

and is cable-operated via a lever mounted inthe centre console. The handbrake assemblyon rear drum brake models is part of the reardrum brake assembly, and is self-adjusting.On rear disc brake models, the handbrakeuses a pair of brake shoes located inside thecentre portion of the rear brake disc, and ismanually-adjusted.

Brake pad wear warning systemThe brake pad wear warning system is

linked to a red warning light in the instrument

cluster, which comes on when the brake padshave worn down to the point at which theyrequire renewal. DO NOT ignore this reminder.If you don’t renew the pads shortly after thebrake pad wear warning light comes on, thebrake discs will be damaged.

On some models, the brake pad wearwarning system also includes an earlywarning light that comes on only when thebrake pedal is depressed, letting you know inadvance that the pads need to be renewed.

The wear sensor is attached to the brakepads. The sensor is located at the left frontwheel; on some models, there is anothersensor at the right rear wheel. The wearsensor is part of a closed circuit. Once thepads wear down to the point at which they’reflush with the sensor, the disc grinds away theside of the sensor facing the disc. Thus, thewire inside the sensor is broken, and the redlight on the instrument panel comes on.

Always check the sensor(s) when renewingthe pads. If you change the pads before thewarning light comes on, the sensor(s) may stillbe good; once the light has come on, renewthe sensor.

ServiceAfter completing any operation involving

dismantling of any part of the brake system,always test drive the vehicle to check forproper braking performance before resumingnormal driving. When testing the brakes, try toselect a clean, dry, road with no camber (ie asflat as possible) and with no other traffic.Conditions other than these can lead toinaccurate test results.

Test the brakes at various speeds with bothlight and heavy pedal pressure. The vehicleshould stop evenly, without pulling to one sideor the other. Avoid locking the brakes,because this slides the tyres and diminishesbraking efficiency and control of the vehicle.

Tyres, vehicle load and wheel alignment arefactors which also affect brakingperformance.

2 Anti-lock Braking system(ABS) - general information

The Anti-lock Braking System is designedto maintain vehicle control, directional stabilityand optimum deceleration under severebraking conditions on most road surfaces. Itdoes so by monitoring the rotational speed ofeach wheel and controlling the brake linepressure to each wheel during braking. Thisprevents the wheels from locking up.

The ABS system has three maincomponents - the wheel speed sensors, theelectronic control unit, and the hydrauliccontrol unit. The sensors - one at each wheelsince 1985, but at both front wheels and oneat the rear differential on earlier models - senda variable voltage signal to the control unit,which monitors these signals, compares themto its program information, and determineswhether a wheel is about to lock up. When awheel is about to lock up, the control unitsignals the hydraulic unit to reduce hydraulicpressure (or not increase it further) at thatwheel’s brake caliper. Pressure modulation ishandled by electrically-operated solenoidvalves.

If a problem develops within the system, an“ABS” warning light will glow on thedashboard. Sometimes, a visual inspection ofthe ABS system can help you locate theproblem. Carefully inspect the ABS wiringharness. Pay particularly close attention to theharness and connections near each wheel.Look for signs of chafing and other damagecaused by incorrectly-routed wires. If a wheelsensor harness is damaged, the sensorshould be renewed (the harness and sensorare integral).

Warning: DO NOT try to repair anABS wiring harness. The ABSsystem is sensitive to even the

smallest changes in resistance. Repairingthe harness could alter resistance values

and cause the system to malfunction. Ifthe ABS wiring harness is damaged in anyway, it must be renewed.

Caution: Make sure the ignition isturned off before unplugging orre-making any electricalconnections.

Diagnosis and repairIf the dashboard warning light comes on

and stays on while the vehicle is in operation,the ABS system requires attention. Althoughspecial electronic ABS diagnostic testingtools are necessary to properly diagnose thesystem, you can perform a few preliminarychecks before taking the vehicle to a dealerservice department.a) Check the brake fluid level in the

reservoir.b) Verify that the electronic control unit

connectors are securely connected.c) Check the electrical connectors at the

hydraulic control unit.d) Check the fuses.e) Follow the wiring harness to each front

and rear wheel, and verify that allconnections are secure and that thewiring is undamaged.

If the above preliminary checks do notrectify the problem, the vehicle should be

diagnosed by a dealer service department.Due to the complex nature of this system, allactual repair work must be done by a dealerservice department.

3 Disc brake pads - renewal 2Warning: Disc brake pads mustbe renewed on both front wheelsor both rear wheels at the sametime - NEVER renew the pads on

only one wheel. Also, the dust created bythe brake system may contain asbestos,which is harmful to your health. Neverblow it out with compressed air, and don’tinhale any of it. An approved filtering maskshould be worn when working on thebrakes. Do not, under any circumstances,use petroleum-based solvents to cleanbrake parts. Use brake system cleaneronly! When servicing the disc brakes, useonly original-equipment or high-qualitybrand-name pads.

Warning: Brake fluid ispoisonous. It is also an effectivepaint stripper. Refer to thewarning at the start of Section 16.

Note: This procedure applies to both the frontand rear disc brakes.1 Remove the cap(s) from the brake fluidreservoir, and syphon off about two-thirds ofthe fluid from the reservoir. Failing to do this

could result in the reservoir overflowing whenthe caliper pistons are pressed back into theirbores.2 Loosen the wheel bolts, raise the front orrear of the vehicle and support it securely onaxle stands.3 Remove the front or rear wheels, asapplicable. Work on one brake assembly at atime, using the assembled brake for referenceif necessary.4 Inspect the brake disc carefully as outlinedin Section 5. If machining is necessary, followthe information in that Section to remove thedisc, at which time the pads can be removedfrom the calipers as well.5 Follow the accompanying photos,beginning with illustration 3.5a, for the padremoval procedure. Be sure to stay in order,and read the caption under each illustration.Note 1: Different types of front calipers areused on 3 and 5-Series models. Illustrations3.5a to 3.5e are for the front calipers on 3-Series models. Illustrations 3.5f to 3.5m arefor the front calipers on 5-Series models.There’s no photo sequence for rear calipers;although slightly different in size, they’reidentical in design to the front brake calipersused on 5-Series models. Note 2: Somemodels may have different numbers and typesof anti-squeal shims and other hardware thanwhat is shown in this Chapter. It’s best to notehow the hardware is fitted on the vehiclebefore dismantling, so you can duplicate it onreassembly.

Braking system 9•3

3.5c Hold the guide pins while looseningthe caliper mounting bolts (3-Series)

3.5b Unplug the electrical connector forthe brake pad wear sensor (3-Series)

3.5a On 3-Series models, unscrew thecaliper mounting bolts (left arrows); rightarrows point to the caliper bracket bolts,which should only be removed if you’re

removing the brake disc

3.5f On 5-Series models, unplug theelectrical connector for the brake pad

wear sensor

3.5e Remove the outer brake pad (3-Series) - to fit the new pads, reverse the

removal procedure

3.5d Remove the caliper, brake pad wearsensor and inner pad all at the same time(3-Series), then refit the inner pad on thepiston and press the piston fully into the

bore with a C-clamp

9

6 Be sure to inspect the wear sensor(s) (leftfront wheel only, or left front and right rearwheel). If they’re OK, transfer them from theold pads to the new ones; if they’re worn byabrasion, fit new sensors on the new pads.7 To fit the new pads, reverse the removalprocedure. When refitting the caliper, be sureto tighten the mounting bolts to the torquelisted in this Chapter’s Specifications.

Warning: Check and if necessaryrenew the mounting bolts on 3-Series models whenever they areremoved. If in doubt, use newbolts.

8 After the job is completed, firmly depressthe brake pedal a few times, to bring the padsinto contact with the discs. The pedal should

be at normal height above the floor, and firm.Check the level of the brake fluid, addingsome if necessary. Check carefully for leaks,and check the operation of the brakes beforereturning the vehicle to normal service.9 Avoid heavy braking as far as possible forthe first hundred miles or so until the newpads have bedded in.

4 Disc brake caliper - removal,overhaul and refitting 4

Warning: Dust created by thebrake system may containasbestos, which is harmful toyour health. Never blow it out

with compressed air, and don’t inhale anyof it. An approved filtering mask should beworn when working on the brakes. Do not,under any circumstances, use petroleum-based solvents to clean brake parts. Usebrake system cleaner only!


Note: If an overhaul is indicated (usuallybecause of fluid leakage), explore all optionsbefore beginning the job. Overhauled calipersmay be available on an exchange basis, whichmakes this job quite easy. If you decide tooverhaul the calipers, make sure that an

overhaul kit is available before proceeding.Always overhaul the calipers in pairs - neveroverhaul just one of them.

Removal1 Loosen the wheel bolts, raise the front orrear of the vehicle, and place it securely onaxle stands. Remove the wheel.2 If you’re just removing the caliper foraccess to other components, it isn’tnecessary to detach the brake line. If you’reremoving the caliper for overhaul, disconnectthe brake line from the caliper, for preferenceusing a split ring (“brake”) spanner to protectthe fitting. Plug the line, to keep contaminantsout of the brake system and to prevent losingbrake fluid unnecessarily.3 Refer to Section 3 for the front or rearcaliper removal procedure - it’s part of thebrake pad renewal procedure. Note: The rearcaliper is similar in design to the front caliperon 5-series models.

Overhaul4 On all calipers except the front calipers on3-Series models, remove the circlip for thedust seal (see illustration), then remove thedust boot (see illustration). Before youremove the piston, place a block of woodbetween the piston and caliper to preventdamage as it is removed.5 To remove the piston from the caliper,apply compressed air to the brake fluid hoseconnection on the caliper body (see


3.5l Hang the caliper out of the way with apiece of wire

3.5m Remove the outer brake pad - to fitthe new pads, reverse the removal

procedure

3.5k Unclip the inner brake pad from thepiston (5-Series)

3.5j Remove the caliper and inner brakepad (5-Series)

3.5i Depress the piston with a C-clamp (5-Series)

3.5h Prise off the anti-rattle spring (5-Series)

3.5g Remove the plugs for the brakecaliper mounting bolts, then remove the

bolts (5-Series)

illustration). Use only low pressure, such asthat produced by a foot pump, to ease thepiston out of its bore.

Warning: Be careful not to placeyour fingers between the pistonand the caliper, as the pistonmay come out with some force. If

you’re working on a front caliper of a 3-Series model, remove the dust boot.6 Inspect the mating surfaces of the pistonand caliper bore wall. If there is any scoring,rust, pitting or bright areas, renew thecomplete caliper unit.7 If these components are in good condition,remove the piston seal from the caliper boreusing a wooden or plastic tool (seeillustration). Metal tools may damage thecylinder bore.8 Remove the caliper guide pins or bolts andremove the rubber dust boots.9 Wash all the components using methylatedspirit or brake system cleaner.10 Using the correct overhaul kit for yourvehicle, reassemble the caliper as follows.11 Dip the new rubber seal in clean brakefluid, and refit it in the lower groove in thecaliper bore, making sure it isn’t twisted.12 On all calipers except the front calipers of3-Series models, coat the walls of the caliper

bore and the piston with clean brake fluid, andrefit the piston at this time. Do not force thepiston into the bore, but make sure that it issquarely in place, then apply firm (but notexcessive) pressure to refit it. Fit the newrubber dust boot and the retaining ring.13 On the front calipers of 3-Series models,coat the piston with clean brake fluid, andstretch the new dust boot over the bottom ofthe piston. Hold the piston over the caliperbore, and insert the rubber flange of the dustboot into the upper groove in the bore. Startwith the furthest side from you, and work yourway around towards the front until it iscompletely seated. Push the piston into thecaliper bore until it is bottomed in the bore,then seat the top of the dust boot in thegroove in the piston.14 Lubricate the sliding surfaces of the guidepins or bolts with silicone-based grease(usually supplied in the kit), and push theminto the caliper. Refit the dust boots.

Refitting15 Refit the caliper by reversing the removalprocedure (see Section 3).

Warning: Check and if necessaryrenew the mounting bolts on 3-Series models whenever they areremoved. If in doubt, use new bolts.

16 If the hose was disconnected from thecaliper, bleed the brake system (see Sec-tion 16).

5 Brake disc - inspection,removal and refitting 2

Note: This procedure applies to both the frontand rear brake discs. Brake discs shouldalways be renewed or refinished in pairs (bothfront or both rear discs) even if only one isdamaged or defective.


4.4b Remove the circlip for the dust seal

4.4a An exploded view of a typical rear caliper assembly (front calipers similar)

4.7 Remove the piston seal from thecaliper bore using a wooden or plastic tool

(metal tools may damage the cylinder bore)

1 Caliper assembly2 Bracket mounting bolt3 Bleed screw4 Dust cap5 Anti-rattle spring6 Guide bolt7 Brake pad wear warning

light wire

8 Cable clamp9 Brake disc

10 Allen bolt11 Shield12 Bolt13 Washer14 Plug

15 Plug16 Caliper bracket17 Cable clamp18 Piston seal, piston, dust

boot and circlip19 Guide bush repair kit20 Brake pads

4.5 With the caliper padded to catch thepiston, use low pressure compressed airto force the piston out of its bore - make

sure your fingers are not between thepiston and the caliper

9

Inspection1 Loosen the wheel bolts, raise the vehicleand support it securely on axle stands.Remove the wheel, and refit three bolts tohold the disc in place. If the rear brake disc isbeing worked on, release the handbrake.2 Remove the brake caliper as outlined inSection 4. It is not necessary to disconnectthe brake hose. After removing the caliper,suspend it out of the way with a piece of wire.Remove the caliper mounting bracket (seeillustration).3 Inspect the disc surface for scoring, cracksor other damage. Light scratches and shallowgrooves are normal after use, and are notusually detrimental to brake operation, butdeep scoring requires disc removal and

renewal, or (if possible) refinishing by aspecialist. If a disc is cracked it must berenewed. Be sure to check both sides of thedisc (see illustration). If severe vibration hasbeen noticed during application of the brakes,the discs may be warped (excessive run-out).If the vehicle is equipped with the Anti-lockBraking System (ABS), do not confusevibration caused by warped discs with normaloperation of the ABS. It is quite normal forsome vibration to be felt through the pedalwhen the system is working.4 To check disc run-out, place a dial indicatorat a point about 13 mm from the outer edge ofthe disc (see illustration). Set the indicator tozero, and rotate the disc. The indicatorreading should not exceed the specified

allowable run-out limit. If it does (and if therun-out is not due to wheel bearing wear), thedisc should be renewed or (if possible)refinished by a specialist. Note: It isrecommended that the discs be resurfacedregardless of the dial indicator reading, as thiswill impart a smooth finish and ensure aperfectly flat surface, eliminating any vibrationfelt through the brake pedal or otherundesirable symptoms related to questionablediscs. At the very least, if you elect not to havethe discs resurfaced, remove the glazing fromthe surface with emery cloth or sandpaper,using a swirling motion (see illustration).5 It is absolutely critical that the disc not bemachined to a thickness less than thatspecified. The minimum wear (or discard)thickness is stamped into the hub of the disc.The disc thickness can be checked with amicrometer (see illustration).

Removal6 Remove the disc retaining screw (seeillustration) and remove the disc from the hub(see illustration). If the disc is stuck to thehub, spray a generous amount of penetratingoil onto the area between the hub and the disc(see illustration) and allow a few minutes forit to loosen the rust between the twocomponents. If a rear disc still sticks, insert athin, flat-bladed screwdriver through the hubflange, rotate the starwheel on the handbrake


5.6c If the disc is stuck to the hub, spraysome penetrating oil onto the area

between the hub and the disc, and give theoil a few minutes to separate the two parts

5.6b . . . and remove the disc from the hub

5.6a Remove the disc retaining screw . . .

5.5 The disc thickness can be checkedwith a micrometer

5.4b Using a swirling motion, remove theglaze from the disc surface with

sandpaper or emery cloth

5.4a To check disc run-out, mount a dialindicator as shown, and rotate the disc

5.3 The brake pads on this vehicle wereobviously neglected, as the backing platecut deep grooves into the disc - wear thissevere means the disc must be renewed

5.2 Remove the caliper mounting bracketbolts (arrowed) and remove the bracket

adjusting screw and contract the handbrakeshoes (see illustration).

Refitting7 Ensure that the disc is completely cleanbefore refitting. If penetrating oil was used toremove the disc, make sure that no trace ofthis is present. Place the disc on the hub, andrefit the disc retaining screw. Tighten thescrew securely.8 Refit the caliper mounting bracket (ifremoved), brake pads and caliper (seeSections 3 and 4). Tighten all fasteners to thetorques listed in this Chapter’s Specifications.9 Refit the wheel, then lower the vehicle tothe ground. Depress the brake pedal a fewtimes to bring the brake pads into contactwith the disc.10 Adjust the handbrake shoes, if necessary(Section 11).11 Check the operation of the brakescarefully before returning the vehicle tonormal service.

6 Drum brake shoes - renewal 2Warning: Brake shoes must berenewed on both wheels at thesame time - never renew theshoes on only one wheel. Also,

the dust created by the brake system maycontain asbestos, which is harmful to yourhealth. Never blow it out with compressedair, and don’t inhale any of it. Always wearan approved filtering mask when servicingthe brake system. Do not, under any

circumstances, use petroleum-basedsolvents to clean brake parts. Use brakesystem cleaner only.

Caution: Whenever the brakeshoes are renewed, new returnand hold-down springs and newautomatic adjuster thermo-clips

should also be fitted. Due to thecontinuous heating/cooling cycle to whichthe springs are subjected, they may losetheir tension over a period of time,allowing the shoes to drag on the drum,and wear at a much faster rate thannormal. When fitting new brake shoes, useonly original-equipment or high-qualitybrand name parts.Note 1: All four rear brake shoes must berenewed at the same time, but to avoid mixingup parts, work on only one brake assembly ata time. Some rear brake components aredifferent for left and right-hand sides, so don’tmix them up.Note 2: If the wheel cylinder is found to beleaking or otherwise defective, renew it afterremoving the brake shoes. This is simply amatter of disconnecting the hydraulic line andunbolting the cylinder from the backplate.Attempting to overhaul a leaking cylinder isunlikely to be satisfactory, even if spare partsare available.1 Chock the front wheels, then loosen therear wheel bolts, raise the rear of the vehicleand place it securely on axle stands. Removethe rear wheels and release the handbrake.2 Remove the drum retaining screw (seeillustration) and remove the drum. If the drumis stuck to the hub, spray the area betweenthe hub and the drum with penetrating oil(see illustration). If the drum still won’t comeoff, the shoes have probably worn ridges intothe drum, and will have to be retracted. Inserta narrow flat-bladed screwdriver through oneof the holes in the hub flange (seeillustration) and back off the adjuster wheeluntil the drum can be removed.3 Inspect the drum for cracks, score marks,deep scratches and hard spots, which willappear as small discoloured areas. If the hardspots can’t be removed with emery cloth or ifany of the other conditions exist, the drum mustbe taken to a specialist to have the drumresurfaced. Note: Professionals recommend

resurfacing the drums whenever a brake job isdone. Resurfacing will eliminate the possibilityof out-of-round drums. If the drums are worn somuch that they can’t be resurfaced withoutexceeding the maximum allowable diameter(which is cast into the drum) (see illustration),then new ones will be required. At the very least,if you elect not to have the drums resurfaced,remove the glazing from the surface with emerycloth or sandpaper, using a swirling motion.


6.2b If the drum is stuck to the hub, applypenetrating oil around the hub/drum area,

and give it a few minutes to loosen up any rust

6.2a Removing the drum retaining screw5.6d If a rear disc still sticks to the hub,insert a thin, flat-bladed screwdriver

through the hub flange, rotate thestarwheel on the handbrake adjusting

screw, and contract the handbrake shoes(disc removed for clarity)

6.3 The maximum allowable insidediameter of the drum is cast into the drum

6.2c If the brake shoes have worn agroove in the drum and it won’t come off,

insert a thin flat-bladed screwdriverthrough one of the wheel bolt holes in theflange, and loosen the automatic adjuster

mechanism (for the sake of clarity, thedrum has already been removed in this

photo, and the screwdriver is beinginserted underneath the flange instead of

though a wheel bolt hole)

9

If the front disc is stuck, onsome discs it is possible tothread two or three bolts intothe holes provided and

tighten them. Alternate between thebolts, turning them a couple of turns ata time, until the disc is free.

4 Unhook and remove the lower return spring(see illustrations).5 Unhook and remove the upper return spring(see illustrations).6 Remove the front and rear brake shoe hold-down springs (see illustrations).7 Remove the front shoe (see illustration).8 Remove the adjuster assembly (seeillustration). Clean the adjuster and makesure that the adjuster wheel moves freely onthe threads. It is recommended that thethermo-clip (the spring clip next to the

adjuster wheel) be renewed whenever newshoes are fitted. Turn the adjuster wheel sothat the assembly is at its shortest positionready for refitting.9 Disconnect the handbrake cable from thehandbrake lever, and remove the rear shoe(see illustration).10 Refitting is basically the reverse ofremoval, but note the following points.11 Apply a smear of high-temperature brakegrease to the backing plate (see illustration).Be careful not to get grease onto the


6.11 Before you fit the new shoes, applysome high-temperature brake grease to

the friction surfaces where the inner edgeof the shoe slides on the brake backing

plate - when you refit the automaticadjuster mechanism, make sure each endengages properly with its respective notch

in the brake shoe

6.9 To disconnect the handbrake cablefrom the handbrake lever, pull on the plug

at the end of the cable, and detach thecable from the bracket on the upper end ofthe lever (diagonal cutting pliers are being

used here because they grip the cablewell, but care must be taken not to nick

the cable)6.8 Remove the automatic adjuster

assembly

6.7 Remove the front shoe, automaticadjuster lever and spring as an assembly,then remove the lever and spring, and set

them aside for attachment to the new shoe

6.6b . . . and the rear shoe hold-down spring

6.6a Remove the front shoe hold-down spring . . .

6.5b . . . then unhook it from the rear shoeand remove it

6.5a Unhook the upper return spring fromthe front shoe . . .

6.4b . . . then unhook it from the rear shoeand remove it

6.4a Unhook the lower return spring fromthe front shoe . . .

friction surfaces of the brake shoes or drums.12 Make sure the adjuster assembly isproperly engaged with its respective notch inthe handbrake lever.13 When refitting the automatic adjustmentmechanism, fit the lever on the shoe first (seeillustration), then hook the lower end of thespring onto the lever and the upper end intoits hole in the front shoe (see illustration).14 When you’re done, the brake assemblyshould look like this (see illustration). Nowproceed to the other brake.15 When you’re done with both brakes, refitthe brake drums. 16 If the wheel cylinder was renewed (seeNote 2), bleed the hydraulic system asdescribed in Section 16.17 Depress the brake pedal repeatedly toactuate the self-adjusting mechanism. Aclicking sound will be heard from the brakedrums as the adjusters take up the slack.18 Check the handbrake adjustment (Sec-tion 11).19 Refit the wheels and bolts. Lower thevehicle to the ground, and tighten the wheelbolts to the torque listed in the Chapter 1Specifications. Check the operation of thebrakes carefully before driving the vehicle intraffic.

7 Master cylinder - removal and refitting 3


Note: Although master cylinder parts andoverhaul kits are available for most models, werecommend fitting a new or overhauledmaster cylinder complete. It will take you moretime to overhaul the master cylinder than torenew it, and you can’t even determinewhether the master cylinder is in good enoughcondition to overhaul it until you havedismantled it. You may very well find that it

can’t be overhauled because of its internalcondition.

Removal1 The master cylinder is connected to thebrake vacuum servo, and both are attached tothe bulkhead, located on the left-hand side ofthe engine compartment (see illustration).2 Remove as much fluid as you can from thereservoir with a syringe.3 Place rags under the line fittings, andprepare caps or plastic bags to cover theends of the lines once they are disconnected.

Caution: Brake fluid will damagepaint. Cover all body parts, andbe careful not to spill fluid duringthis procedure.

4 Loosen the union nuts at the ends of thebrake lines where they enter the mastercylinder. To prevent rounding off the flats onthese nuts, a split ring (“brake”) spanner,which wraps around the nut, should be used.5 Pull the brake lines away from the mastercylinder slightly, and plug the ends to preventdirt contamination and further fluid loss.6 Disconnect any electrical connectors at themaster cylinder, then remove the nuts

attaching the master cylinder to the brakeservo. Pull the master cylinder off the studs,and lift it out of the engine compartment.Again, be careful not to spill fluid as this isdone. Discard the old O-ring (see illustration)between the master cylinder and the servounit.

Warning: The O-ring shouldalways be renewed. A faulty O-ring can cause a vacuum leak,

which can reduce braking performanceand cause an erratic idle.

Bleeding procedure7 Before fitting a new or overhauled mastercylinder, it should be bled on the bench.Because it will be necessary to apply pressureto the master cylinder piston and, at the sametime, control flow from the brake line outlets, itis recommended that the master cylinder bemounted in a vice. Use a vice with protectedjaws, and don’t clamp the vice too tightly, orthe master cylinder body might crack.8 Insert threaded plugs into the brake lineoutlet holes. Tighten them down so that therewill be no air leakage past them, but not sotight that they cannot be easily loosened.9 Fill the reservoir with brake fluid of therecommended type (see “Lubricants, fluidsand capacities” in Chapter 1).10 Remove one plug, and push the pistonassembly into the master cylinder bore to


6.14 When you get everything backtogether, this is how it

should look!

6.13b . . . then hook the lower end of thespring onto the lever as shown; stretch the

spring, and hook the upper end into itshole in the handbrake shoe

6.13a Refit the automatic adjuster leverfirst - make sure it’s properly engaged with

the notch in the front end of the adjuster mechanism . . .

7.6 Always renew the O-ring (1) - groovearrowed - between the master cylinder and

the brake servo

7.1 To remove the master cylinder, unplugthe electrical connector (top arrow),

disconnect the brake fluid hydraulic linefittings (lower right arrow, other fitting notvisible in this photo) and remove the twomaster cylinder mounting nuts (lower leftarrow, other nut not visible in this photo) -5-Series master cylinder shown, 3-Series

similar

9

expel the air from the master cylinder. A largePhillips screwdriver can be used to push onthe piston assembly.11 To prevent air from being drawn back intothe master cylinder, the plug must be refittedand tightened down before releasing thepressure on the piston assembly.12 Repeat the procedure until brake fluid freeof air bubbles is expelled from the brake lineoutlet hole. Repeat the procedure with theother outlet hole and plug. Be sure to keep themaster cylinder reservoir filled with brakefluid, to prevent the introduction of air into thesystem.13 High pressure is not involved in the benchbleeding procedure, so the plugs describedabove need not be refitted each time thepiston is released, if wished. Instead, beforereleasing the piston, simply put your fingertightly over the hole to keep air from beingdrawn back into the master cylinder. Waitseveral seconds for brake fluid to be drawnfrom the reservoir into the piston bore, thendepress the piston again, removing yourfinger as brake fluid is expelled. Be sure to putyour finger back over the hole each timebefore releasing the piston, and when thebleeding procedure is complete for that outlet,refit the plug and tighten it up before going onto the other port.

Refitting14 Refit the master cylinder (together with anew O-ring) over the studs on the brake servo,and tighten the mounting nuts only finger-tightat this time.15 Thread the brake line fittings into themaster cylinder. Since the master cylinder isstill a bit loose, it can be moved slightly inorder for the fittings to thread in easily. Do notstrip the threads as the fittings are tightened.16 Tighten the brake fittings securely, andthe mounting nuts to the torque listed in thisChapter’s Specifications.17 Fill the master cylinder reservoir with fluid,then bleed the master cylinder (only if thecylinder has not already been bled) and thebrake system as described in Section 16.18 To bleed the cylinder on the vehicle, havean assistant pump the brake pedal several

times and then hold the pedal to the floor.Loosen the fitting nut to allow air and fluid toescape, then tighten the nut. Repeat thisprocedure on both fittings until the fluid isclear of air bubbles. Test the operation of thebrake system carefully before returning thevehicle to normal service.

8 Brake vacuum servo - check, removal and refitting 3

Operating check1 Depress the brake pedal several times withthe engine off, until there is no change in thepedal travel.2 Depress and hold the pedal, then start theengine. If the pedal goes down slightly,operation is normal.

Airtightness check3 Start the engine, and turn it off after one ortwo minutes. Depress the brake pedal severaltimes slowly. If the pedal goes down furtherthe first time but gradually rises after thesecond or third depression, the servo isairtight.4 Depress the brake pedal while the engine isrunning, then stop the engine with the pedaldepressed. If there is no change in the pedaltravel after holding the pedal for 30 seconds,the servo is airtight.

Removal and refitting5 Dismantling the vacuum servo requiresspecial tools, and cannot be performed by thehome mechanic. If a problem develops, it isrecommended that a new unit be fitted.6 Remove the master cylinder as described inSection 7.7 Disconnect the vacuum hose from thebrake servo.8 Working in the passenger compartment,remove the glovebox and lower left-hand trimpanels.9 Remove the clip and clevis pin todisconnect the pushrod from the cross-shaftlever (right-hand-drive models) or brake pedal

(left-hand-drive models) (see illustration). Onleft-hand-drive models, also disconnect thebrake pedal return spring.10 Remove the four mounting nuts (seeillustration) and withdraw the servo unit fromthe engine compartment.11 Inspect the small foam filter (seeillustration) inside the rubber boot on thepushrod. If the filter is clogged, it may affectthe servo’s performance. To clean the filter,wash it in a mild soapy solution. If it’s stilldirty, renew it.12 Refitting is the reverse of the removalprocedure. Tighten the brake servo mountingnuts to the torque listed in this Chapter’sSpecifications. Before you slide the boot intoplace over the servo pushrod air filter, makesure the notches in the filter offset the notchesin the damper by 180 degrees.13 On 3-Series models, adjust the basicsetting of the pushrod’s threaded clevis untilthe dimension is correct (see illustration).When the basic setting is correct, tighten thelocknut, then adjust the brake pedal travel and


8.13 On 3-Series models, adjust dimension A (the distance between the

middle of the brake lever and thebulkhead/”firewall”) by loosening the

locknut (1) at the pushrod clevis (2) andturning the threaded part of the pushroduntil dimension A matches the dimension

listed in this Chapter’s Specifications.When the basic setting is correct, tightenthe locknut, then adjust the brake pedal

height and the stop-light switch

8.11 An exploded view of a typical servopushrod assembly

1 Boot 2 Holder 3 Damper 4 Air filter

8.10 Remove the four mounting nuts(arrows) and withdraw the servo unit from

the engine compartment (left-hand-drive model shown)

8.9 Disconnect the brake pedal returnspring, then remove the clip and clevis pin(arrows) to disconnect the pushrod fromthe brake pedal (left-hand-drive models)

the stop-light switch (see Section 13). Note:On right-hand-drive models, the brake pedalin on the right-hand side of the vehicle, and isconnected to the left-hand side by a cross-shaft. The adjustment is carried out on thepushrod at the left-hand side, but thedimension is measured at the pedal on theright-hand side.14 On 5-Series models, adjust the brakepedal height and the stop-light switch (seeSection 13).15 Refit the master cylinder (see Section 7)and attach the vacuum hose.16 Carefully test the operation of the brakesbefore returning the vehicle to normal use

9 Hydraulic brake servo -description, removal andrefitting

3Warning: Brake fluid ispoisonous. It is also an effectivepaint stripper. Refer to thewarning at the start of Section 16.

Description1 On 5-Series E28 (“old-shape”) models, ahydraulic brake servo system is fitted. Theservo unit, located between the brake pedal(left-hand-drive) or cross-shaft lever (right-hand-drive) and the master cylinder, isoperated by hydraulic pressure generated bythe power steering pump. When the engine isrunning, the power steering pump supplieshydraulic pressure to a power flow regulator/accumulator. The regulator/accumulatorstores and regulates the pressure to thehydraulic brake servo. When you press thebrake pedal, the pressure in the servo helpsactuate the master cylinder, reducing pedaleffort.2 The hydraulic brake servo cannot beoverhauled; if it fails, a new one must be fitted.Testing the system requires special tools, soeven fault diagnosis is beyond the scope ofthe home mechanic. If the system fails, take itto a dealer service department or otherqualified garage for repairs.

Removal and refitting3 With the engine off, discharge the hydraulicaccumulator by depressing the brake pedal20 times or more.4 Remove the master cylinder (see Section 7).5 Clean the area around the return andsupply line fittings, then disconnect them.Plug the lines, to prevent dirt from entering thesystem, and to prevent further fluid loss.

Caution: Even a particle of dirtcan damage the servo, so beextremely careful to prevent dirtfrom entering the system whilethe lines are disconnected.

6 Working from inside the passengercompartment, remove the lower left trimpanels above the brake pedal (left-hand-drivemodels) or glovebox and trim (right-hand-

drive models). On left-hand-drive models, alsodisconnect the pedal return spring.7 Prise off the retaining clip, and disconnectthe pushrod from the brake pedal (seeillustration 8.9) or cross-shaft lever.8 Remove the four mounting nuts andremove the brake servo (see illus-tration 8.10).9 Refitting is the reverse of removal. Tightenthe hydraulic lines to the torque listed in thisChapter’s Specifications. Note: Don’t try totighten these fittings without a torque wrench.If they’re loose, they can leak, which can affectsystem operation; if they’re tight, they can bedamaged, and they’ll also leak. You’ll need acrowfoot-type split ring (“brake”) attachmentfor your torque wrench to tighten the fittingsproperly. 10 When you’re done, bleed the brakehydraulic system (Section 16) and adjust thebrake pedal travel and the stop-light switch(see Section 13).

10 Handbrake cable(s) - renewal 21 Peel back the boot at the base of thehandbrake lever, and remove the handbrakecable adjusting nut (see illustration) whichalso secures the cable to the handbrake lever.

There are two cables - one for each rear wheel- and a nut for each cable. On some models, itmay be necessary to remove the centreconsole completely for access.2 Raise the vehicle and support it securely onaxle stands.3 Remove the rear brake drum (see Section 6)or rear brake disc (see Section 5).4 On rear drum models, unhook thehandbrake cable from the lever on the rearbrake shoe (see Section 6). On rear discmodels, remove the handbrake shoes and theactuator (see Section 12) and unhook thehandbrake cable from the actuator (seeillustrations). 5 On rear drum models, pull the cable andcable conduit (tube) out of the back of thebrake backplate, then detach the cableconduit from the cable clips on the back ofthe trailing arm (it’s easier to pull out the oldcable, and fit the new cable, with the conduitstraight instead of curved). On rear discmodels, it’s unnecessary to detach the cableconduit from the brake backplate, but it’s agood idea to detach the conduit from the clipsand guides securing it to the trailing arm, totake some of the bend out of the conduit.6 Working from the wheel end of the cableconduit, pull the cable out of the conduit (seeillustration).7 Lubricate the new cable with multi-purposegrease, then insert it into the cable conduit


10.1 Peel back the handbrake lever bootand remove the relevant handbrake cable

adjusting nut (both arrowed)

10.6 Pull the cable out of its conduit;before you refit the new cable, be sure to

lubricate it with multi-purpose grease

10.4b . . . then remove the pin securing thecable to the inner cam, and remove the

inner cam

10.4a To detach the handbrake cable fromthe handbrake actuator on models with rear

disc brakes, pull on the outer cam anddisconnect it from the inner cam . . .

9

and push it through until the forward endcomes out at the handbrake lever.8 Insert the cable conduit through thebackplate, and attach the rear end of thecable to the handbrake lever (rear drummodels) or the actuator (rear disc models).Make sure you don’t kink the cable whileconnecting it. 9 Refit the cable conduit to the clips on theback of the trailing arm.10 On rear drum models, refit the brakeshoes and drum (see Section 6). On rear discmodels, refit the handbrake shoes andactuator (see Section 12) and the rear brakedisc (see Section 5).11 Lower the vehicle, and refit the adjustingnut at the handbrake lever. Adjust thehandbrake cable (see Section 11) and refit thehandbrake lever boot.

11 Handbrake - adjustment 2Rear drum brake modelsNote: Adjustment of the handbrake cable(s)on models with rear drum brakes should onlybe necessary when you renew a cable ordetach if from the rear brake assembly forsome reason. Failure of the handbrake systemto hold the vehicle usually indicates wornbrake shoes or a faulty self-adjustingmechanism.1 Raise the rear of the vehicle, and place itsecurely on axle stands.2 Fully release the handbrake lever, thenapply the brakes firmly several times with thefootbrake pedal.3 Pull the handbrake lever up five clicks.4 Tighten or loosen the adjusting nuts byequal amounts until the rear brake shoes justbegin to drag on the brake drum. You shouldfeel the same amount of resistance at bothwheels when you rotate them.5 Release the handbrake lever, and verify thatthe wheels rotate freely. If they don’t, re-adjust them.

Rear disc brake modelsNote: The handbrake system is not self-adjusting on models with rear disc brakes. Thehandbrake therefore requires periodicadjustment to compensate for wear. It shouldalso be adjusted anytime either cable, brakedisc or handbrake assembly is renewed orremoved for some reason.6 Slowly apply the handbrake, and count thenumber of clicks at the lever. If the lever canbe pulled up further than the eighth click,adjust the handbrake cable as follows.7 Peel back the handbrake lever boot, andloosen the cable adjusting nut (seeillustration 10.1). On some models, it may benecessary to remove the centre consolecompletely for access.8 Loosen a single bolt in each rear wheel.

Raise the vehicle and place it securely on axlestands.9 Remove the bolt you loosened in each rearwheel. Turn the wheel until, using a torch, youcan see the adjuster starwheel through thebolt hole.10 Turn the adjuster - clockwise to expandthe shoes, anti-clockwise to retract them -until the brake shoes just contact the brakedrum (see illustration 5.6d). Back off thebrake shoes so the wheel spins freely (three tofour teeth on the adjuster). Note: If theadjuster starwheel is hard to turn, remove thewheel and brake disc, lubricate the adjusterwheel, and try again.11 With the disc fitted, apply the handbrakethree times to stretch and seat the cables,then slowly pull up on the handbrake lever tothe fifth click. Tighten the cable adjusting nutsby equal amounts until the rear brake shoesjust touch the brake drum. Verify that bothwheels have the same amount of resistance.12 Release the handbrake, and verify thatboth rear wheels rotate freely.13 Tighten the wheel bolts to the torquelisted in Chapter 1 Specifications.

12 Handbrake assembly -check, removal and refitting 2

Warning: The handbrake liningson rear disc brake models maybe manufactured of asbestos-based material. Refer to the

warning at the start of Section 6. Whenservicing these components, do not createdust by grinding or sanding the linings.1 The handbrake system should be checkedregularly. With the vehicle parked on a hill,apply the handbrake, select neutral, andcheck that the handbrake alone will hold thevehicle when the footbrake is released (besure to stay in the vehicle during this check).However, every 2 years (or whenever a fault issuspected), the assembly itself should beinspected.2 With the vehicle raised and supported on

axle stands, remove the rear wheels.3 On rear brake drum models, refer toChapter 1; checking the thickness of thebrake shoes is a routine maintenanceprocedure.4 On rear disc brake models, remove the reardiscs as outlined in Section 5. Support thecaliper assemblies with a coat hanger orheavy wire; do not disconnect the brake linefrom the caliper.5 With the disc removed, the handbrakecomponents are visible, and can be inspectedfor wear and damage. The linings should lastthe life of the vehicle. However, they can weardown if the handbrake system has beenimproperly adjusted, or if the handbrake isregularly used to stop the vehicle. There is nominimum thickness specification for thehandbrake shoes, but as a rule of thumb, ifthe shoe material is less than 1.5 mm thick,you should renew them. Also check thesprings and adjuster mechanism and inspectthe drum for deep scratches and otherdamage.

Removal and refittingNote: The following procedure applies only tomodels with rear disc brakes. The handbrakesystem on models with rear drum brakes is anintegral part of the rear brake assembly (seeSection 6).6 Loosen the rear wheel bolts, raise the rearof the vehicle and place it securely on axlestands. Remove the rear wheels. Remove thebrake discs (see Section 5). Work on only oneside at a time, so you can use the other sideas a reference during reassembly, and toavoid mixing up parts.7 Remove the shoe return and hold-downsprings (see illustrations).8 Remove the shoes (see illustration).9 Refitting is the reverse of removal. Whenyou’re done, the actuator should be properlyseated between the two shoes as shown (seeillustration).10 After refitting the brake disc, adjust thehandbrake shoes. Temporarily refit two wheelbolts, turn the adjuster (see illustration 5.6d)and expand the shoes until the disc locks,


12.7b Remove the upper shoe return spring

12.7a Remove the lower shoe returnspring (diagonal cutting pliers are beingused here because they grip the spring

well, but care must be taken not to cut ornick the spring)

then back off the adjuster until the shoesdon’t drag (see Section 11). Refit the wheelbolts, and tighten them to the torque given inChapter 1 Specifications.

13 Brake pedal - adjustment 1Note: You should always adjust brake pedalheight after the master cylinder or brake servohas been removed or renewed. You shouldalso adjust the stop-light switch (see Sec-tion 14).1 Measure the distance between the loweredge of the brake pedal footpad (ie the edgefurthest from the bulkhead) and the bulkhead(see illustration), and compare yourmeasurement with the dimension listed in thisChapter’s Specifications. If it’s not as listed,loosen the locknut on the pushrod, and rotate

the pushrod while holding the clevis stationaryuntil the distance is correct. Note: On right-hand-drive models, the adjustment is carriedout at the left-hand side of the cross-shaft,after removing the glovebox, but thedimension is still measured at the pedal.

14 Stop-light switch - check and adjustment 1

Note: The stop-light switch should bechecked and, if necessary, adjusted after themaster cylinder or brake servo has beenremoved or renewed.1 The stop-light switch is located on abracket at the top of the brake pedal. Theswitch activates the brake lights whenever thepedal is depressed.2 With the brake pedal in the rest position,measure the distance between the switchcontact point on the brake pedal and theswitch housing (see illustration) andcompare your measurement with dimension Alisted in this Chapter’s Specifications.3 If your measurement is outside the

indicated dimension, disconnect the wiresfrom the switch. Loosen the locknuts, screwthe switch in or out until the plungerdimension is correct, and retighten thelocknuts. Reconnect the wires and check forcorrect operation.

15 Brake hoses and lines -inspection and renewal 4


Inspection1 At the intervals specified in Chapter 1, thebrake hoses and lines should be inspected.With the vehicle raised and placed securelyon axle stands, the flexible hoses should bechecked for cracks, chafing of the outercover, leaks, blisters and other damage.These are important and vulnerable parts ofthe brake system, and inspection should bethorough. The metal pipes should be checkedfor excessive pitting and corrosion. If a hoseor pipe exhibits any of the conditionsdescribed, renew it.

Flexible hose renewal2 Clean all dirt away from the ends of thehose. Have ready a suitable container to catchspilled brake fluid when the hose isdisconnected.3 To disconnect the hose at the chassis end,use a spanner to hold the hex-shaped fittingon the end of the flexible hose, and loosen thenut on the metal brake line (see illustration).If the nut is stuck, soak it with penetrating oil.After the hose is disconnected from the metalline, remove the spring clip from the bracketand detach the hose from the bracket.4 To detach the flexible hose from the caliper,


12.9 When you’re done, the actuatorshould be properly seated between thetwo shoes as shown (hub removed for

clarity)

12.8 Remove the shoes12.7c Remove the shoe hold-down springs

14.2 To adjust the stop-light switch,loosen the locknuts (1) and screw the

switch (2) in or out until dimension A iscorrect

13.1 To adjust the brake pedal height,loosen the locknut (1) and turn the

pushrod (2) while holding the clevis (3) untildimension A (the distance between thelower edge of the brake pedal and thebulkhead/”firewall”) is within the range

listed in this Chapter’s Specifications (left-hand-drive shown, right-hand-drive similar)

9

A torch and mirror will provehelpful for a complete hoseand line check.

simply unscrew it. Plug the open fitting in thecaliper if the hose is removed for any length oftime, to prevent dirt ingress.5 Refitting is the reverse of the removalprocedure. Make sure the brackets are ingood condition and the locknuts are securelytightened. Renew the spring clips if they don’tfit tightly.6 Carefully check to make sure thesuspension and steering components do notmake contact with the hoses. Have anassistant turn the steering wheel from lock-to-lock during inspection.7 Bleed the brake system as described inSection 16.

Metal brake line renewal8 When renewing brake lines, use genuineparts only - preferably from a BMW dealer.9 Genuine BMW brake lines are suppliedstraight. You’ll need a pipe-bending tool tobend them to the proper shape.10 First, remove the line you intend to renew,lay it on a clean workbench and measure itcarefully. Obtain a new line of the samelength, and bend it to match the pattern of theold line.

Warning: Do not crimp ordamage the line. No bend shouldhave a smaller radius than 14 mm. Make sure the protective

coating on the new line is undamaged atthe bends.

11 When fitting the new line, make sure it’swell supported by the brackets, that therouting matches the original, and that there’splenty of clearance between movablecomponents or those components which willbecome hot.12 After refitting, check the master cylinderfluid level, and add fluid as necessary. Bleedthe brake system as outlined in Section 16,and test the brakes carefully before driving thevehicle. Be sure there are no leaks.

16 Brake hydraulic system -bleeding 3

Warning: Wear eye protectionwhen bleeding the brake system.If the fluid comes in contact withyour eyes, immediately rinse

them with water, and seek medicalattention. Most types of brake fluid arehighly flammable, and may ignite if spilledonto hot engine components, for example.In this respect, brake fluid should betreated with as much care as if it werepetrol. When topping-up or renewing thefluid, always use the recommended type,and ensure that it comes from a freshly-opened sealed container. Never re-use oldbrake fluid bled from the system, and don’ttop-up with fluid which has been standingopen for a long time, as it is potentiallydangerous to do so.

Note: Bleeding the hydraulic system isnecessary to remove any air which hasentered the system during removal andrefitting of a hose, line, caliper or mastercylinder.1 It will probably be necessary to bleed thesystem at all four brakes if air has entered thesystem due to low fluid level, or if the brakelines have been disconnected at the mastercylinder.2 If a brake line was disconnected at only onewheel, then only that caliper or wheel cylinderneed be bled.3 If a brake line is disconnected at a fittinglocated between the master cylinder and anyof the brakes, that part of the system servedby the disconnected line must be bled.4 Bleed the right rear, the left rear, the rightfront and the left front brake, in that order,when the entire system is involved.5 Remove any residual vacuum from thebrake servo by applying the brakes about 30times with the engine off. This will also relieveany pressure in the anti-lock brake system(where applicable).6 Remove the master cylinder reservoircover, and fill the reservoir with brake fluid.Refit the cover. Note: Check the fluid leveloften during the bleeding operation, and addfluid as necessary to prevent the fluid levelfrom falling low enough to allow air into themaster cylinder.7 Have an assistant on hand, an empty clearplastic container, and a length of clear plasticor vinyl tubing to fit over the bleed screws.Alternatively, a “one-man” bleeding kit can beused. A “one-man” kit usually contains a tube

or bottle with a one-way valve incorporated -in this way, the pedal can be pumped asnormal, but air is not drawn back into thesystem when the pedal is released. If a one-man kit is used, follow the instructionsprovided with it; similarly with pressurebleeding kits. In any case, you will also need asupply of new brake fluid of therecommended type, and a spanner for thebleed screw.8 Beginning at the right rear wheel, loosen thebleed screw slightly, then tighten it to a pointwhere it is tight but can still be loosenedquickly and easily.9 Place one end of the tubing over the bleednipple, and submerge the other end in brakefluid in the container (see illustration).10 Have the assistant pump the brakes a fewtimes, then hold the pedal firmly depressed.Note: If the vehicle is equipped with ABS,have the assistant pump the pedal at least 12times.11 While the pedal is held depressed, openthe bleed screw just enough to allow a flow offluid to leave the caliper or wheel cylinder.Your assistant should press the brake pedalsmoothly to the floor, and hold it there. Watchfor air bubbles coming out of the submergedend of the tube. When the fluid flow slowsafter a couple of seconds, close the screwand have your assistant release the pedal.12 Repeat paragraphs 10 and 11 until nomore air is seen leaving the tube, then tightenthe bleed screw and proceed to the left rearwheel, the right front wheel and the left frontwheel, in that order, and perform the sameprocedure. Be sure to check the fluid in themaster cylinder reservoir frequently.

Warning: Never re-use old brakefluid. It absorbs moisture fromthe atmosphere, which can allowthe fluid to boil and render thebrakes inoperative.

13 Refill the master cylinder with fluid at theend of the operation.14 Check the operation of the brakes. Thepedal should feel solid when depressed, withno sponginess. If necessary, repeat the entireprocess. Do not operate the vehicle if you arein doubt about the effectiveness of the brakesystem.


16.9 Place one end of the tubing over thebleed screw, and submerge the other end

in brake fluid in the container

15.3 A typical brake line-to-brake hoseconnection: To disconnect it, use one

spanner to hold the hex-shaped fitting onthe end of the flexible hose (lower right

arrow) and loosen the threaded fitting onthe metal line with a split ring (“brake”)

spanner (upper right arrow), then removethe spring clip (left arrow)

Brake fluid is an effectivepaint stripper, and will attackplastics; if any is spilt, wash itoff immediately with copiousamounts of water.

10

GeneralPower steering fluid type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1

TyresTyre sizes

3-Series, E30316 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175/70x14316i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175/70x14, 195/65x14318i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175/70x14320i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/65x14325i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/65x14, 200/60x356, 205/55x15

5-Series, E28 (“old-shape”)518 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175x14518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175x14525i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175x14, 195/70x14528i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/70x14535i and M535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220/55x390

5-Series, E34 (“new-shape”)518i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/65x15520i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/65x15, 225/60x15525i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195/65x15, 205/65x15, 225/65x15530i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205/65x15, 225/60x15535i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225/60x15, 240/45x415

Tyre pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1 Specifications

Chapter 10 Suspension and steering systems

Balljoints - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Control arm (3-Series) - inspection, removal and refitting,

and bush renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Control and thrust arms (5-Series) - inspection, removal and

refitting, and bush renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Front anti-roll bar - removal and refitting . . . . . . . . . . . . . . . . . . . . . 2Front hub and wheel bearing assembly - removal and refitting . . . . 8Front strut assembly - removal and refitting . . . . . . . . . . . . . . . . . . . 5General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Power steering fluid level check . . . . . . . . . . . . . . . . See Chapter 1Power steering pump - removal and refitting . . . . . . . . . . . . . . . . . . 22Power steering system - bleeding . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Rack-and-pinion steering gear (3-Series) - removal and refitting . . . 19Rear anti-roll bar - removal and refitting . . . . . . . . . . . . . . . . . . . . . . 12Rear coil springs (3-Series) - removal and refitting . . . . . . . . . . . . . . 10Rear shock absorbers (3-Series) - removal and refitting . . . . . . . . . 9Rear shock absorber/coil spring assembly (5-Series) - removal

and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Rear trailing arms (3-Series) - removal and refitting . . . . . . . . . . . . . 13Rear trailing arms (5-Series) - removal and refitting . . . . . . . . . . . . . 14Rear wheel bearings - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Steering and suspension check . . . . . . . . . . . . . . . . . See Chapter 1Steering box (5-Series) - removal and refitting . . . . . . . . . . . . . . . . . 21Steering gear boots (3-Series) - renewal . . . . . . . . . . . . . . . . . . . . . . 18Steering linkage (5-Series) - inspection, removal and

refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Steering system - general information . . . . . . . . . . . . . . . . . . . . . . . 16Steering wheel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 24Strut or shock absorber/coil spring - renewal . . . . . . . . . . . . . . . . . . 6Suspension and steering checks . . . . . . . . . . . . . . . . See Chapter 1Track rod ends - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 17Tyre and tyre pressure checks . . . . . . . . . . . . . . . . . See Chapter 1Tyre rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1Wheel alignment - general information . . . . . . . . . . . . . . . . . . . . . . . 26Wheels and tyres - general information . . . . . . . . . . . . . . . . . . . . . . 25

10•1







Specifications

Contents

Torque wrench settings Nm

Front suspensionStrut damper rod nut

Rod with external hexagon . . . . . . . . . . . . . . . . . . . . . . 65Rod with internal hexagon . . . . . . . . . . . . . . . . . . . . . . 44

Strut cartridge threaded collar . . . . . . . . . . . . . . . . . . . . . . . 130Strut upper mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . 22Front control arm (3-Series)

Control arm-to-steering knuckle balljoint nut . . . . . . . . . . 64Control arm-to-subframe balljoint nut . . . . . . . . . . . . . . . 83Control arm bush bracket bolts . . . . . . . . . . . . . . . . . . . . 41

Lower control arm (5-Series)Control arm-to-steering arm balljoint stud nut . . . . . . . . . 85Control arm pivot bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Thrust arm (5-Series)Thrust arm-to-steering arm balljoint stud nut . . . . . . . . . . 85Thrust arm through-bolt . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Front hub (wheel bearing) nut . . . . . . . . . . . . . . . . . . . . . . . . 290Steering arm-to-strut bolts (5-Series) . . . . . . . . . . . . . . . . . . 65Anti-roll bar (3-Series)

Anti-roll bar-to-connecting link bolt . . . . . . . . . . . . . . . . . 41Anti-roll bar mounting brackets-to-subframe . . . . . . . . . . 22Connecting link-to-bracket . . . . . . . . . . . . . . . . . . . . . . . . 22Connecting link bracket-to-control arm . . . . . . . . . . . . . . 41

Anti-roll bar (5-Series)Anti-roll bar mounting brackets . . . . . . . . . . . . . . . . . . . . 22Anti-roll bar link-to-strut housing locknut

Yellow chrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20White chrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Yellow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

10•2 Suspension and steering systems

Torque wrench settings Nm

Rear suspensionRear shock absorber (3-Series)

Shock absorber-to-upper mounting bracket . . . . . . . . . . 12 to 15Shock absorber-to-trailing arm . . . . . . . . . . . . . . . . . . . . 71 to 85

Rear shock absorber (5-Series)Lower mounting bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 to 142Upper mounting nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 24Upper spring mounting-to-shock absorber locknut . . . . . 22 to 24

Trailing arms (3-Series)Trailing arm-to-lower mounting . . . . . . . . . . . . . . . . . . . . 71 to 85Trailing arm-to-anti-roll bar . . . . . . . . . . . . . . . . . . . . . . . . 22 to 23

Trailing arms (5-Series)Trailing arm-to-rear axle carrier (rubber bush

through-bolt and nut) . . . . . . . . . . . . . . . . . . . . . . . . . . 66Trailing arm-to-axle carrier connecting link (1983-on) . . . 126

Rear wheel bearing drive flange axle nut (5-Series)M22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 to 210M27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 to 260

Steering systemSteering wheel retaining nut . . . . . . . . . . . . . . . . . . . . . . . . . 79Steering column universal joint pinch-bolt . . . . . . . . . . . . . . 22Steering gear-to-subframe mounting bolts (3-Series) . . . . . 41Steering box-to-front suspension subframe bolts (5-Series) 42Track rod end-to-steering arm nut . . . . . . . . . . . . . . . . . . . . 37Track rod end clamping bolt . . . . . . . . . . . . . . . . . . . . . . . . . 14Pitman arm-to-steering box (5-Series) . . . . . . . . . . . . . . . . . 140Steering linkage balljoints (all) . . . . . . . . . . . . . . . . . . . . . . . 37


Warning: Whenever any of thesuspension or steering fastenersare loosened or removed, theymust be inspected and if

necessary, new ones fitted, of the samepart number or of original-equipmentquality and design. Torque specificationsmust be followed for proper reassemblyand component retention. Never attemptto heat, straighten or weld any suspensionor steering component. Any bent ordamaged parts must be renewed.

The front suspension (see illustrations) is aMacPherson strut design. The struts aresecured at the upper ends to reinforced areasat the top of the wheel arches, and at thelower ends to the steering arms/control arms.An anti-roll bar is attached to the control armsvia connecting links, and to the suspensionsubframe (3-Series models) or the underbody(5-Series models).

The independent rear suspension systemon 3-Series models (see illustration) featurescoil springs and telescopic shock absorbers.The upper ends of the shock absorbers areattached to the body; the lower ends areconnected to trailing arms. An anti-roll bar isattached to the trailing arms via links, and tothe body with clamps.

The independent rear suspension system on5-Series models (see illustration) uses coil-

over shock absorber units instead of separateshock absorbers and coil springs. The upperends are attached to the body; the lower endsare connected to the trailing arms. The rearsuspension of 5-Series models is otherwisesimilar to that of 3-Series models: two trailingarms connected by an anti-roll bar.

The steering system consists of thesteering wheel, a steering column, a universaljoint shaft, the steering gear, the power

steering pump (where fitted) and the steeringlinkage, which connects the steering gear tothe steering arms. On 3-Series models, arack-and-pinion steering gear is attacheddirectly to the steering arms via the track rodsand track rod ends. On 5-Series models, arecirculating-ball steering box is connected tothe steering arms via a Pitman arm, a centretrack rod, the outer track rods and the trackrod ends.

1.1a Front suspension and steering components (3-Series models)

1 Subframe 3 Anti-roll bar link 5 Strut 7 Steering gear2 Anti-roll bar 4 Control arm 6 Track rod end

Suspension and steering systems 10•3

1.1b Front suspension and steeringcomponents (5-Series models -

left-hand-drive shown)

1 Subframe2 Anti-roll bar3 Anti-roll bar link4 Centre track rod5 Outer track rod6 Track rod end7 Steering arm8 Control arm9 Thrust arm

10 Strut

1.2 Rear suspension components (3-Series models)

1 Shock absorber2 Coil spring3 Driveshaft4 Trailing arm5 Rear axle carrier6 Anti-roll bar link

1.3 Rear suspension components (5-Series models - left-hand-drive shown)

1 Shock absorber/coil spring assembly2 Driveshaft3 Anti-roll bar link4 Anti-roll bar5 Trailing arm6 Rear axle carrier

10

2 Front anti-roll bar - removal and refitting 2

Removal1 Raise the front of the vehicle, and support itsecurely on axle stands.2 If you’re removing or renewing the anti-rollbar itself, or disconnecting the bar to renewthe strut assembly on a 3-Series model,disconnect it from the anti-roll bar links (seeillustrations). If you’re renewing the strutassembly on a 5-Series model, disconnect theanti-roll bar link from the strut housing.3 On 3-Series models, disconnect the leftcontrol arm rubber bush from the underbody(see Section 3).4 Remove the bolts from the anti-roll barbrackets which attach the anti-roll bar to thesubframe (see illustration).5 Remove the anti-roll bar from the vehicle.Where necessary, separate the anti-roll barfrom the strut bar bracket.

Refitting6 Refitting is the reverse of the removalprocedure. Be sure to tighten all nuts andbolts to the torques listed in this Chapter’sSpecifications.

3 Control arm (3-Series) -inspection, removal andrefitting, and bush renewal

3Inspection1 Raise the front end of the vehicle, andsupport it securely on axle stands.2 Grip the top and bottom of each balljointwith a large pair of water pump (“parrot jaw”)pliers, and squeeze to check for free play.Alternatively, insert a lever or largescrewdriver between the control arm and thesubframe or strut housing. If there’s any freeplay, renew the control arm (the balljointscan’t be renewed separately).3 Inspect the rubber bush. If it’s cracked, dry,torn or otherwise deteriorated, renew it (seebelow).

Bush renewalNote: Rubber bushes should always berenewed in pairs. Make sure both new busheshave the same markings (indicating they’remanufactured by the same firm).4 Remove the two bolts (see illustration) whichattach the bush bracket to the underbody.5 Using a puller, remove the bracket and

bush from the end of the control arm. If thepuller slips on the end of the control arm,centre-punch the control arm to give thepuller bolt a place to seat.6 Note the orientation of the old bush. This isexactly how the new bush should beorientated when it’s fitted. Press the oldrubber bush out of the bracket, or have itpressed out by an engineering works.7 Coat the end of the control arm with BMW’sspecial lubricant (Part No. 81 22 9 407 284),and press the new bush and bracket onto thearm - or have it pressed on at an engineeringworks - all the way to the stop.

Caution: Don’t try to use anyother type of lubricant; 30 minutes after it’s applied, thislubricant loses its properties and

the bush is permanently located in itsproper position. Make sure the new bushis pressed on so it’s orientated exactly thesame way as the old bush.8 Refit the bracket bolts and tighten them tothe torque listed in this Chapter’s Specifi-cations.9 Lower the vehicle, and leave it at rest for atleast 30 minutes (this will give the speciallubricant time to dry).

Control arm removal andrefittingNote: If either balljoint is worn or damaged,the only way to renew it is to renew the controlarm. If you’re fitting a new control arm, a newbush must also be fitted. The old bush can’tbe removed from the old control arm and re-used in the new control arm.10 Loosen but do not remove the wheelbolts, raise the front of the vehicle andsupport it on axle stands. Remove the wheelbolts and the front wheel.11 Remove the two bolts which attach therubber bush bracket to the underbody (seeillustration 3.4).12 Remove the nut which secures the controlarm balljoint to the subframe, and remove theballjoint stud from the subframe. Note: It maybe necessary to use a balljoint separator toseparate the balljoint from the subframe (seeillustration), but take care not to damage the


3.12 Remove the self-locking nut from theballjoint stud protruding through the top ofthe subframe (not shown in this photo, but

it’s directly above the balljoint) andseparate the balljoint from the subframe.

Try not to damage the dust boot

3.4 Remove the two bolts (arrowed)securing the bush bracket to the

underbody

2.4 Remove the bolts (arrowed) from theanti-roll bar brackets to detach the anti-

roll bar from the subframe (3-Series modelshown, 5-series similar)

2.2b On 5-Series models, remove the nut(arrowed) securing the anti-roll bar to theconnecting link (left side shown, right side

similar)

2.2a On 3-Series models, remove the nut(upper arrow) securing the anti-roll bar tothe upper end of the connecting link (leftside shown, right side similar). If a newcontrol arm is being fitted, remove the

lower nut (lower arrow) and disconnect thelink assembly and bracket from the arm

dust boot. If the boot does become damaged(and you’re refitting the same control arm andballjoint), be sure to fit a new boot.13 Unscrew the nut which secures the outercontrol arm balljoint to the steering knuckle(see illustration) and detach the balljoint studfrom the knuckle (see illustration). Ideally youshould use a purpose-made balljointseparator tool for this job. Using a hammer isOK if you’re going to fit new parts anyway, butis not recommended if you’re planning to re-use parts.14 Remove the control arm.

15 If you’re renewing the control arm, you’llhave to fit a new bush (see above). The oldbush can’t be removed re-used in anothercontrol arm.16 Refitting is the reverse of removal. Be sureto use new self-locking nuts on the balljointstuds and tighten them, and the bush bracketbolts, to the torques listed in this Chapter’sSpecifications.17 When you’re finished, have the frontwheel alignment checked by a dealer servicedepartment or qualified garage.

4 Control and thrust arms (5-Series) - inspection, removaland refitting and bush renewal

3Inspection1 Inspect the thrust arm rubber bush (seeillustration 4.6b). If the bush is cracked, tornor otherwise deteriorated, renew it. Thecontrol arm bush can’t be inspected until thecontrol arm is removed.2 Raise the vehicle and place it securely onaxle stands.3 To inspect the control arm and thrust armballjoints for wear, grip the top and bottom ofeach balljoint with a large pair of water pump(“parrot jaw”) pliers, and try to squeeze them.Alternatively, use a lever or large screwdriverto move them up and down. If there’s any freeplay, renew the control arm or thrust arm. Theballjoints can’t be renewed separately.

RemovalNote: If a balljoint is worn or damaged, theonly way to renew it is to renew the controlarm or thrust arm. If you’re fitting a newcontrol arm or thrust arm, a new bush mustalso be fitted. The old bush can’t be removedfrom the old control arm or thrust arm and re-used in the new arm.4 Loosen the wheel bolts, raise the vehicleand support it securely on axle stands.Remove the wheel.5 If you’re removing the control arm, removethe three bolts from the steering arm (seeillustration) and separate the strut assemblyfrom the arm.6 Remove the nut and the through-bolt thatsecure the control arm or thrust arm rearmounting (see illustrations).7 Remove the nut from the balljoint (seeillustration). Support the steering arm andseparate the balljoint from the steering arm(see illustrations). Ideally you should use apurpose-made balljoint separator tool for thisjob. Using a hammer is OK if you’re going tofit new parts anyway, but is not recommendedif you’re planning to re-use parts.


4.5 If you’re removing the control arm,remove the three bolts (arrowed) from the

steering arm, and separate the strutassembly from the arm

3.13b . . . give the steering knuckle a fewsharp knocks with a hammer to releasethe balljoint stud from the strut housing,

and remove the control arm

3.13a Remove the self-locking nut fromthe balljoint stud which attaches the outer

end of the control arm to the steeringknuckle. If you don’t have a balljoint

separator tool . . .

4.7b You can separate the thrust armballjoint from the steering arm with a

puller . . .

4.6a If you’re removing the control arm,remove the self-locking nut and the

through-bolt (arrowed) that attach theinner end of the arm to the vehicle

4.7a Remove the self-locking nut (controlarm nut, left arrow; thrust arm nut, right

arrow) from the balljoint, then support thesteering arm, and press or knock the

balljoint out of the steering arm

4.6b If you’re removing the thrust arm,remove the nut and bolt (arrowed) that

secure the rear end of the arm

10

Bush inspection and renewal8 If the bush is cracked, torn or otherwisedeteriorated, take the arm to a BMW dealerservice department or an engineering works,and have it pressed out and a new bushpressed in. Bushes should always be renewedin pairs (a new bush should be fitted in eacharm, and both bushes should have the samemanufacturer markings). If you’re fitting a newthrust arm bush, make sure it’s correctlyorientated (see illustration).

Refitting9 Refitting is the reverse of removal. Be sureto use new self-locking nuts on the balljointstud nut and the through-bolt. Don’t forget torefit the washers on both sides of the through-bolt. If you’re refitting the control arm, be sureto use thread-locking compound on thesteering arm mounting bolts. Don’t tighten thethrough-bolt to the final torque yet. Note:Thrust arms are marked “L” for the left side,and “R” for the right side. Be sure to check themarking before fitting a new arm.10 Support the control arm with a trolleyjack, and raise it to simulate normal rideheight, then tighten the through-bolt to thetorque listed in this Chapter’s Specifications.

Refit the wheel and tighten the wheel bolts tothe torque listed in the Chapter 1 Specifi-cations.11 Have the front end alignment checked ata dealer service department or qualifiedgarage.

5 Front strut assembly -removal and refitting 3

RemovalNote: Although strut assemblies don’t alwaysfail or wear out simultaneously, renew both leftand right struts at the same time, to preventhandling peculiarities or abnormal ride quality.1 Loosen but do not remove the front wheelbolts.2 Raise the front of the vehicle and support iton axle stands.3 Remove the front wheel.4 Detach all brake hoses and electrical wiresattached to the strut housing.5 Disconnect the electrical connections forthe ABS system, if applicable.6 If you’re removing the left strut, disconnect

the electrical connector for the brake padwear sensor.7 Remove the bolt securing the ABS wheelsensor, if applicable. Remove the brake disc(see Chapter 9).8 Remove the brake splash shield (seeillustration).9 On 3-Series models, disconnect the anti-roll bar from its connecting link (see Sec-tion 2). On 5-Series models, disconnect theanti-roll bar link from the strut housing (seeSection 2).10 On 3-Series models, disconnect thecontrol arm balljoint from the steering knuckle(see Section 3) and the track rod end from thesteering arm (see Section 17).11 On 5-Series models, disconnect the boltsthat attach the steering arm to the struthousing (see illustration 4.5).12 Pull out the lower end of the strut housingfar enough to clear the end of the control arm(3-Series) or the steering arm (5-Series).13 Support the weight of the strut andremove the three mounting nuts at the top ofthe strut, located inside the enginecompartment (see illustration) and removethe strut.14 Remove the strut assembly. If a newshock absorber (strut cartridge) is being fitted,see Section 6.

Refitting15 Refitting is the reverse of removal. On 3-Series models, be sure to use new self-locking nuts on the control arm balljoint, thetrack rod end balljoint and the strut uppermountings. On 5-Series models, make surethe tang in the steering arm is mated with thenotch in the strut housing (see illustration).BMW recommends using a thread-lockingcompound on the steering arm mountingbolts. On all models, tighten the fasteners tothe torques listed in this Chapter’s Specifi-cations.16 When you’re done, drive the vehicle to adealer service department or qualified garageand have the wheel alignment checked, and ifnecessary, adjusted.


5.15 On 5-Series models, make sure thetang in the steering arm is mated with the

notch in the strut housing (arrowed)

5.13 Support the weight of the strut andremove the three mounting nuts (arrowed)

at the top of the strut (5-Series shown, 3-Series similar)

5.8 To remove the brake splash shield,remove these three bolts (arrowed)

4.8 Correct orientation of the bush for the5-Series thrust arm. The arrow on the

rubber bush is aligned with the mark onthe arm, and the centre of the bush is

concentric with the bore

4.7c . . . but you may have to use ahammer to knock the control arm balljointstud loose from the steering arm, becausethere’s no room to use a puller. A purpose-

made balljoint separator tool would bebetter

6 Strut or shock absorber/coilspring - renewal 4

Note: This section applies to all front strutassemblies and, on 5-Series models, the rearcoil-over shock absorber assemblies.1 If the struts, shock absorbers or coil springsexhibit the telltale signs of wear (leaking fluid,loss of damping capability, chipped, saggingor cracked coil springs) explore all optionsbefore beginning any work. Strut or shockabsorber assemblies complete with springsmay be available on an exchange basis, whicheliminates much time and work. Whicheverroute you choose to take, check on the costand availability of parts before dismantling thevehicle.

Warning: Dismantling a strut orcoil-over shock absorberassembly is a potentiallydangerous undertaking, and

utmost attention must be directed to thejob, or serious injury may result. Use only ahigh-quality spring compressor, andcarefully follow the manufacturer’sinstructions supplied with the tool. Afterremoving the coil spring from the strutassembly, set it aside in a safe, isolatedarea.2 Remove the strut or shock absorberassembly (see Section 5 or 11). Mount theassembly in a vice. Line the vice jaws withwood or rags to prevent damage to the unit,and don’t tighten the vice excessively.3 Following the tool manufacturer’sinstructions, fit the spring compressor (thesecan be obtained at most car accessory shops,or it may be possible to hire one) on thespring, and compress it sufficiently to relieveall pressure from the suspension support (seeillustration). This can be verified by wigglingthe spring.4 Prise the protective cap off the damper rodself-locking nut. Loosen the nut (seeillustration) with a spanner while holding the

damper rod stationary with another spanneror an Allen key.5 Remove the nut, the strut bearing, theinsulator and the large washer. Check thebearing for smooth operation. If it doesn’t turnsmoothly, renew it. Check the rubber insulatorfor cracking and general deterioration. If thereis any separation of the rubber, renew theinsulator.6 Lift off the spring retainer and the rubberring at the top of the spring. Check the rubberring for cracking and hardness. Renew it ifnecessary.7 Carefully lift the compressed spring fromthe assembly and set it in a safe place, suchas a steel cabinet.

Warning: Never place your headnear the end of the spring!

8 Slide the protective tube and rubberbumper off the damper rod. If either isdamaged or worn, renew it.9 If you’re working on a front strut, loosenand remove the threaded collar (seeillustration) and pull the old strut cartridgefrom the strut housing. Pour the old oil fromthe strut housing.10 On all struts except gas-charged units, fillthe strut housing with 20 to 25 cc (3-Series),42 to 47 cc (518i and 520i 5-Series models) or20 to 25 cc (all other 5-Series models) of

engine oil (the oil helps cool the shockabsorber by transferring heat to the struthousing). Note: It doesn’t matter whatviscosity or grade of engine oil is used.11 Refitting is otherwise the reverse ofremoval. Tighten the threaded collar to thetorque listed in this Chapter’s Specifications.Make sure you align the end of the coil springwith the shoulder of the rubber ring and withthe spring retainer (see illustration). Tightenthe damper rod nut to the torque listed in thisChapter’s Specifications. 12 Refit the strut or shock absorberassembly (see Section 5 or 11).

7 Balljoints - check and renewal 3CheckNote: On 3-Series models, there are twoballjoints on each control arm - one betweenthe middle of the arm and the subframe, andthe other between the outer end of the armand the steering knuckle. On 5-Series models,there are balljoints on the outer ends of thecontrol arm and the thrust arm.1 Raise the vehicle and support it securely onaxle stands.2 Visually inspect the rubber boot betweenthe balljoint and the subframe or steeringknuckle, etc for cuts, tears or leaking grease.If you note any of these conditions, renew thecontrol arm or thrust arm - the balljoints arenot available separately.3 Place a large lever under the balljoint, andtry to push the balljoint up. Next, position thelever between the arm and the subframe orbetween the arm and steering knuckle. If youcan see or feel any movement during eithercheck, a worn balljoint is indicated.4 Have an assistant grasp the tyre at the topand bottom, and shake the top of the tyre withan in-and-out motion. Touch the balljoint studnut. If any looseness is felt, suspect a wornballjoint stud or a widened hole in thesubframe or steering knuckle. If the latter


6.4 Prise the protective cap off thedamper rod nut, and remove the large nut

(arrowed) - to prevent the damper rod fromturning, place an Allen key in the end of

the shaft

6.3 Following the tool manufacturer’sinstructions, fit the spring compressor tothe spring, and compress it sufficiently torelieve all pressure from the suspension

support

6.11 Make sure you align the end of thecoil spring with the shoulder of the rubber

ring, and with the spring retainer

6.9 Loosen and remove the threadedcollar, and pull the old strut cartridge from

the strut housing - on all struts exceptgas-charged units, pour the old oil fromthe strut housing. (Spring should have

been removed first!)

10

problem exists, a new subframe or steeringarm (5-Series) or steering knuckle (3-Series),which is integral with the strut housing, shouldbe fitted as well as the new balljoint.

RenewalNote: None of these balljoints can be servicedor renewed individually. If one of them is worn,a complete new arm must be fitted.

8 Front hub and wheel bearingassembly - removal and refitting

3Note: Removing the front hub/bearingassembly renders it unfit for re-use. A newassembly will be required for refitting.

Removal1 Loosen the wheel bolts, then raise the frontof the vehicle, and support it securely on axlestands. Remove the wheel bolts and thewheel.2 Using a hammer and chisel, remove thedust cap from the centre of the wheel hub(see illustration).3 Unstake the hub nut (see illustration).4 Refit the wheel and lower the vehicle to theground. Loosen, but do not remove, the hubnut.

Warning: Always loosen andtighten the hub nut with thevehicle on the ground. The

leverage needed to loosen the nut (whichis very tight) could topple the vehicle off alift or an axle stand.5 Raise the front of the vehicle, support itsecurely on axle stands, and remove the frontwheel again.6 Remove the front brake caliper andmounting bracket (see Chapter 9). There is noneed to disconnect the brake hose. Hang thecaliper out of the way with a piece of wire.7 Remove the brake disc (see Chapter 9).8 Remove the hub nut, and pull the hub andbearing assembly off the stub axle. You mayhave to tap it off if it’s stuck (see illustration).If the inner race of the bearing remains on thestub axle (it probably will), remove the dustshield (rubber boot) behind the bearing, anduse a puller to remove the inner race (seeillustration).

Refitting9 Fit a new dust shield.10 Push the new hub and bearing onto thestub axle. If it’s necessary to use force, pressor drive only against the bearing inner race(see illustration).11 Fit a new hub nut, and tighten it finger-tight at this stage.12 Refit the brake disc, its countersunkretaining screw, and the brake caliper (seeChapter 9).13 Refit the wheel, and lower the vehicle tothe ground.14 Tighten the hub nut to the torque listed in

this Chapter’s Specifications. Again, makesure you do this with the vehicle on theground, not up on axle stands.15 Raise the front of the vehicle and place itsecurely on axle stands. Remove the wheel.16 Stake the collar of the nut into the grooveof the spindle.17 Apply suitable sealant to a new greasecap, and fit the cap by driving it into placewith a soft-faced mallet.18 Refit the wheel and wheel bolts. Lower thevehicle to the ground, and tighten the wheelbolts to the torque listed in the Chapter 1Specifications.

9 Rear shock absorbers (3-Series) - removal and refitting

3RemovalNote: Although shock absorbers don’t alwayswear out simultaneously, renew both left andright shock absorbers at the same time, toprevent handling peculiarities or abnormal ridequality.1 Chock the front wheels.2 Raise the rear of the vehicle, and support itsecurely on axle stands. Support the trailingarm with a trolley jack. Place a block of woodon the jack head to serve as a cushion.3 Remove the shock absorber lowermounting bolt (see illustration).


9.3 Remove the shock absorber lowermounting bolt (arrowed)

8.10 Use a large socket or a suitable pieceof pipe to drive against the inner race of

the new bearing

8.8b If the inner race of the bearing sticksto the stub axle, use a puller to get it off

8.8a If the hub sticks, knock it loose with ahammer

8.3 Using a chisel, knock out the stakedportion of the hub nut

8.2 Using a hammer and chisel, knock outthe dust cap in the centre of the hub

4 On some models, working inside the boot,you can remove the trim to access the uppermounting nuts; on later models, you’ll have toremove the rear seat back to get at the uppermounting nuts. On Touring (Estate) models,remove the side backrest and rear seat beltreels, and unscrew the centring shell on thewheel arch. On Convertibles, simply removethe top from the recessed well behind thepassenger compartment, and remove thesmall rubber access cover. As you remove themounting nuts (see illustration), have anassistant support the shock absorber frombelow so it doesn’t fall out.5 Look for oil leaking past the seal in the topof the shock absorber body. Inspect therubber bushings in the shock absorber eye. Ifthey’re cracked, dried or torn, renew them. Totest the shock absorber, grasp the shockabsorber body firmly with one hand, and pushthe damper rod in and out with the other. Thestrokes should be smooth and firm. If the rodgoes in and out too easily, or unevenly, theshock absorber is defective and must berenewed.

Refitting6 Fit the shock absorbers in the reverse orderof removal, but don’t tighten the mountingbolts and nuts yet.7 Bounce the rear of the vehicle a couple oftimes to settle the bushings, then tighten thenuts and bolts to the torque values listed inthis Chapter’s Specifications.

10 Rear coil springs (3-Series) -removal and refitting 4

Note: Although coil springs don’t always wearout simultaneously, renew both left and rightsprings at the same time, to prevent handlingpeculiarities or abnormal ride quality.

Removal1 Loosen the wheel bolts. Chock the frontwheels, then raise the rear of the vehicle and

support it securely on axle stands. Make surethe stands don’t interfere with the rearsuspension when it’s lowered and raisedduring this procedure. Remove the wheels.2 Disconnect the mountings and bracketswhich support the rear portion of the exhaustsystem, and temporarily lower the exhaustsystem (see Chapter 4). Lower the exhaustsystem only enough to lower the suspensionand remove the springs. Suspend the exhaustwith a piece of wire.3 Support the differential with a trolley jack,then remove the differential rear mountingbolt. Push the differential down, and wedge itinto this lowered position with a block ofwood. This reduces the drive angle,preventing damage to the CV joints when thetrailing arms are lowered to remove thesprings.4 Place a trolley jack under the trailing arm.5 If the vehicle has a rear anti-roll bar,disconnect the bar from its connecting links,or disconnect the links from the trailing arms(see Section 12).6 Loop a chain through the coil spring, andbolt the chain together, to prevent the coilspring from popping out when the trailing armis lowered. Be sure to leave enough slack inthe chain to allow the spring to extendcompletely.7 Disconnect the shock absorber lowermounting bolt (see Section 9), carefully lowerthe trailing arm and remove the coil spring.

Refitting8 Refitting is the reverse of removal. As thetrailing arm is raised back up, make sure thespring seats properly.

11 Rear shock absorber/coilspring assembly (5-Series) -removal and refitting 4

RemovalNote: Although shock absorbers don’t alwayswear out simultaneously, renew both left andright shock absorbers at the same time, toprevent handling peculiarities or abnormal ridequality.

1 Loosen the wheel bolts, then chock thefront wheels. Raise the vehicle and support itsecurely on axle stands. Remove the wheels.2 Remove the shock absorber lowermounting bolt (see illustration).3 On early models, peel back the trim insidethe luggage compartment far enough toaccess the upper mounting nuts. To get at theupper mounting nuts on later models, firstremove the rear seat cushion (see Chap-ter 11), then remove the two bolts holding therear seat backrest, and remove the backrest.Support the trailing arm with a jack, andremove the upper mounting nuts (seeillustration). Lower the jack, and remove theshock absorber and the gasket. To separatethe shock absorber and spring, refer toSection 6.

Refitting4 Refitting is the reverse of removal. Don’tforget to fit the gasket between the upper endof the shock absorber and the body. Tightenthe upper nuts to the torque listed in thisChapter’s Specifications. Don’t tighten thelower bolt until the vehicle is lowered.5 Lower the vehicle, and with it sitting at thenormal ride height, tighten the lower bolt tothe torque listed in this Chapter’s Specifi-cations.

12 Rear anti-roll bar - removal and refitting 2

RemovalNote: The rear anti-roll bar is mountedbasically the same way on all models. Followthese general removal and refittingprocedures, keeping in mind any variations.1 Chock the front wheels, then raise the rearof the vehicle and support it securely on axlestands.2 Remove the anti-roll bar bracket bolts ornuts (see illustration).3 Disconnect the anti-roll bar from the link ateach end of the bar (see illustrations) anddetach the anti-roll bar.


11.3 Shock absorber upper mounting nuts(arrowed) on a later (E34) 5-Series model

11.2 Remove the shock absorber lowermounting bolt (arrowed)

9.4 Shock absorber upper mounting nuts(arrowed) - late-model convertible shown.

On other early models, upper nuts areaccessible from the luggage compartment;on later models, they’re behind the back of

the rear seat, up under the parcel shelf

10

4 Inspect and, if necessary, renew any wornor defective bolts, washers, bushes or links.

Refitting5 Refitting is the reverse of removal. Tightenall fasteners securely.

13 Rear trailing arms (3-Series)- removal and refitting 3

Removal1 Loosen the wheel bolts, then chock thefront wheels. Raise the rear of the vehicle, andsupport it securely on axle stands. Removethe wheel(s).2 Remove the driveshaft (see Chapter 8), ordisconnect it from the final drive outputflange.3 Disconnect the rear brake hose from themetal brake line at the bracket on the trailingarm (see illustration). Note: For informationon disconnecting brake hose-to-metal lineconnections, see Chapter 9. Plug the line andhose, to prevent dirt ingress and loss of brakefluid.4 Disconnect the handbrake cable (seeChapter 9).5 Disconnect the lower end of the shock

absorber from the trailing arm (see Section 9),and lower the trailing arm.6 Remove the trailing arm pivot bolts (seeillustration) and remove the trailing arm.7 Inspect the pivot bolt bushes. If they’recracked, dried out or torn, take the trailingarm to an engineering works and have themnew ones fitted. Each bush has a largerdiameter shoulder on one end. Make sure thislarger diameter shoulder on each bush facesaway from the trailing arm, ie the inner bushshoulder faces the centre of the vehicle, andthe outer bush shoulder faces away from thevehicle.

Refitting8 Refitting is the reverse of removal. Supportthe trailing arm with a trolley jack, and raise itto simulate normal ride height, then tightenthe nuts and bolts to the torque listed in thisChapter’s Specifications. Be sure to bleed thebrakes as described in Chapter 9.

14 Rear trailing arms (5-Series)- removal and refitting 3

Removal1 Loosen the wheel bolts, then chock thefront wheels. Raise the rear of the vehicle andsupport it securely on axle stands. Removethe wheel(s).

2 Remove the driveshaft (see Chapter 8).3 Disconnect the rear brake hose from themetal brake line at the bracket on the trailingarm (see illustration). Note: For informationon disconnecting brake hose-to-metal lineconnections, see Chapter 9. Plug the line andhose, to prevent dirt ingress and loss of brakefluid.4 Disconnect the handbrake cable from thehandbrake actuator, and unclip the handbrakecable from the trailing arm (see Chapter 9).5 Remove the ABS wheel sensor (ifapplicable) from the trailing arm, and unclipthe sensor wire harness from the arm.Position the sensor aside so it won’t bedamaged during removal of the trailing arm.6 If you’re removing the right trailing arm,unplug the connector for the brake pad wearsensor, if applicable.7 Disconnect the rear anti-roll bar from thetrailing arm (see Section 12).8 On 1983 and later models, remove one ofthe rear axle carrier bolts (see illustration).9 Disconnect the shock absorber lowermounting bolt (see Section 11).10 Remove the two trailing arm pivot boltsand nuts, and remove the trailing arm from thevehicle.11 Inspect the pivot bolt bushes. If they’recracked, dried out or torn, take the trailingarm to an engineering works, and have newones fitted. The bush inner sleeve is longer onone side. Make sure the bushes are fitted with


14.3 Disconnect the brake hose (leftarrow) from the fitting on the metal brake

line (right arrow) at this bracket

13.6 Nut (arrowed) for the outer pivot bolt

13.3 Disconnect the rear brake hose(middle arrow) from the metal brake linefitting (right arrow) at this bracket on thetrailing arm, then plug the line and hose

immediately; the other arrow points to thenut for the inner pivot bolt

12.3b Bolt (arrowed) connecting rear anti-roll bar link to trailing arm (5-Series)

12.3a A nut and bolt (arrowed) connecteach rear anti-roll bar link to the rear

trailing arms (3-Series)

12.2 Rear anti-roll bar bracket bolt(arrowed) (3-Series)

the longer side of the sleeve facing towardsthe centre of the vehicle.

Refitting12 Refitting is the reverse of removal. Refitthe inner pivot bolt first. Don’t fully tighten thenuts on the pivot bolts or the shock absorberyet.13 Bleed the brakes as described in Chap-ter 9.14 Support the trailing arm with a trolley jack,and raise it to simulate normal ride height.Tighten the bolts and nuts to the torqueslisted in this Chapter’s Specifications.

15 Rear wheel bearings -renewal 4

3-Series models1 Loosen the driveshaft nut and the rearwheel bolts, then chock the front wheels.Raise the rear of the vehicle and place itsecurely on axle stands. Remove the rearwheel. Note: Depending on the type of rearwheel, it may be necessary to remove thewheel first, remove the hubcap, then refit thewheel and loosen the driveshaft nut.2 Remove the driveshaft (see Chapter 8).

3 On models with rear brake drums, removethe drum. On models with rear disc brakes,remove the brake caliper and mountingbracket. Don’t disconnect the hose. Hang thecaliper out of the way with a piece of wire.Remove the brake disc (see Chapter 9).Working from behind, drive the wheel hub outof the wheel bearing with a large socket or apiece of pipe.

4 Remove the large circlip (see illustration)that holds the wheel bearing in the wheelbearing housing, then drive out the bearingwith a large socket or piece of pipe.5 Refitting is basically the reverse of removal,bearing in mind the following points:a) Be extremely careful where you place the

socket or piece of pipe when you drivethe new bearing into the housing. Itshould be butted up against the outerrace of the bearing. Driving in the newbearing using the inner race will ruin thebearing.

b) Refit the wheel and lower the vehicle tothe ground before attempting to tightenthe driveshaft nut to the torque listed inthe Chapter 8 Specifications.

5-Series models6 Chock the front wheels, then raise the rearof the vehicle and support it securely on axlestands. Disconnect the outer CV joint from thedrive flange (see Chapter 8). Support the outerend of the driveshaft with a piece of wire -don’t let it hang, as this could damage theinner CV joint.7 Prise out the lockplate that secures thedrive flange nut (see illustration). Onceyou’ve prised out an edge of the lockplate,pull it out with a pair of needle-nose pliers.8 Lower the vehicle and unscrew the driveflange nut, but don’t remove it yet. You’ll needa long bar (see illustration).

Warning: Don’t attempt to loosenthis nut with the vehicle on axlestands. The force required toloosen the nut could topple thevehicle from the stands.

9 Loosen the rear wheel bolts, raise the rearof the vehicle again, place it securely on axlestands and remove the wheel.10 Remove the brake caliper and the brakedisc (see Chapter 9). Hang the caliper out ofthe way with a piece of wire.11 Remove the drive flange nut. Using asuitable puller, remove the drive flange (seeillustration).12 Using a soft-faced hammer, drive the stubaxle out of the bearing (see illustration). If thebearing inner race comes off with the stub


15.7 Prise out the lockplate that securesthe drive flange nut - once you’ve prisedout an edge of the lockplate, pull it out

with a pair of needle-nose pliers

15.4 An exploded view of the 3-Series rearwheel bearing assembly

14.8 On 1983 and later models, removeone of these trailing arm-to-axle carrierbolts (it doesn’t matter which one youremove - one attaches the link to the

trailing arm, and the other attaches the linkto the axle carrier)

15.12 Using a soft-faced hammer, drivethe stub axle out of the bearing

15.11 Remove the drive flange with apuller

15.8 Lower the vehicle and loosen thedrive flange nut

10

If the bearing inner racesticks to the hub (it probablywill), use a puller to removethe race from the hub.

axle (it probably will), use a puller to removethe race from the stub axle. If you can’t getthe race off with a puller, take the stub axle toan engineering works and have it pressed off.13 Remove the large circlip that retains thebearing in the bearing housing (seeillustration), then drive the bearing out of thebearing housing with a large socket or asuitable piece of pipe (see illustration).14 Refitting is basically a reversal of removal,bearing in mind the following points:a) Fit the new bearing using a large socket

or a suitable piece of pipe, with anoutside diameter the same diameter asthe outer race (see illustration). Don’tapply force to the inner race. Make surethe bearing is fully seated against theback of the bore. Refit the circlip, makingsure it’s fully seated into its groove.

b) BMW dealers use special tools (Part Nos.23 1 1300, 33 4 080 and 33 4 020) to pullthe stub axle into the bearing, becausethe smooth portion between the splinedportion of the stub axle and the flange is apress-fit, and knocks out the wheelbearing inner race during refitting of thestub axle. However, you can refit the stubaxle without these tools, using the oldinner race and a piece of pipe 13 mmlong by 38 mm inside diameter (see

illustration). First, insert the stub axlethrough the new bearing until thethreaded portion protrudes from the innerrace. Refit the nut and tighten it until thesplined portion of the stub axle shaftbottoms against the nut. You’ll need tohold the stub axle flange with a lever or alarge screwdriver while tightening the nut(see illustration). Remove the nut, refityour piece of pipe, centred on the innerrace and refit the nut (see illustration).Tighten the nut again until it bottomsagainst the splines. Remove the nut, refitthe old inner race, refit the nut and tightenit once more until it bottoms against thesplines. Remove the nut, remove the oldinner race, refit your piece of pipe, refitthe old inner race, refit the nut and tightenit until it bottoms against the splines.Remove the nut, the old race and thepipe. Refit the drive flange, refit the nutand tighten it securely, but don’t attemptto tighten it to the final torque until thevehicle is lowered to the ground.

c) Refit the wheel and lower the vehicle tothe ground before tightening the stub axlenut to the torque listed in this Chapter’sSpecifications.

15 The remainder of refitting is the reverse ofremoval.

16 Steering system - general information

On 3-Series models, the steering wheel andsteering column are connected to a rack-and-pinion steering gear (power-assisted whereapplicable) via a short universal joint shaft.When the steering wheel is turned, thesteering column and universal joint turn apinion gear shaft on top of the rack. Thepinion gear teeth mesh with the gear teeth ofthe rack, so the rack moves right or left in thehousing when the pinion is turned. Themovement of the rack is transmitted throughthe track rods and track rod ends to thesteering arms, which are an integral part ofthe strut housings.

On 5-Series models, the upper part of thesteering system is identical to a 3-Series.Instead of a rack-and-pinion set-up, however,these models use a power-assistedrecirculating ball steering box which steersthe front wheels via a steering linkageconsisting of a Pitman arm, an idler arm, acentre track rod, a pair of inner track rods,and two track rod ends.


15.14d When you refit the spacer, makesure it’s centred on the inner race of the

bearing before tightening the nut

15.14c Hold the stub axle flange with alarge lever while tightening the nut

15.14b You can fabricate your own spacertool from a piece of 13 mm long, 38 mm

inside diameter pipe (left); you’ll also needto use the old inner race (right)

15.14a To refit the new bearing, use alarge socket or a piece of pipe with an

outside diameter the same diameter as theouter race of the bearing - don’t apply

force to the inner race - and make sure thebearing is fully seated against the back of

its bore

15.13b . . . then drive the bearing out ofthe housing with a large socket or a

suitable piece of pipe

15.13a Remove the large circlip thatretains the bearing in the housing . . .

Where power-assistance is fitted, hydraulicpressure (provided by an engine-driven pump)delivers power steering fluid to the rack-and-pinion steering gear or the recirculating-ballsteering box - this enhances steeringresponse and reduces steering effort.

Aside from maintaining the proper level ofpower steering fluid in the system andchecking the tension of the drivebelt (seeChapter 1, where applicable), the steeringsystem requires no maintenance. However,on high-mileage vehicles, the track rod endballjoints, the universal joints on either end ofthe universal joint shaft, and the rubbercoupling between the steering column and theuniversal joint shaft will wear, developexcessive play, and cause the steering to feelsomewhat loose. At this point, you’ll have torenew these items; they can’t be serviced.

Before you conclude that the steeringsystem needs work, however, always checkthe tyres (see Section 25) and tyre pressures(see Chapter 1). Also inspect the bearings inthe strut upper mounts (see Section 5), thefront hub bearings (see Section 8) and othersuspension parts, which may also becontributing to an imprecise steering feel.

17 Track rod ends - removal and refitting 4

1 Loosen but do not remove the wheel bolts,then raise the front of the vehicle and secure iton axle stands. Remove the front wheel.

3-Series models2 Loosen the nut on the track rod balljointstud, and free the balljoint stud from thesteering arm using a balljoint separator. In theabsence of a separator tool, try giving thesteering arm a few light blows with a hammer(see illustration). Remove the nut, andseparate the balljoint stud from the steeringarm.

3 Loosen the clamp bolt that locks the trackrod end to the inner track rod. Measure thelength of the track rod end, or paint analignment mark on the threads to ensure thetrack rod end is refitted in the same position(see illustration). Unscrew the track rod endfrom the inner track rod.4 Refitting is the reverse of removal. Makesure the mark you made on the threads of thetrack rod end is aligned correctly, ifapplicable. If you measured the track rod end,make sure it is refitted to the same distance.5 Have the toe-in checked and, if necessary,adjusted at a dealer service department orqualified garage.

5-Series models6 Measure the length of the track rod andrecord your measurement, or paint analignment mark on the threads to ensure thetrack rod end is refitted in the same position(see illustration). Loosen the clamp bolt.7 Use a balljoint separator or a puller toseparate the track rod end from the steeringarm (see illustration).8 Unscrew the track rod end.9 Refitting is the reverse of removal. Makesure you align the paint mark made on thethreads of the track rod end, if applicable. Ifyou measured the track rod end, make sure itis refitted to the same distance.10 Have the toe-in checked and, ifnecessary, adjusted at a dealer servicedepartment or qualified garage.

18 Steering gear boots (3-Series) - renewal 4

1 Remove the track rod ends (see Sec-tion 17).2 Cut the boot clamps at both ends of the oldboots, and slide off the boots.3 While the boots are removed, inspect theseals in the end of the steering gear. If they’re

leaking, renew the steering gear (see Sec-tion 19).4 Slide the new boots into place and fit newboot clamps.5 Refit the track rod ends (see Section 17).

19 Rack-and-pinion steeringgear (3-Series) - removal and refitting

4Removal1 Loosen but do not remove the wheel bolts,raise the vehicle and support it securely onaxle stands. Remove the front wheels.2 Mark the lower universal joint on thesteering shaft and the pinion shaft, to ensureproper alignment when they’re reassembled.Remove the nut and bolt that attach the lowerend of the universal joint shaft to the steeringgear pinion shaft. Loosen the bolt and nut atthe upper end of the universal joint shaft. Slidethe universal joint shaft up a little, disengage itfrom the pinion shaft, and remove it. Inspectthe universal joints and the rubber couplingfor wear. If any of them are worn or defective,renew the universal joint shaft.3 On power steering models, using a large


17.6 Measure the length of the track rodand record your measurement, or paint analignment mark on the threads to ensurethe track rod end is refitted in the same

position, then loosen the clamp bolt(arrowed)

17.3 Loosen the clamp bolt (arrowed) thatlocks the track rod end to the inner track

rod. Paint an alignment mark on thethreads, to ensure the track rod end is

refitted in the same position, and unscrew the track rod end from the inner

track rod

17.2 Loosen the nut on the track rodballjoint stud. For preference use a

balljoint separator; otherwise, give thesteering arm a few light blows with ahammer to release the balljoint stud.

Remove the nut, and separate the balljointstud from the steering arm

17.7 Using a puller to separate the trackrod end from the steering arm

10

syringe or hand pump, empty the powersteering fluid reservoir.4 On power steering models, remove thebanjo bolts and disconnect the powersteering pressure and return lines from thesteering gear. Place a container under thelines to catch spilled fluid. Plug the lines toprevent excessive fluid loss andcontamination. Discard the sealing washers(new ones should be used whenreassembling).5 Disconnect the track rod ends from thesteering arms (see Section 17).6 Remove the nuts and bolts from thesteering gear mounting brackets (seeillustration). Discard the old nuts.7 Withdraw the assembly from beneath thevehicle. Take care not to damage the steeringgear boots.

Refitting8 Refitting is the reverse of removal. Makesure the marks you made on the loweruniversal joint and the pinion shaft are alignedbefore you tighten the clamping bolts for theupper and lower universal joints. Use newself-locking nuts on the steering rack

mounting bolts, and new sealing washers onthe hydraulic line fittings. Tighten themounting bolts, the track rod end nuts and theuniversal joint shaft clamping bolts to thetorque values listed in this Chapter’s Specifi-cations.9 Lower the vehicle to the ground.10 On power steering models, fill thereservoir with the recommended fluid (seeChapter 1) and bleed the power steeringsystem (see Section 23).11 It’s a good idea to have the front wheelalignment checked by a dealer servicedepartment or qualified garage.

20 Steering linkage (5-Series) -inspection, removal andrefitting

4Inspection1 Raise the vehicle and place it securely onaxle stands.2 Firmly grasp each front tyre at the top andbottom, then at the front and rear, and checkfor play in the steering linkage by rocking thetyre back and forth. There should be little orno play in any of the linkage balljoints. Inspectthe Pitman arm, the idler arm, the centre trackrod, the inner track rods, the track rod endsand the steering arms for any obviousdamage. Try forcing the linkage parts inopposite directions from one another. Thereshould be no play between any of them. If anyof the parts are bent or damaged in any way,or if any of the balljoints are worn, renew theparts concerned.

Removal3 Before dismantling the steering linkage,obtain a suitable balljoint separator. A two-jawpuller or a wedge-type tool will work (althoughthe wedge-type tends to tear the balljointboots). Sometimes, you can also jar a balljointtaper pin free from its eye by striking oppositesides of the eye simultaneously with two largehammers, but the space available to do this islimited, and the balljoint stud sometimes

sticks to the eye because of rust and dirt.There is also a risk of damaging thecomponent being struck.4 To remove the outer track rods, disconnectthe track rod ends from the steering arms (seeSection 17). Remove the nut that attaches theballjoint on the inner end of each outer trackrod to the centre track rod (see illustration).Using a balljoint separator, disconnect theouter track rods from the centre track rod. Ifyou’re renewing the balljoint at either end ofthe outer track rods, paint or scribe alignmentmarks on the threads to mark their respectivepositions as a guide to adjustment duringreassembly (see illustration 17.3).5 To remove the centre track rod, remove thenuts that attach the centre track rod balljointsto the Pitman arm and the idler arm, and use aballjoint separator to disconnect the balljointsfrom the two arms.6 To remove the Pitman arm, you’ll have toremove the steering box first (see Section 21).Look for match marks between the sectorshaft and arm. If there aren’t any, scribe amark across the bottom face of both parts.Remove the Pitman arm pinch-bolt and nut,then remove the arm with a puller.7 To unbolt the idler arm, first remove thesmall cover bolted to the top of the subframecrossmember. Put a spanner on the bolt, andremove the nut recessed into the underside ofthe subframe crossmember (see illustration).Check the idler arm rubber bush for wear. Ifit’s damaged or worn, renew it.8 Check each balljoint for excessive play orstiffness, and for split or deteriorated rubberdust boots. Renew all worn or damagedballjoints. The inner and outer track rod endson the outer track rods can be renewedindividually; if either balljoint on the centretrack rod is damaged or worn, you mustrenew the centre track rod.

Refitting9 Refitting is the reverse of the removalprocedure, but observe the following points:a) Realign the match marks on the Pitman

arm and the steering box sector shaftwhen reassembling them.

b) If you’re fitting new inner or outer trackrod ends on the outer track rods, positionthem so that the match marks madeduring dismantling are aligned, and makesure they are equally spaced on eachside.

c) Position the track rod end balljoint studson the outer track rods at an angle of 90°to each other.

d) Make sure the left and right outer trackrods are equal in length when they arefitted.

e) Tighten all retaining bolts to the torquevalues listed in this Chapter’s Specifi-cations.

f) When reassembly of the linkage iscomplete, have the front wheel alignmentchecked, and if necessary, adjusted.


20.7 To unbolt the idler arm from thesubframe crossmember, remove this nut

(arrowed)

20.4 To remove an outer track rod,remove this nut (arrowed) from the end ofthe centre track rod, and use a balljointseparator to separate the balljoint stud

from the centre track rod (if you’rerenewing the inner track rod end, mark the

threads with paint before loosening theclamp bolt and nut)

19.6 Rack-and-pinion steering gearmounting bolts (arrowed) - 3-Series

models - (self-locking nuts not visible inthis photo)

21 Steering box (5-Series) -removal and refitting 4

RemovalNote: If you find that the steering box isdefective, it is not recommended that youoverhaul it. Because of the special toolsneeded to do the job, it is best to let yourdealer service department overhaul it for you(otherwise, fit a new unit). Removal andrefitting the steering box is outlined here.1 On 5-Series E28 (“old-shape”) models,discharge the hydraulic system by depressingthe brake pedal about 20 times.2 Using a large syringe or hand pump, emptythe power steering fluid reservoir (see Chap-ter 1).3 Raise the front of the vehicle and support itsecurely on axle stands.4 Support the front of the engine with a trolleyjack. Place a block of wood between the jackhead and the sump to protect the sump fromdamage.5 Remove the pivot bolts from the inner endsof the front control arms (see Section 4).6 Remove the nuts from the left and rightengine mountings (see Chapter 2).7 Remove the mounting bolts (two on eachside on earlier models, three on each side onlater models) from the subframe crossmember(see illustration) and remove the subframe.8 Remove the nuts and bolts that secure theuniversal joint shaft to the steering box wormshaft. Slide the universal joint shaft up and offthe worm shaft. Inspect the universal jointshaft for wear. If it’s stiff or worn, renew it.9 Remove the banjo bolts, and disconnectthe hydraulic pressure line and the return linefrom the box (see illustration). Plug the endsof the lines to prevent fluid loss andcontamination. Discard the sealing washers -new ones should be used when reassembling.10 Remove the steering box retaining bolts(see illustrations) and remove the steeringbox.11 If it’s necessary to detach the Pitman armfrom the box sector shaft (to have the boxserviced or to switch the arm to a new or

rebuilt unit), make a match mark across thetwo for correct reassembly. Remove thePitman arm retaining nut and washer. Use apuller to withdraw the arm if necessary.

Refitting12 Refit the Pitman arm by aligning thematch marks made during removal, thentighten the nut to the torque listed in thisChapter’s Specifications.13 When fitted the Pitman arm must not haveany measurable endfloat within 100° from theneutral position. If play exists, have thefollowing parts checked:a) Sector shaft and bearings (for wear)b) Thrust washer and adjuster bolt head (for

wear)c) Ball nut and worm shaft (for wear)14 Refit the steering box. Align the mark onthe pinion gear shaft with the mark on theuniversal joint shaft, and tighten the steeringbox bolts to the torque listed in this Chapter’sSpecifications.15 The remainder of refitting is the reverse ofremoval. Be sure to use new self-locking nutson the universal joint shaft, the centre trackrod, the steering box and the crossmember.Also, use new sealing washers on thehydraulic line fittings.16 Refer to Chapter 1 and fill the power

steering reservoir with the recommendedfluid, then bleed the system as described inSection 23. Check for leakage from the linesand connections.

22 Power steering pump -removal and refitting 1

Removal1 Raise the vehicle and support it securely onaxle stands. Remove the engine undertray.2 On 5-Series E28 (“old-shape”) models,discharge the hydraulic system by depressingthe brake pedal about 20 times beforeloosening the hydraulic line fittings.3 Disconnect the fluid return hose, and drainthe power steering fluid from the reservoir intoa clean container. Disconnect the pressureline from the pump.4 If you need to remove the pulley from thepump, push on the power steering pumpdrivebelt by hand to increase the tension, andunscrew the pulley nuts or bolts.5 Loosen the power steering pump drivebelttensioner bolt, and remove the drivebelt (seeChapter 1).6 Remove the mounting bolts (seeillustrations) and detach the power steeringpump.


21.10a This bolt (arrowed) secures thesteering box to the subframe

crossmember. The nut, not visible in thisphoto, is accessed through a hole in the

crossmember (engine removed for clarity,left-hand-drive shown)

21.9 Disconnect the power steeringpressure line fitting (right arrow) and the

return line fitting (left arrow). Note that thereturn line fitting banjo bolt is larger thanthe bolt for the pressure line fitting (left-

hand-drive shown)

21.7 Subframe crossmember bolts(arrowed)

22.6a Typical 3-Series power steeringpump adjusting bolt (arrowed) . . .

21.10b This bolt (arrowed) attaches thesteering box to the body (the nut, not

visible in this photo, is on the front side ofthe steering box)

10

Refitting7 Refitting is the reverse of removal. Tightenthe nuts and bolts securely. Adjust thedrivebelt tension (see Chapter 1).8 Top-up the fluid level in the reservoir (seeChapter 1) and bleed the system (see Sec-tion 23).

23 Power steering system -bleeding 1

1 To bleed the power steering system, beginby checking the power steering fluid level andadding fluid if necessary (see Chapter 1).2 Raise and support the front of the vehicleon axle stands.3 Turn the steering wheel from lock-to-lockseveral times. Recheck the fluid level and topup if necessary.4 Start the engine and run it at 1000 rpm orless. Turn the steering wheel from lock-to-lock again (three or four times) and recheckthe fluid level one more time. Note: On 5-

Series E28 (“old-shape”) models, pump thebrake pedal five or six times before turning thesteering wheel. Once the fluid level remainsconstant, continue turning the wheel back andforth until no more bubbles appear in the fluidin the reservoir.5 Lower the vehicle to the ground. Run theengine and again turn the wheels from lock-to-lock several more times. Recheck the fluidlevel. Position the wheels straight-ahead.

24 Steering wheel - removal and refitting 1

Warning: If the vehicle isequipped with an airbag, do notattempt this procedure. Have itperformed by a dealer service

department or other qualified specialist, asthere is a risk of injury if the airbag isaccidentally triggered.



Removal


2 Using a small screwdriver, prise off theBMW emblem in the centre of the steeringwheel.3 Remove the steering wheel nut, and markthe relationship of the steering wheel hub tothe shaft (see illustration).4 On all 3-Series models, and on 1986 andlater 5-Series models, turn the ignition key tothe first position to unlock the ignition lock.5 Remove the steering wheel from the

steering shaft. If the wheel is difficult toremove from the shaft, use a steering wheelpuller to remove it - don’t hammer on theshaft.

Refitting6 Refitting is the reverse of removal. Be sureto align the match marks you made on thesteering wheel and the shaft. Tighten thesteering wheel nut to the torque listed in thisChapter’s Specifications.

25 Wheels and tyres - general information 1

Note: For more information on care andmaintenance of tyres, refer to Chapter 1.1 All vehicles covered by this manual areequipped with steel-belted radial tyres asoriginal equipment. Use of other types orsizes of tyres may affect the ride and handlingof the vehicle. Don’t mix different types orsizes of tyres, as the handling and brakingmay be seriously affected. It’s recommendedthat tyres be renewed in pairs on the sameaxle; if only one new tyre is being fitted, besure it’s the same size, structure and treaddesign as the other.2 Because tyre pressure has a substantialeffect on handling and wear, the pressure onall tyres should be checked at least once amonth or before any extended trips (seeChapter 1).3 Wheels must be renewed if they are bent,heavily dented, leak air, or are otherwisedamaged.4 Tyre and wheel balance is important in theoverall handling, braking and performance ofthe vehicle. Unbalanced wheels can adverselyaffect handling and ride characteristics, aswell as tyre life. Whenever a new tyre is fitted,the tyre and wheel should be balanced.


24.3 After removing the steering wheelnut, mark the relationship of the steeringwheel to the steering shaft (arrowed) to

ensure proper alignment duringreassembly

22.6c Typical 5-Series power steering pump mounting bolts(arrowed)

22.6b . . . and mounting nut and bolt (arrowed)

26 Wheel alignment - general information 4

Wheel alignment refers to the adjustmentsmade to the wheels so they are in properangular relationship to the suspension and theroad. Wheels that are out of proper alignmentnot only affect vehicle control, but alsoincrease tyre wear. The front end anglesnormally measured are camber, castor andtoe-in (see illustration). Front wheel toe-in isadjustable on all models; castor is notadjustable. Camber is only adjustable byreplacing the strut upper mount with a specialeccentric version. Toe-in is adjustable on therear wheels, but only by replacing the trailingarm outer bushings with special eccentricbushings.

Setting the proper wheel alignment is a veryexacting process, one in which complicatedand expensive equipment is necessary toperform the job properly. Because of this, youshould have a technician with the properequipment perform these tasks. We will,however, use this space to give you a basicidea of what is involved with wheel alignmentso you can better understand the process.

Toe-in is the “turning in” of the wheels. Thepurpose of a toe specification is to ensure

parallel rolling of the wheels. In a vehicle withzero toe-in, the distance between the frontedges of the wheels will be the same as thedistance between the rear edges of thewheels. The actual amount of toe-in isnormally very small. On the front end, toe-in iscontrolled by the track rod end position on thetrack rod. On the rear end, toe-in can only beadjusted by fitting special eccentric bushingsin the trailing arm outer mounting. Incorrecttoe-in will cause the tyres to wear improperlyby making them scrub against the roadsurface.

Camber is the “tilting” of the wheels fromvertical, when viewed from one end of thevehicle. When the wheels tilt out at the top, thecamber is said to be positive (+). When thewheels tilt in at the top the camber is negative (-). The amount of tilt is measured in degrees fromvertical, and this measurement is called thecamber angle. This angle affects the amount oftyre tread which contacts the road, andcompensates for changes in the suspensiongeometry when the vehicle is cornering ortravelling over an undulating surface.

Castor is the “tilting” of the front steeringaxis from the vertical. A tilt toward the rear atthe top is positive castor; a tilt toward thefront is negative castor. Castor is notadjustable on the vehicles covered by thismanual.


10

26.1 Wheel alignment details

1 A minus B = C (degrees camber)2 E minus F = toe-in

(expressed in inches or mm)3 G = toe-in (expressed in degrees)

11


These models feature an all-steel weldedconstruction, where the floorpan and bodycomponents are welded together andattached to separate front and rear subframeassemblies. Certain components areparticularly vulnerable to accident damage,and can be unbolted and repaired or renewed.Among these parts are the body mouldings,bumpers, bonnet, doors, tailgate, and allglass.

Only general body maintenance proceduresand body panel repair procedures within thescope of the do-it-yourselfer are included inthis Chapter.

2 Bodywork and underframe -maintenance 1

The general condition of a vehicle’sbodywork is the one thing that significantlyaffects its value. Maintenance is easy, butneeds to be regular. Neglect, particularly afterminor damage, can lead quickly to furtherdeterioration and costly repair bills. It isimportant also to keep watch on those partsof the vehicle not immediately visible, forinstance the underside, inside all the wheel

arches, and the lower part of the enginecompartment.

The basic maintenance routine for thebodywork is washing - preferably with a lot ofwater, from a hose. This will remove all theloose solids which may have stuck to thevehicle. It is important to flush these off insuch a way as to prevent grit from scratchingthe finish. The wheel arches and underframeneed washing in the same way, to remove anyaccumulated mud, which will retain moistureand tend to encourage rust. Paradoxicallyenough, the best time to clean the underframeand wheel arches is in wet weather, when themud is thoroughly wet and soft. In very wetweather, the underframe is usually cleaned oflarge accumulations automatically, and this isa good time for inspection.

Periodically, except on vehicles with a wax-based underbody protective coating, it is agood idea to have the whole of theunderframe of the vehicle steam-cleaned,engine compartment included, so that athorough inspection can be carried out to seewhat minor repairs and renovations arenecessary. Steam-cleaning is available atmany garages, and is necessary for theremoval of the accumulation of oily grime,which sometimes is allowed to become thickin certain areas. If steam-cleaning facilities arenot available, there are some excellent greasesolvents available which can be brush-applied; the dirt can then be simply hosed off.Note that these methods should not be used

on vehicles with wax-based underbodyprotective coating, or the coating will beremoved. Such vehicles should be inspectedannually, preferably just prior to Winter, whenthe underbody should be washed down, andany damage to the wax coating repaired.Ideally, a completely fresh coat should beapplied. It would also be worth consideringthe use of such wax-based protection forinjection into door panels, sills, box sections,etc, as an additional safeguard against rustdamage, where such protection is notprovided by the vehicle manufacturer.

After washing paintwork, wipe off with achamois leather to give an unspotted clearfinish. A coat of clear protective wax polish willgive added protection against chemicalpollutants in the air. If the paintwork sheen hasdulled or oxidised, use a cleaner/polishercombination to restore the brilliance of theshine. This requires a little effort, but suchdulling is usually caused because regularwashing has been neglected. Care needs to betaken with metallic paintwork, as special non-abrasive cleaner/polisher is required to avoiddamage to the finish. Always check that thedoor and ventilator opening drain holes andpipes are completely clear, so that water canbe drained out. Brightwork should be treated inthe same way as paintwork. Windscreens andwindows can be kept clear of the smeary filmwhich often appears, by the use of proprietaryglass cleaner. Never use any form of wax orother body or chromium polish on glass.

Chapter 11 Bodywork and fittings

Bodywork and underframe - maintenance . . . . . . . . . . . . . . . . . . . . 2Bodywork repair - major damage . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Bodywork repair - minor damage . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Bonnet - removal, refitting and adjustment . . . . . . . . . . . . . . . . . . . . 10Boot lid/tailgate - removal, refitting and adjustment . . . . . . . . . . . . . 14Bumpers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Door - removal, refitting and adjustment . . . . . . . . . . . . . . . . . . . . . 13Door trim panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 12Door window glass - removal and refitting . . . . . . . . . . . . . . . . . . . . 16Door window regulator - removal and refitting . . . . . . . . . . . . . . . . . 17Exterior mirror - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 18

Fixed glass - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Hinges and locks - maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Interior trim - maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Latch, lock cylinder and handles - removal, refitting and

adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Radiator grille - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 9Seat belt check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Seats - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Steering column shrouds - removal and refitting . . . . . . . . . . . . . . . 19Upholstery and carpets - maintenance . . . . . . . . . . . . . . . . . . . . . . . 4

11•1







Contents

3 Interior trim - maintenance 1Interior trim panels can be kept clean by

wiping with a damp cloth. If they do becomestained (which can be more apparent on light-coloured trim), use a little liquid detergent anda soft nail brush to scour the grime out of thegrain of the material. Do not forget to keep theheadlining clean in the same way. Aftercleaning, application of a high-quality rubberand vinyl protector will help prevent oxidationand cracks. The protector can also be appliedto weatherstrips, vacuum lines and rubberhoses, which often fail as a result of chemicaldegradation, and to the tyres.

4 Upholstery and carpets -maintenance 1

Mats and carpets should be brushed orvacuum-cleaned regularly, to keep them freeof grit. If they are badly stained, remove themfrom the vehicle for scrubbing or sponging,and make quite sure they are dry beforerefitting. Seats and interior trim panels can bekept clean by wiping with a damp cloth. If theydo become stained (which can be moreapparent on light-coloured upholstery), use alittle liquid detergent and a soft nail brush toscour the grime out of the grain of thematerial. Do not forget to keep the headliningclean in the same way as the upholstery.When using liquid cleaners inside the vehicle,do not over-wet the surfaces being cleaned.Excessive damp could get into the seams andpadded interior, causing stains, offensiveodours or even rot.

5 Bodywork repair - minor damage 3

Note: For more detailed information aboutbodywork repair, Haynes Publishing producea book by Lindsay Porter called “The CarBodywork Repair Manual”. This incorporatesinformation on such aspects as rust treatment,painting and glass-fibre repairs, as well asdetails on more ambitious repairs involvingwelding and panel beating.

Repairs of minor scratches inbodywork

If the scratch is very superficial, and doesnot penetrate to the metal of the bodywork,repair is very simple. Lightly rub the area ofthe scratch with a paintwork renovator, or avery fine cutting paste, to remove loose paintfrom the scratch, and to clear the surroundingbodywork of wax polish. Rinse the area withclean water.

Apply touch-up paint to the scratch using afine paint brush; continue to apply fine layersof paint until the surface of the paint in thescratch is level with the surroundingpaintwork. Allow the new paint at least twoweeks to harden, then blend it into thesurrounding paintwork by rubbing the scratcharea with a paintwork renovator or a very finecutting paste. Finally, apply wax polish.

Where the scratch has penetrated rightthrough to the metal of the bodywork, causingthe metal to rust, a different repair techniqueis required. Remove any loose rust from thebottom of the scratch with a penknife, thenapply rust-inhibiting paint to prevent theformation of rust in the future. Using a rubberor nylon applicator, fill the scratch withbodystopper paste. If required, this paste canbe mixed with cellulose thinners to provide avery thin paste which is ideal for filling narrowscratches. Before the stopper-paste in thescratch hardens, wrap a piece of smoothcotton rag around the top of a finger. Dip thefinger in cellulose thinners, and quickly sweepit across the surface of the stopper-paste inthe scratch; this will ensure that the surface ofthe stopper-paste is slightly hollowed. Thescratch can now be painted over as describedearlier in this Section.

Repairs of dents in bodyworkWhen deep denting of the vehicle’s

bodywork has taken place, the first task is topull the dent out, until the affected bodyworkalmost attains its original shape. There is littlepoint in trying to restore the original shapecompletely, as the metal in the damaged areawill have stretched on impact, and cannot bereshaped fully to its original contour. It isbetter to bring the level of the dent up to apoint which is about 3 mm below the level ofthe surrounding bodywork. In cases where thedent is very shallow anyway, it is not worthtrying to pull it out at all. If the underside of thedent is accessible, it can be hammered outgently from behind, using a mallet with awooden or plastic head. Whilst doing this,hold a suitable block of wood firmly againstthe outside of the panel, to absorb the impactfrom the hammer blows and thus prevent alarge area of the bodywork from being“belled-out”.

Should the dent be in a section of thebodywork which has a double skin, or someother factor making it inaccessible frombehind, a different technique is called for. Drillseveral small holes through the metal inside

the area - particularly in the deeper section.Then screw long self-tapping screws into theholes, just sufficiently for them to gain a goodpurchase in the metal. Now the dent can bepulled out by pulling on the protruding headsof the screws with a pair of pliers.

The next stage of the repair is the removalof the paint from the damaged area, and froman inch or so of the surrounding “sound”bodywork. This is accomplished most easilyby using a wire brush or abrasive pad on apower drill, although it can be done just aseffectively by hand, using sheets of abrasivepaper. To complete the preparation for filling,score the surface of the bare metal with ascrewdriver or the tang of a file, oralternatively, drill small holes in the affectedarea. This will provide a really good “key” forthe filler paste.

To complete the repair, see the Section onfilling and respraying.

Repairs of rust holes or gashesin bodywork

Remove all paint from the affected area,and from an inch or so of the surrounding“sound” bodywork, using an abrasive pad or awire brush on a power drill. If these are notavailable, a few sheets of abrasive paper willdo the job most effectively. With the paintremoved, you will be able to judge the severityof the corrosion, and therefore decidewhether to renew the whole panel (if this ispossible) or to repair the affected area. Newbody panels are not as expensive as mostpeople think, and it is often quicker and moresatisfactory to fit a new panel than to attemptto repair large areas of corrosion.

Remove all fittings from the affected area,except those which will act as a guide to theoriginal shape of the damaged bodywork (egheadlight shells etc). Then, using tin snips or ahacksaw blade, remove all loose metal andany other metal badly affected by corrosion.Hammer the edges of the hole inwards, inorder to create a slight depression for the fillerpaste.

Wire-brush the affected area to remove thepowdery rust from thesurface of the remaining metal. Paint theaffected area with rust-inhibiting paint, if theback of the rusted area is accessible, treatthis also.

Before filling can take place, it will benecessary to block the hole in some way. Thiscan be achieved by the use of aluminium orplastic mesh, or aluminium tape.

Aluminium or plastic mesh, or glass-fibrematting, is probably the best material to usefor a large hole. Cut a piece to theapproximate size and shape of the hole to befilled, then position it in the hole so that itsedges are below the level of the surroundingbodywork. It can be retained in position byseveral blobs of filler paste around itsperiphery.

Aluminium tape should be used for small orvery narrow holes. Pull a piece off the roll, trim

11•2 Bodywork and fittings

If the inside of the vehiclegets wet accidentally, it isworthwhile taking sometrouble to dry it out properly,

particularly where carpets are involved.Do not leave oil or electric heatersinside the vehicle for this purpose.

it to the approximate size and shape required,then pull off the backing paper (if used) andstick the tape over the hole; it can beoverlapped if the thickness of one piece isinsufficient. Burnish down the edges of thetape with the handle of a screwdriver orsimilar, to ensure that the tape is securelyattached to the metal underneath.

Bodywork repairs - filling andrespraying

Before using this Section, see the Sectionson dent, deep scratch, rust holes and gashrepairs.

Many types of bodyfiller are available, butgenerally speaking, those proprietary kitswhich contain a tin of filler paste and a tube ofresin hardener are best for this type of repair. Awide, flexible plastic or nylon applicator will befound invaluable for imparting a smooth andwell-contoured finish to the surface of the filler.

Mix up a little filler on a clean piece of cardor board - measure the hardener carefully(follow the maker’s instructions on the pack),otherwise the filler will set too rapidly or tooslowly. Using the applicator, apply the fillerpaste to the prepared area; draw theapplicator across the surface of the filler toachieve the correct contour and to level thesurface. As soon as a contour thatapproximates to the correct one is achieved,stop working the paste - if you carry on toolong, the paste will become sticky and beginto “pick-up” on the applicator. Continue toadd thin layers of filler paste at 20-minuteintervals, until the level of the filler is justproud of the surrounding bodywork.

Once the filler has hardened, the excesscan be removed using a metal plane or file.From then on, progressively-finer grades ofabrasive paper should be used, starting with a40-grade production paper, and finishing witha 400-grade wet-and-dry paper. Always wrapthe abrasive paper around a flat rubber, cork,or wooden block - otherwise the surface ofthe filler will not be completely flat. During thesmoothing of the filler surface, the wet-and-dry paper should be periodically rinsed inwater. This will ensure that a very smoothfinish is imparted to the filler at the final stage.

At this stage, the “dent” should besurrounded by a ring of bare metal, which inturn should be encircled by the finely“feathered” edge of the good paintwork.Rinse the repair area with clean water, until allof the dust produced by the rubbing-downoperation has gone.

Spray the whole area with a light coat ofprimer - this will show up any imperfections inthe surface of the filler. Repair theseimperfections with fresh filler paste orbodystopper, and once more smooth thesurface with abrasive paper. Repeat thisspray-and-repair procedure until you aresatisfied that the surface of the filler, and thefeathered edge of the paintwork, are perfect.Clean the repair area with clean water, andallow to dry fully.

The repair area is now ready for finalspraying. Paint spraying must be carried outin a warm, dry, windless and dust-freeatmosphere. This condition can be createdartificially if you have access to a large indoorworking area, but if you are forced to work inthe open, you will have to pick your day verycarefully. If you are working indoors, dousingthe floor in the work area with water will helpto settle the dust which would otherwise be inthe atmosphere. If the repair area is confinedto one body panel, mask off the surroundingpanels; this will help to minimise the effects ofa slight mis-match in paint colours. Bodyworkfittings (eg chrome strips, door handles etc)will also need to be masked off. Use genuinemasking tape, and several thicknesses ofnewspaper, for the masking operations.

Before commencing to spray, agitate theaerosol can thoroughly, then spray a test area(an old tin, or similar) until the technique ismastered. Cover the repair area with a thickcoat of primer; the thickness should be builtup using several thin layers of paint, ratherthan one thick one. Using 400-grade wet-and-dry paper, rub down the surface of the primeruntil it is really smooth. While doing this, thework area should be thoroughly doused withwater, and the wet-and-dry paper periodicallyrinsed in water. Allow to dry before sprayingon more paint.

Spray on the top coat, again building up thethickness by using several thin layers of paint.Start spraying at one edge of the repair area,and then, using a side-to-side motion, workuntil the whole repair area and about 2 inchesof the surrounding original paintwork iscovered. Remove all masking material 10 to15 minutes after spraying on the final coat ofpaint.

Allow the new paint at least two weeks toharden, then, using a paintwork renovator, ora very fine cutting paste, blend the edges ofthe paint into the existing paintwork. Finally,apply wax polish.

Plastic componentsWith the use of more and more plastic body

components by the vehicle manufacturers (egbumpers. spoilers, and in some cases majorbody panels), rectification of more seriousdamage to such items has become a matterof either entrusting repair work to a specialistin this field, or renewing completecomponents. Repair of such damage by theDIY owner is not really feasible, owing to thecost of the equipment and materials requiredfor effecting such repairs. The basic techniqueinvolves making a groove along the line of thecrack in the plastic, using a rotary burr in apower drill. The damaged part is then welded

back together, using a hot-air gun to heat upand fuse a plastic filler rod into the groove.Any excess plastic is then removed, and thearea rubbed down to a smooth finish. It isimportant that a filler rod of the correct plasticis used, as body components can be made ofa variety of different types (eg polycarbonate,ABS, polypropylene).

Damage of a less serious nature (abrasions,minor cracks etc) can be repaired by the DIYowner using a two-part epoxy filler repairmaterial. Once mixed in equal proportions,this is used in similar fashion to the bodyworkfiller used on metal panels. The filler is usuallycured in twenty to thirty minutes, ready forsanding and painting.

If the owner is renewing a completecomponent himself, or if he has repaired itwith epoxy filler, he will be left with theproblem of finding a suitable paint for finishingwhich is compatible with the type of plasticused. At one time, the use of a universal paintwas not possible, owing to the complex rangeof plastics encountered in body componentapplications. Standard paints, generallyspeaking, will not bond to plastic or rubbersatisfactorily. However, it is now possible toobtain a plastic body parts finishing kit whichconsists of a pre-primer treatment, a primerand coloured top coat. Full instructions arenormally supplied with a kit, but basically, themethod of use is to first apply the pre-primerto the component concerned, and allow it todry for up to 30 minutes. Then the primer isapplied, and left to dry for about an hourbefore finally applying the special-colouredtop coat. The result is a correctly-colouredcomponent, where the paint will flex with theplastic or rubber, a property that standardpaint does not normally possess.

6 Bodywork repair - major damage 5

1 Major damage must be repaired by aqualified bodywork repair specialist, orpreferably by a BMW dealer. Specialisedequipment is required to do the job properly.2 If the damage is extensive, the bodyshellmust be checked for proper alignment, or thevehicle’s handling characteristics may beadversely affected and other componentsmay wear at an accelerated rate.3 Due to the fact that all of the major bodycomponents (bonnet, wings, etc.) areseparate units, any seriously damagedcomponents should be replaced with newones rather than repaired.

Bodywork and fittings 11•3

11

If bodystopper is used, it canbe mixed with cellulosethinners to form a really thinpaste which is ideal for fillingsmall holes

Sometimes bodyworkcomponents can be found ina scrapyard that specialisesin used vehicle components,

often at a considerable saving over thecost of new parts.

7 Hinges and locks -maintenance 1

Every six months or so, the hinges and lockassemblies on the doors, bonnet and the bootlid/tailgate should be given a few drops oflight oil or lock lubricant. The door or tailgatelock strikers should also be lubricated with athin coat of grease, to reduce wear andensure free movement.

8 Fixed glass - renewal 5Renewal of the windscreen and fixed glass

requires the use of special fast-settingadhesive materials, and some specialisedtools and techniques. These operationsshould be left to a dealer service departmentor windscreen specialist.

9 Radiator grille -removal and refitting 1

3-Series1 Detach the clips along the top of the grille(see illustration).

2 Remove the screws, and lift the centre andside grilles out (see illustrations).3 Refitting is the reverse of removal.

5-Series

E28 (“old-shape”) models6 Remove the screws, and detach the centreand side grille pieces.7 Refitting is the reverse of removal.

E34 (“new-shape”) modelsCentre grille8 Remove the screws and detach theheadlight covers in the engine compartmentfor access.9 Remove the screw, and lift out the plasticcover behind the centre grille for access to theclips.10 From the engine compartment, reachunder the headlight housings and detach theclips retaining the centre grille valances, thenpush the grille forwards (see illustration).11 Use a screwdriver to depress the clips,detach the grille assembly and remove it bypulling it straight out.12 Refit the centre grille by placing it inposition and pushing it straight back until itclips into place.Side grille13 Remove the centre grille.14 Remove the screws, and lift the side grilleassembly out (see illustration).15 Refitting is the reverse of removal.

10 Bonnet - removal, refitting andadjustment 1

Note: The bonnet is heavy and somewhatawkward to remove and refit - at least twopeople should perform this procedure.


3-Series models1 Open the bonnet. Scribe or draw alignmentmarks around the bolt heads to ensure properalignment on refitting (see illustration).2 Disconnect the earth cable and windscreenwasher hose from the bonnet.3 Detach the bonnet hinge rod clip and


10.3a Use needle-nose pliers to pull offthe hinge pin clip . . .

10.1 Use paint or a marking pen to markon the hinge plate around the bolt heads -

mark around the entire hinge plate, ifdesired, before adjusting the bonnet

9.14 Remove the screws and pull the sidegrille assembly straight out

9.10 Detach the centre grille valance byreaching under each headlight and

pressing on the release lever

9.2b Side grille screw locations (arrowed)9.2a The centre grille is held in place bytwo screws (arrowed)

9.1 Open the bonnet and remove the grilleretaining clips (arrowed)

remove the pin (see illustrations). Be sure tosupport the bonnet while doing this.4 Have an assistant hold onto the bonnet onone side while you hold the other side.5 Remove the bonnet-to-hinge assemblybolts on your side of the bonnet, then holdyour side of the bonnet while your assistantremoves the bonnet-to-hinge bolts on theother side.6 Remove the bonnet. Place it somewheresafe where it will not be knocked over, withrags to protect the paintwork where it rests onthe ground or against a wall.7 Refitting is the reverse of removal.

5-Series models8 Open the bonnet. On some later models, itmay be necessary to prise out the plastic clipsand remove the insulation pad for access to

the bonnet light connector and windscreenwasher hoses (see illustrations). Havingdone this, disconnect the wires and hoses.9 Detach the clips and withdraw the bonnetsupport pins (see illustration).10 Remove the pins from the hinges (seeillustration).11 Have an assistant hold onto the bonnet onone side while you hold the other side.12 Remove the bonnet-to-hinge through-bolton your side of the bonnet, then hold yourside of the bonnet while your assistantremoves the through-bolt on the other side(see illustration).13 Remove the bonnet. Place it somewheresafe where it will not be knocked over, withrags to protect the paintwork where it rests onthe ground or against a wall.14 Refitting is the reverse of the removal.

Adjustment15 The bonnet can be adjusted to obtain aflush fit between the bonnet and wings afterloosening the bonnet hinge bolts. On some 5-Series models, it will be necessary to remove theside grille sections for access to the hinge bolts.16 Move the bonnet from side to side, orfront to rear, until the bonnet is properlyaligned with the wings at the front. Tighten thebolts securely.17 The rear height of the bonnet can beadjusted by loosening the bolts, and raising orlowering the catch (see illustration). Afteradjustment, tighten the bolts securely.18 Side-to-side adjustment of the bonnet canbe made by loosening the roller guide boltnuts, and moving the guide position until itslides into the catch properly (see illustration).


10.8b . . . prise the retainer out10.8a Use a small screwdriver to prise outthe clip pin, then . . .

10.3b . . . and pull the hinge pin out whilesupporting the bonnet

10.19 Screw the bonnet stops in or outafter making other adjustments

10.18 Loosen the bolts (A) and adjust theroller guide from side to side until it

engages securely in the catch

10.17 Loosen the bolts (arrowed) and raiseor lower the catch to adjust the bonnet

height

10.12 Unscrew the hinge through-bolts(arrowed)

10.10 Support the bonnet and withdrawthe pin

10.9 Pull off the clip with needle-nosepliers

11

19 After adjustment, screw the stop pads inor out to support the bonnet in its newposition (see illustration).20 The bonnet mechanism should belubricated periodically with grease, to preventsticking or jamming.

11 Bumpers - removal and refitting 1

Removal1 Detach the bumper cover (if applicable) andwhere necessary the front spoiler.2 Disconnect any wiring or other componentsthat would interfere with bumper removal.3 Support the bumper with a jack or axlestand. Alternatively, have an assistant supportthe bumper as the bolts are removed.4 Remove the retaining bolts and detach thebumper.

Refitting5 Refitting is a reversal of removal. Tightenthe retaining bolts securely, then refit thebumper cover and any other components thatwere removed.

12 Door trim panel - removal and refitting 1

Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation code before

disconnecting the battery, Refer to theinformation on page 0-7 at the front of thismanual before detaching the cable.


Removal1 Disconnect the battery negative cable.2 Remove all door trim panel retaining screwsand door pull/armrest assemblies.

3 On models with manual (non-electric)windows, remove the window regulatorhandle (see illustration). On models withelectric windows, prise off the control switchassembly and unplug it.4 Disengage the trim panel-to-door retainingclips. Work around the outer edge until thepanel is free.5 Once all of the clips are disengaged, detachthe trim panel, unplug any electricalconnectors, and remove the trim panel fromthe vehicle.6 For access to the inner door, carefully peelback the plastic water shield.

Refitting7 Prior to refitting the door trim panel, be sureto renew any clips in the panel which mayhave come out (or got broken) during theremoval procedure.8 Plug in the electrical connectors (whereapplicable) and place the panel in position inthe door. Press the door panel into place untilthe clips are seated, then refit thearmrest/door pulls. Refit the window regulatorhandle, where applicable.

13 Door - removal, refitting andadjustment 1

Removal1 Remove the door trim panel (see Section12). Disconnect any electrical connectors, and

push them through the door opening so theywon’t interfere with door removal.2 Place a trolley jack or axle stand under thedoor, or have an assistant on hand to supportit when the hinge bolts are removed. Note: If ajack or axle stand is used, place a rag betweenit and the door, to protect the door’s paintedsurfaces.3 Scribe or mark around the door hinges.4 Disconnect the door check strap by prisingthe circlip out of the end of the pin, then slidethe pin out (see illustration). A roll pin is fittedto some models; this is removed by driving itout with a pin punch.5 Remove the hinge-to-door nuts, andcarefully lift off the door (see illustration).

Refitting and adjustment6 Refitting is the reverse of removal.7 Following refitting of the door, check thealignment and adjust it if necessary asfollows:a) Up-and-down and fore-and-aft

adjustments are made by loosening thehinge-to-body nuts and moving the dooras necessary.

b) The door lock striker can also be adjustedboth up and down and sideways, toprovide positive engagement with the lockmechanism. This is done by loosening themounting bolts and moving the striker asnecessary (see illustration).

14 Boot lid/tailgate - removal,refitting and adjustment 1

Boot lid1 Open the boot lid, and cover the edges ofthe boot compartment with pads or cloths toprotect the painted surfaces when the lid isremoved.2 Disconnect any cables or electricalconnectors attached to the boot lid that wouldinterfere with removal.3 Make alignment marks around the hingebolts (see illustration).4 Have an assistant support the lid, thenremove the lid-to-hinge bolts on both sidesand lift it off.


13.7 The door lock striker position can beadjusted after loosening the screws

(arrowed)13.5 Remove the nuts (arrowed) and

detach the door from the hinges

13.4 Detach the circlip (arrowed) from thetapered end of the pin

12.3 On models without electric windows,prise off the window regulator handle trim

piece for access to the retaining screw

5 Refitting is the reverse of removal. Align thelid-to-hinge bolts with the marks made duringremoval.6 After refitting, close the lid and make sureit’s in proper alignment with the surroundingpanels. Fore-and-aft and side-to-sideadjustments are controlled by the position ofthe hinge bolts in the slots. To make anadjustment, loosen the hinge bolts, repositionthe lid, and retighten the bolts.7 The height of the lid in relation to thesurrounding body panels when closed can bechanged by loosening the lock and/or strikerbolts, repositioning the striker and/or lock,and tightening the bolts (see illustrations).


before disconnecting the battery, Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.

Tailgate8 Disconnect the battery negative cable.9 Open the tailgate and cover the rear edgeof the roof with pads or cloths to protect thepainted surfaces when the tailgate is

removed. On 5-Series models, the windowmay be removed separately by disconnectingthe wiring and unscrewing the mountingscrews - have an assistant hold the windowwhile the screws are being loosened (seeillustration).10 Remove the trim from the inside of thetailgate. Also where necessary on 5-Seriesmodels, remove the edge covers for access tothe strut mountings.11 Disconnect the wiring loom and thewasher tubing. On some models, it will benecessary to pull the wiring loom out of therear pillar and then disconnect the plug (seeillustration).12 While an assistant holds the tailgate open,

disconnect the struts on both sides byunscrewing the mounting screws. Whereapplicable, pull out the retaining pin or springclip, and remove the strut from the ball (seeillustrations).13 Mark the position of the hinge arms on thetailgate with a pencil.14 Unscrew the bolts and withdraw thetailgate from the hinge arms. On 5-Seriesmodels, it will be necessary to use an Allenkey or bit (see illustration).15 Refitting is the reverse of removal, butmake sure that the previously-made marksare correctly aligned. Check that the tailgatecloses centrally between the rear pillars andenters the lock correctly.


14.7b Adjust the boot lid lock striker afterloosening the bolts (arrowed)

14.7a Loosen the lock bolts (arrowed) andmove the lock to adjust the boot lid closing

position

14.3 Mark around the hinge bolts so youcan refit the boot lid in its original location- unscrew or loosen the boot lid-to-hinge

bolts to remove or adjust it

14.12c Removing the retaining pin todisconnect the bottom of the tailgate

support strut (5-Series)

14.12b Strut mounting on the tailgate (5-Series)

14.12a Removing the tailgate strut springclip (3-Series)

14.11 Removing the wiring from the rearpillar (5-Series)

14.9 Tailgate window mounting screws (5-Series)

11

15 Latch, lock cylinder andhandles - removal, refittingand adjustment

11 Remove the trim panel(s) and, on the door,the plastic shield (see Section 12).

Latch2 Disconnect the operating rods from thelatch (see illustration).3 Remove the latch retaining screws.4 Detach the latch assembly and withdraw it.5 Refitting is the reverse of removal.

Lock cylinder6 Detach the linkage.7 Use a screwdriver to slide the retaining clipoff, and withdraw the lock cylinder.8 Refitting is the reverse of removal.

Interior handle9 Disconnect the operating rod from thehandle.10 Remove the retaining screws and lift thehandle from the door.11 Refitting is the reverse of removal.

Exterior handle12 Lift up the handle for access, remove thetwo retaining screws, then detach the handlefrom the door.13 Refitting is the reverse of removal.

16 Door window glass - removal and refitting 3



1 Disconnect the battery negative cable.2 Remove the door trim panel and the plasticwater shield (see Section 12).3 Prise the door inner and outer weatherstripsfrom the door.

Front door4 Raise the window so that the mountingbolts can be reached through the access hole.If electric windows are fitted, temporarilyreconnect the battery cable to accomplishthis.5 Support the glass, and remove the retainingbolts securing the glass to the regulator.6 Lift the window glass up and out of the doorwindow slot, then tilt it and remove it from thedoor.7 Refitting is the reverse of removal.

Rear door8 Carry out the operations described inparagraphs 1 to 5.

3-Series models9 Disengage the glass from the front guideroller, and prise out the rubber windowguides.10 Remove the door handle screws, andallow the handle assembly to hang out of theway.11 Remove the rear window frame bolts,push the frame into the door, and remove thewindow glass.12 Refitting is the reverse of removal.

5-Series models13 Loosen the rear window guide mountingbolt.

14 Detach the glass from the front guideroller, disengage the glass from the guiderails, then slide the glass to the rear andremove by lifting from above.15 The fixed glass can be removed byremoving the guide rail bolts, then pulling therail down to the rear and detaching the glass.16 Refitting is the reverse of removal. Therear window glass can be adjusted byloosening the adjustment bolts, then raisingthe glass to within one inch of the top of thedoor opening. Adjust the glass-to-opening gap evenly, then tighten the boltssecurely.

17 Door window regulator -removal and refitting 3

Removal1 Remove the door window glass (Sec-tion 16).2 Remove the securing bolts or nuts, and liftthe window regulator assembly out of thedoor (withdraw the regulator mechanismthrough the access hole). On models withelectric windows, unplug the electricalconnector.


18 Exterior mirror - removal and refitting 1

Removal1 If it is required to renew the mirror glassonly, insert a small screwdriver through thehole in the bottom of the exterior mirror, andcarefully lever clockwise the plastic holder onthe rear of the glass (ie move the bottom ofthe screwdriver to the right). This will releasethe glass, which can then be withdrawn. Ifelectric mirrors are fitted, it will be necessaryto disconnect the wiring before completelyremoving the glass.2 To remove the complete mirror, prise offthe cover panel (and/or the tweeter speaker,where applicable).3 Unplug the electrical connector.4 Remove the retaining screws and lift themirror off



15.2 Typical door latch, lock cylinder andhandle details

14.14 Unscrewing the hinge mountingbolts (5-Series)

19 Steering column shrouds -removal and refitting 1



Removal1 Disconnect the battery negative cable.2 Remove the steering wheel (Chapter 10).3 Remove the upper shroud screws (seeillustration).4 Remove the two screws from the undersideof the column (see illustration).5 Detach the lower shroud, then lift the upperhalf off the column (see illustrations).


20 Seats - removal and refitting 1Front seat1 Remove the four bolts securing the seattrack to the floorpan, and lift the seat from thevehicle (see illustration). On some models, itwill be necessary to disconnect the seatheating wiring; it may also be necessary todetach the seat belt from the seat.

2 Refitting is the reverse of removal. Tightenthe retaining bolts securely.

Rear seat cushion3 If applicable, first remove the two retainingbolts. Grasp the front of the cushion(Saloon/Convertible models) or the rear of thecushion (Touring/Estate models) securely, andpull up sharply (see illustration).4 Refitting is the reverse of the removal.

21 Seat belt check 11 Check the seat belts, buckles, lock platesand guide loops for obvious damage andsigns of wear.2 Where applicable, check that the seat beltreminder light comes on when the ignition keyis turned to the Run or Start position.3 The seat belts are designed to lock upduring a sudden stop or impact, yet allow freemovement during normal driving. Check that

the retractors return the belt against yourchest while driving and rewind the belt fullywhen the buckle is unlocked.4 If any of the above checks reveal problemswith the seat belt system, renew parts asnecessary.5 Belts which have been subject to impactloads must be renewed.


19.5a Pull the tilt lever down (where fitted),and lower the shroud from the steering

column

19.4 The lower screws are located underthe tilt lever (where fitted)

19.3 Use a Phillips screwdriver to removethe upper column shroud screws

20.3 Grasp the seat at the front edge andpull up sharply (Saloon/Convertible

models)

20.1 The front seats are held in place bybolts (arrowed)

19.5b Rotate the upper shroud up and offthe steering column

11

12

Chapter 12 Body electrical systems

Bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Central locking system - description and check . . . . . . . . . . . . . . . . 20Cruise control system - description and check . . . . . . . . . . . . . . . . 19Direction indicator/hazard warning flasher - check and renewal . . . 5Electric windows - description and check . . . . . . . . . . . . . . . . . . . . 21Electrical system fault finding - general information . . . . . . . . . . . . . 2Fuses - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Headlight housing - removal and refitting . . . . . . . . . . . . . . . . . . . . . 14Headlights - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Headlights - bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Heated rear window - check and repair . . . . . . . . . . . . . . . . . . . . . . 17Ignition switch - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 7Instrument cluster - removal and refitting . . . . . . . . . . . . . . . . . . . . . 10Radio - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Radio aerial - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 9Relays - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Service Indicator (SI) board - general information . . . . . . . . . . . . . . 11Steering column switches - removal and refitting . . . . . . . . . . . . . . . 6Supplemental Restraint System (SRS) - general information . . . . . . 18Windscreen/tailgate wiper motor - removal and refitting . . . . . . . . . 16Wiring diagrams - general information . . . . . . . . . . . . . . . . . . . . . . . 22

12•1







Contents


The chassis electrical system of this vehicleis of 12-volt, negative earth type. Power forthe lights and all electrical accessories issupplied by a lead/acid-type battery, which ischarged by the alternator.

This Chapter covers repair and serviceprocedures for various chassis (non-enginerelated) electrical components. Forinformation regarding the engine electricalsystem components (battery, alternator,distributor and starter motor), see Chapter 5.

Warning: To prevent electricalshort-circuits, fires and injury,always disconnect the batterynegative terminal before

checking, repairing or renewing electricalcomponents.



2 Electrical system faultfinding - general information 2

A typical electrical circuit consists of anelectrical component, any switches, relays,motors, fuses, fusible links or circuit breakers,etc related to that component, and the wiringand connectors that link the components toboth the battery and the chassis. To help youpinpoint an electrical circuit problem, wiringdiagrams are included at the end of this book.

Before tackling any troublesome electricalcircuit, first study the appropriate wiringdiagrams to get a complete understanding ofwhat makes up that individual circuit.Troublespots, for instance, can often beisolated by noting if other components relatedto that circuit are routed through the samefuse and earth connections.

Electrical problems usually stem fromsimple causes such as loose or corrodedconnectors, a blown fuse, a melted fusiblelink, or a bad relay. Inspect all fuses, wiresand connectors in a problem circuit first.

The basic tools needed include a circuittester, a high-impedance digital voltmeter, acontinuity tester and a jumper wire with an in-line circuit breaker for bypassing electricalcomponents. Before attempting to locate ordefine a problem with electrical test

instruments, use the wiring diagrams todecide where to make the necessaryconnections.

Voltage checksPerform a voltage check first when a circuit

is not functioning properly. Connect one leadof a circuit tester to either the negative batteryterminal or a known good earth.

Connect the other lead to a connector inthe circuit being tested, preferably nearest tothe battery or fuse. If the bulb of the testerlights up, voltage is present, which means thatthe part of the circuit between the connectorand the battery is problem-free. Continuechecking the rest of the circuit in the samefashion.

When you reach a point at which no voltageis present, the problem lies between that pointand the last test point with voltage. Most ofthe time, problems can be traced to a looseconnection. Note: Keep in mind that somecircuits receive voltage only when the ignitionkey is turned to a certain position.

Electrical fault diagnosis is simple if youkeep in mind that all electrical circuits arebasically electricity running from the battery,through the wires, switches, relays, fuses andfusible links to each electrical component(light bulb, motor, etc) and then to earth, fromwhere it is passed back to the battery. Anyelectrical problem is an interruption in the flowof electricity to and from the battery.

Finding a short-circuitOne method of finding a short-circuit is to

remove the fuse and connect a test light orvoltmeter in its place. There should be novoltage present in the circuit. Move theelectrical connectors from side-to-side whilewatching the test light. If the bulb goes on,there is a short to earth somewhere in thatarea, probably where the insulation has beenrubbed through. The same test can beperformed on each component in a circuit,even a switch.

Earth checkPerform a earth check to see whether a

component is properly earthed (passingcurrent back via the vehicle body). Disconnectthe battery, and connect one lead of a self-powered test light (often known as acontinuity tester) to a known good earth.Connect the other lead to the wire or earthconnection being tested. The bulb shouldlight, indicating a good earth connection. Ifnot, dismantle the connection, and clean allrelevant parts thoroughly. When re-makingthe connection, use serrated (shakeproof)washers if possible, and tighten all bolts, etc,securely.



Continuity checkA continuity check determines if there are

any breaks in a circuit - if it is conductingelectricity properly. With the circuit off (nopower in the circuit), a self-powered continuitytester can be used to check the circuit.Connect the test leads to both ends of thecircuit, and if the test light comes on, thecircuit is passing current properly. If the lightdoesn’t come on, there is a break somewherein the circuit. The same procedure can beused to test a switch, by connecting thecontinuity tester to the power-in and power-out sides of the switch. With the switch turnedon, the test light should come on.

Finding an open-circuitWhen diagnosing for possible open-

circuits, it is often difficult to locate them bysight, because oxidation or terminalmisalignment are hidden by the connectors.Intermittent problems are often caused byoxidised or loose connections. Merelywiggling an electrical connector may correctthe open-circuit condition, albeit temporarily.Dismantle the connector, and spray with awater-dispersant aerosol. On simplerconnectors, it may be possible to carefully

bend the connector pins inside, to improvethe metal-to-metal contact - don’t damagethe connector in the process, however.

3 Fuses - general information 1The electrical circuits of the vehicle are

protected by a combination of fuses andcircuit breakers. The fusebox is located in theleft corner of the engine compartment (seeillustration). On some later models, it islocated under the rear seat cushion.

Each of the fuses is designed to protect aspecific circuit, and on some models, thevarious circuits are identified on the fusepanel itself.

Miniaturised fuses are employed in thefuseboxes. These compact fuses, with bladeterminal design, allow fingertip removal andrenewal. If an electrical component fails,always check the fuse first. A blown fuse iseasily identified through the clear plasticbody. Visually inspect the element forevidence of damage. If a continuity check iscalled for, the blade terminal tips are exposedin the fuse body.

Be sure to renew blown fuses with thecorrect type. Fuses of different ratings arephysically interchangeable, but only fuses ofthe proper rating should be used. Replacing afuse with one of a higher or lower value thanspecified is not recommended. Each electricalcircuit needs a specific amount of protection.The amperage value of each fuse is mouldedinto the fuse body.

If the new fuse immediately fails, don’trenew it again until the cause of the problemis isolated and corrected. In most cases, thecause will be a short-circuit in the wiringcaused by a broken or deteriorated wire.

4 Relays - general information 1Several electrical accessories in the vehicle

use relays to transmit the electrical signal tothe component. If the relay is defective, that

component will not operate properly. Relaysare electrically-operated switches, which areoften used in circuits drawing high levels ofcurrent, or where more complex switchingarrangements are required.

The various relays are grouped together forconvenience in several locations under thedash and in the engine compartment (seeaccompanying illustration and illus-tration 3.1).

If a faulty relay is suspected, it can beremoved and tested by a dealer or qualifiedautomotive electrician. No overhaul ispossible. Like fuses, defective relays must bereplaced with the correct type; some relayslook identical, but perform very differentfunctions.

5 Direction indicator/hazardwarning flasher unit - checkand renewal

2Warning: Some later models areequipped with an airbag orSupplemental Restraint System(SRS). To avoid possible damage

to this system, the manufacturerrecommends that, on airbag-equippedmodels, the following procedure should beleft to a dealer service department, orother specialist, because of the specialtools and techniques required. There is arisk of injury if the airbag is accidentallytriggered.1 The direction indicator/hazard flasher unit isa small canister- or box-shaped unit locatedin the wiring harness on or near the steeringcolumn. Access is gained by removing thesteering column shrouds (see illustration).2 When the flasher unit is functioningproperly, a regular clicking noise can be heardfrom it when the indicators or hazard flashersare switched on. If the direction indicators failon one side or the other, and the flasher unitdoes not make its characteristic clickingsound, a faulty direction indicator bulb isindicated.3 If both direction indicators fail to blink, theproblem may be due to a blown fuse, a faultyflasher unit, a broken switch or a loose or openconnection. If a quick check of the fusebox

12•2 Body electrical systems

4.2 Engine compartment relays3.1 The fusebox is located in the engine

compartment under a cover - the box alsoincludes several relays

indicates that the direction indicator and/orhazard fuse has blown, check the wiring for ashort-circuit before fitting a new fuse.4 Make sure that the new unit is identical tothe original. Compare the old one to the newone before fitting it.5 Refitting is the reverse of removal.

6 Steering column switches -removal and refitting 1

Warning: Some later models areequipped with an airbag orSupplemental Restraint System(SRS). To avoid possible damage

to this system, the manufacturerrecommends that, on airbag-equippedmodels, the following procedure should beleft to a dealer service department, orother specialist, because of the specialtools and techniques required. There is arisk of injury if the airbag is accidentallytriggered.


before disconnecting the battery, Refer tothe information on page 0-7 at the front ofthis manual before detaching the cable. Note: If, after connecting the battery, thewrong language appears on the instrumentpanel display, refer to page 0-7 for thelanguage resetting procedure.1 Disconnect the battery negative cable,remove the steering wheel (see Chapter 10)and steering column shrouds (see Chapter 11).

Direction indicator/headlightswitch2 Where necessary, remove the switchmounting screws. Depress the tabs and pullthe switch out of the steering columnmounting (see illustration).3 Trace the switch wires down the steeringcolumn to the electrical connector, andunplug them (see illustration).4 Refitting is the reverse of removal.

Wiper/washer switch5 Where necessary, remove the switchmounting screws.6 Depress the release clip, and detach theswitch from the steering column mounting(see illustration). Trace the switch wiringdown the steering column to the electricalconnector, and unplug it.7 Refitting is the reverse of removal.

Cruise control switch8 Remove the wiper/washer switch.9 Where necessary, remove the switchmounting screw. Squeeze the release tabs,and withdraw the switch from the mounting(see illustration).10 Disconnect the switch electricalconnector from the harness at the base of thesteering column.11 Refitting is the reverse of removal.

7 Ignition switch - removal and refitting 1

Warning: Some later models areequipped with an airbag orSupplemental Restraint System(SRS). To avoid possible damage

to this system, the manufacturerrecommends that, on airbag-equippedmodels, the following procedure should beleft to a dealer service department, orother specialist, because of the special

tools and techniques required. There is arisk of injury if the airbag is accidentallytriggered.



Removal1 Disconnect the battery negative cable.2 Remove the steering wheel (see Chap-ter 10).3 Remove the steering column shrouds (seeChapter 11).4 Where necessary, remove the directionindicator/headlight control switch (see Sec-tion 6).5 Detach the clips by inserting a smallscrewdriver into the openings on the sideswhile pulling out on the switch (seeillustration).6 Unplug the electrical connector from theharness at the base of the steering column,and remove the switch.


Body electrical systems 12•3

6.3 Follow the wiring down the steeringcolumn to the connector

6.2 Squeeze the tabs to release the switchfrom the mounting

6.9 Cruise control switch removal6.6 Squeeze the wiper/washer switch tabsand pull it directly out of the mounting

12

5.1 The direction indicator/hazard warningflasher unit is located on the steeringcolumn on most models - squeeze the

tabs to detach it

8 Radio - removal and refitting 1Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation code


Removal1 Disconnect the battery negative cable.2 The radios on most models are held in placeby internal clips which are usually located atthe sides or corners of the unit faceplate.Removal requires a special tool which isinserted into the holes to release the clips sothe radio can be pulled out. These tools can befabricated from heavy wire, or are availablefrom your dealer or a car audio specialist. Onanti-theft radios, the clips are moved in andout by internal screws which require anothertype of tool. Insert the tool into the holes untilthe clips release, then withdraw the radio fromthe dash panel. Disconnect the wiring from theradio and remove it.

3 On some models, the radio is held in placeby screws located beneath the faceplate. Thecontrol knobs must be pulled off before thefaceplate can be withdrawn.


9 Aerial - removal and refitting 1Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation code


Removal1 Disconnect the battery negative cable.2 Use circlip pliers to unscrew the aerialmounting nut.3 Open the boot lid/tailgate and remove theleft side trim panel. On some models, the jackand tail light cluster cover will have to beremoved first.4 Unplug the aerial power and radio leadconnectors (as applicable), remove theretaining bolts, and remove the aerial andmotor assembly.


10 Instrument cluster - removal and refitting 2

Caution: The instrument clusterand components are verysusceptible to damage fromstatic electricity. Make sure youare earthed and have discharged

any static electricity (by touching an objectsuch as a metal water pipe) beforetouching the cluster or components.



Removal1 Disconnect the battery negative cable.2 As necessary, remove the steering columnshrouds and lower trim panel (see Chap-ter 11).3 Remove the screws holding the cluster tothe facia (see illustration). Note the locationof the lower screws to ensure they are refittedin the same place. On 3-Series models, thelength of the two lower inner screws must notexceed 9.5 mm.4 Tilt the top of the cluster back, reachbehind it and detach the electrical connectorsby pressing on the levers, then lift the clusterout of the facia opening (see illustration).5 For access to the cluster components,release the catches or remove the screws,and separate the two halves (seeillustration).


11 Service Indicator (SI) board -general information

All models that have service indicator lightsare equipped with a Service Indicator (SI)board located in the instrument cluster. Thisboard turns the lights on at the proper mileageintervals. The lights can only be turned offusing a special tool which plugs into theengine check connector (see Chapter 1). The


10.5 Turn the plastic knobs to release theback of the cluster (some models use

screws)

10.4 Push on the levers to detach thecluster electrical connectors

10.3 Use a Phillips screwdriver to removethe instrument cluster retaining screws

7.5 Insert a screwdriver into the openings(arrowed) on each side of the switch to

release the clip while pulling out

SI board is a self-contained computer whichincludes a chip and batteries.

The rechargeable SI board nickel cadmium(nicad) batteries maintain power to thecomputer memory in the event of a powerdrop (such as during starting) or completepower loss (such as a dead or disconnectedbattery) (see illustration). This assures powerso the computer can continue to keep track ofmileage and turn the lights on at the properinterval.

The batteries have a life of approximatelysix years, at which time they must be replacedwith new ones. Also, since they are rechargedby the engine charging system, they can rundown prematurely if power is cut off for somereason (such as a blown fuse, a fault in thewiring, or extended storage of the vehicle).Excessive heat or cold can also shortenbattery life, with heat the greatest enemy.Extreme heat can cause the batteries toactually split open, allowing acid to drip intothe instrument cluster.

Several instruments controlled by the SIboard can be affected by low or dischargedbatteries. Symptoms of low or dead SI boardbatteries can include inconsistent tachometerand temperature gauge readings, backgroundradio noise, and the inability to turn theservice lights off with the special tool.

Although only complete SI boards areavailable from the manufacturer, batteries areavailable separately from aftermarket sources.While it is possible for the home mechanic torenew the batteries, they are soldered to theboard, so unless you are skilled at this andhave the proper tools, this job should be leftto an experienced electronics technician.Considerable savings can be realised byremoving the instrument cluster (see Section 10) and taking it to an electronicsspecialist.

Caution: the instrument clusterand components are verysusceptible to damage fromstatic electricity. Make sure you

are earthed and have discharged anystatic electricity (by touching an objectsuch as a metal water pipe) beforetouching the cluster components.

12 Headlights - bulb renewal 1Caution: If the radio in yourvehicle is equipped with an anti-theft system, make sure you havethe correct activation code



Sealed-beam type2 Remove the grille (see Chapter 11).3 Remove the headlight retainer screws,taking care not to disturb the adjustmentscrews.4 Remove the retainer and pull the headlightout enough to allow the connector to beunplugged.5 Remove the headlight.6 To refit the headlight, plug the connector in,place the headlight in position, and refit theretainer and screws. Tighten the screwssecurely.

7 Refit the grille. Connect the battery negativecable.

Halogen bulb typeWarning: Halogen gas-filled bulbsare under pressure, and mayshatter if the surface is scratched

or the bulb is dropped. Wear eyeprotection, and handle the bulbs carefully,grasping only the base whenever possible.Do not touch the surface of the bulb withyour fingers, because the oil from yourskin could cause it to overheat and failprematurely.

8 From behind the headlight assembly,remove the outer cover (see illustration).9 Twist and release the inner cover from therear of the headlight (see illustration).10 Disconnect the wire from the rear of theheadlight bulb (see illustration).11 Release the clips, and withdraw the bulbfrom the headlight unit (see illustration).12 Fit the new bulb using a reversal of theremoval procedure. Make sure that the clipsengage the bulb correctly.13 Connect the battery negative cable.


12.9 Twist and release the headlight innercover

12.8 Removing the headlight rear outercover (3-Series shown)

11.2 These batteries (arrowed) power theService Indicator (SI) board

12.11 Removing the headlight bulb (do nottouch the surface of the bulb with your

fingers)

12.10 Disconnecting the wire from the rearof the headlight bulb

12

If you do touch the headlampbulb surface, clean it withmethylated spirit.

13 Headlights - adjustment 2Note: The headlights must be aimed correctly.If adjusted incorrectly, they could momentarilyblind the driver of an oncoming vehicle andcause a serious accident, or seriously reduceyour ability to see the road. The headlightsshould be checked for proper aim every 12 months (as is done during the MOT test),and any time a new headlight is fitted or front-end body work is performed. It should beemphasised that the following procedure willonly provide a temporary setting until theheadlights can be adjusted by a properly-equipped garage.1 Each headlight has two adjusting screws,one controlling up-and-down movement andone controlling left-and-right movement (seeillustration). It may be necessary to removethe grille (see Chapter 11) for access to thesescrews.2 There are several methods of adjusting theheadlights. The simplest method requires ablank wall (or garage door) 25 feet in front ofthe vehicle, and a level floor.3 Position masking tape vertically on the wall,to mark the vehicle centreline and thecentreline of both headlights. Note: It may beeasier to position the tape on the wall with thevehicle parked only a few inches away, andthen move the vehicle back the requireddistance when all marks have been made.4 Make a horizontal line on the wall to markthe centreline of all headlights.5 Move the vehicle back so that it is 25 feetaway from the marked wall (keep the front endof the vehicle square to the wall). Adjustmentshould be made with the vehicle sitting level,the fuel tank half-full, and with no unusuallyheavy loads in the vehicle.6 Switch on the dipped beam. The brightspots on the wall should be two inches belowthe horizontal line, and two inches to the leftof the headlight vertical lines. Adjustment ismade by turning the adjusting screw to raiseor lower the beam. The other adjusting screw

should be used in the same manner to movethe beam left or right.7 With main beam on, the bright spots on thewall should be exactly on the vertical lines,and just below the horizontal line. Note: It maynot be possible to position the headlight aimexactly for both main and dipped beams. If acompromise must be made, keep in mind thatthe dipped beam is most used, and will havethe greatest effect on driver safety.8 Have the headlights adjusted by a dealerservice department or qualified garage at theearliest opportunity.

14 Headlight housing - removal and refitting 1



Removal1 Disconnect the battery negative cable.

2 Remove the side grille (see Chapter 11),then remove the rear cover(s) wherenecessary.3 Unplug the headlight (sealed beam-type) orremove the bulb (halogen bulb-type).4 Remove the screws and detach the housing(see illustration).


15 Bulb renewal 11 The lenses of many lights are held in placeby screws, which makes it a simple procedureto gain access to the bulbs.2 On some lights, the lenses are held in placeby clips. The lenses can be removed by usinga small screwdriver to prise them off.3 Several bulbs are mounted in self-earthingholders, and are removed by pushing in andturning them anti-clockwise (see illustration).The bulbs can then be removed (seeillustrations).4 The tail lights on 3-Series models areaccessible after removing the housing, thenremoving the bulbs (see illustrations).5 To gain access to the facia lights, theinstrument cluster will have to be removedfirst (see illustration).


15.3c . . . then pull the bulb from theholder

15.3b On models with high-mountedcentre brake lights, the self-earthing

holder is accessible from the luggage area- pull the holder out . . .

15.3a The tail light bulbs on later 5-Seriesmodels are in self-earthing holders whichcan be simply pulled out of the housing -the bulb is then removed from the holder

14.4 Remove the screws (arrowed) anddetach the headlight housing

13.1 The headlight adjustment screws(arrowed) are accessible from the back of

the headlight on 3-Series models

16 Windscreen/tailgate wipermotor - removal and refitting 2




Windscreen wiper motor

2 Remove the covers and nuts, then detachthe wiper arms (see illustrations).3 Prise out the retaining clips and detach thecowl grille for access to the wiper assembly.4 Remove the screws or nuts and detach thewiper cover located on the enginecompartment bulkhead.5 Unplug the electrical connector and detachthe wiper linkage.6 Mark the relationship of the wiper shaft to thelinkage. Detach the wiper link from the motorshaft by prising carefully with a screwdriver.7 Remove the three retaining bolts andremove the wiper motor from the vehicle.8 Refitting is the reverse of removal. Whenfitting the motor, if necessary plug in the

connector and run the motor briefly until it isin the “neutral” (wipers parked) position.

Tailgate wiper motor9 On 3-Series models, remove the cover andnut, then detach the wiper arm (seeillustration). On 5-Series models, open therear window away from the tailgate.

10 As applicable, remove the trim panel(s),then disconnect the washer tube and thewiring plug.

11 Unscrew the mounting nuts and withdrawthe wiper motor (see illustrations). On 5-Series models, the wiper blade and pivotmechanism may be removed from the rearwindow if necessary after removing the trimpanels (see illustration).


15.5 After removing the instrument cluster(see Section 10), turn the bulbholder anti-

clockwise to remove the bulb

15.4b . . . then remove the bulb from thehousing

15.4a On 3-Series models, the entire taillight housing assembly is self-earthing

through the mounting screw - loosen theplastic screw and pull the housing back . . .

16.11a Removing the tailgate wiper motor (3-Series)

16.2b After removing the nut, use a magnet to lift out the metalwasher

16.2a Use a small screwdriver to detach the wiper arm nut cover,or swivel the cover up

16.9 Removing the tailgate wiper arm nut (3-Series)

12

12 Refitting is a reversal of removal. Whenfitting the motor, if necessary plug in theconnector and run the motor briefly until it isin the “neutral” (wiper parked) position.

17 Heated rear window - check and repair 2

1 The heated rear window consists of anumber of horizontal elements on the glasssurface.2 Small breaks in the element can be repairedwithout removing the rear window.

Check3 Switch on the ignition and the heated rearwindow.4 Place the positive lead of a voltmeter to theheater element nearest to the incoming powersource.5 Wrap a piece of aluminium foil around thenegative lead of the voltmeter on the positiveside of the suspected broken element, andslide it slowly towards the negative side.Watch the voltmeter needle - when it movesfrom zero, you have located the break.

Repair6 Repair the break in the line using a repair kitrecommended specifically for this purpose,such as BMW repair kit No. 81 22 9 (orequivalent). Included in this kit is plasticconductive epoxy. The following paragraphsgive general instructions for this type of repair;follow the instructions supplied with the repairkit if they are different.7 Prior to repairing a break, switch off thecircuit and allow it to cool down for a fewminutes.8 Lightly buff the element area with fine steelwool, then clean it thoroughly.9 Use masking tape to mask off the area ofrepair, leaving a slit to which the epoxy can beapplied.10 Mix the epoxy thoroughly, according tothe instructions on the package.11 Apply the epoxy material to the slit in themasking tape, overlapping the undamagedarea about 20 mm on each end.

12 Allow the repair to cure for 24 hoursbefore removing the tape and using theheated rear window.

18 Supplemental RestraintSystem (SRS) - generalinformation

Later models are equipped with aSupplemental Restraint System (SRS),incorporating an airbag. This system isdesigned to protect the driver from seriousinjury in the event of a head-on or frontalcollision. It consists of an airbag module in thecentre of the steering wheel, two crashsensors mounted on the front inner wingpanels, and a crash safety switch locatedinside the passenger compartment.

The airbag module contains a housingincorporating the airbag and the inflator units.The inflator assembly is mounted on the backof the housing over a hole through which gasis expelled, inflating the bag almost instanta-neously when an electrical signal is sent fromthe system. This signal is carried by a wirewhich is specially wound with several turns,so the signal will be transmitted regardless ofthe steering wheel position.

The SRS system has three sensors: two atthe front, mounted on the inner wing panels(see illustration), and a safety switch locatedinside the passenger compartment. The crashsensors are basically pressure-sensitiveswitches, which complete an electrical circuitduring an impact of sufficient force. Theelectrical signal from the crash sensors is sentto a third sensor, which then completes thecircuit and inflates the airbag.

The module containing the safety switchmonitors the system operation. It checks thesystem every time the vehicle is started,causing the AIRBAG warning light to come on,then go out if the system is operatingcorrectly. If there is a fault in the system, thelight will stay on. If the AIRBAG warning lightdoes stay on, or if it comes on while driving,take the vehicle to your dealer immediately.

19 Cruise control system -description and check 1

The cruise control system maintains vehiclespeed using a vacuum-actuated servo motorlocated in the engine compartment, which isconnected to the throttle linkage by a cable.The system consists of the servo motor,clutch switch, brake switch, control switches,a relay, and associated vacuum hoses.

Because of the complexity of the cruisecontrol system, repair should be left to adealer service department. However, it ispossible for the home mechanic to makesimple checks of the wiring and vacuumconnections for minor faults which can beeasily repaired. These include:a) Inspect the cruise control actuating switches

for broken wires and loose connections.b) Check the cruise control fuse.c) The cruise control system is operated by

vacuum, so it’s critical that all vacuumswitches, hoses and connections aresecure. Check the hoses in the enginecompartment for loose connections,cracks, or obvious vacuum leaks.

20 Central locking system -description and check 2

The central door locking system operatesthe door lock actuators mounted in eachdoor. The system consists of the switches,actuators and associated wiring. Diagnosis islimited to simple checks of the wiringconnections and actuators for minor faultswhich can be easily repaired. These include:a) Check the system fuse and/or circuit

breaker (where applicable).b) Check the switch wires for damage and

loose connections. Check the switchesfor continuity.

c) Remove the door trim panel(s), and checkthe actuator wiring connections to see ifthey’re loose or damaged. Inspect theactuator rods to make sure they aren’t


18.3 The SRS system crash sensors(arrowed) are located in the engine

compartment - check the wiring regularlyfor damage

16.11b Tailgate wiper motor (5-Series) 16.11c Wiper blade and pivot mechanismon the rear window (5-Series)

BK BlackBL BlueBR Brown

GE YellowGN GreenGR Green or Grey

GY GreyOR OrangePK Pink

R RedRS PinkRT Red

SW BlackTN TanV Violet

VI VioletWWhite

WS WhiteY Yellow


12

Colour codes

bent or damaged. The actuator can bechecked by applying battery powermomentarily. A discernible click indicatesthat the solenoid is operating properly.

21 Electric window system -description and check 2

The electric window system operates theelectric motors mounted in the doors whichlower and raise the windows. The systemconsists of the control switches, the motors,window mechanisms (regulators) and

associated wiring. Removal of the motors andregulators is described in Chapter 11.

Diagnosis is usually limited to simplechecks of the wiring connections and motorsfor minor faults which can be easily repaired.These include:a) Check the electric window switches for

broken wires and loose connections.b) Check the electric window fuse/and or

circuit breaker (where applicable).c) Remove the door trim panel(s) and check

the electric window motor wires to see ifthey’re loose or damaged. Inspect thewindow mechanisms for damage whichcould cause binding.

22 Wiring diagrams - general information

Since it isn’t possible to include all wiringdiagrams for every model year covered by thismanual, the following diagrams are those thatare typical and most commonly needed.

Prior to checking any circuit, check thefuses and circuit breakers to make sure they’rein good condition. Make sure the battery isfully charged and check the cable connections(see Chapter 1). Make sure all connectors areclean, with no broken or loose terminals.

12•10 Wiring diagrams

Typical starting, charging, horn, hazard flasher and direction indicators (1 of 4)

Wiring diagrams 12•11

12Typical headlights/foglights and interior lights (2 of 4)


Typical check control, electric mirrors, stop and parking light (3 of 4)


12

Typical instrument cluster and cigar lighter (4 of 4)


Typical Motronic system wiring diagram (1 of 2)


12

Typical Motronic system wiring diagram (2 of 2)


Key to Motronic engine control system wiring diagram

Key to cruise control system wiring diagram


12

Typical cruise control system wiring diagram


Typical wiring diagram for the central locking, burglar alarm, on-board computer, additional heater and digital clock (1 of 2)


12

Typical wiring diagram for the central locking, burglar alarm, on-board computer, additional heater and digital clock (2 of 2)


Key to wiring diagram for the central locking, burglar alarm, on-board computer, additional heater and digital clock


12

Typical headlight washer system wiring diagram


Key to electric window system wiring diagram

Key to headlight washer system wiring diagram


12

Typical electric window system wiring diagram


Typical heating and air conditioning system wiring diagram


12

Key to wiring diagram for heated seats

Key to air conditioning system wiring diagram


Typical heated seats wiring diagram


12

Key to wiring diagram for memory power seats


Typical wiring diagram for power seats with memory (1 of 2)


12

Typical wiring diagram for power seats with memory (2 of 2)


Typical wiring diagram for power seats without memory


12

Key to wiring diagram for power seats without memory

Key to radio wiring diagram


Typical radio wiring diagram – early models shown


12

Typical L-Jetronic system wiring diagram

REF•1

REF

MOT Test ChecksThis is a guide to getting your vehicle through the MOT test.

Obviously it will not be possible to examine the vehicle to the samestandard as the professional MOT tester. However, working throughthe following checks will enable you to identify any problem areasbefore submitting the vehicle for the test.

Where a testable component is in borderline condition, the testerhas discretion in deciding whether to pass or fail it. The basis of suchdiscretion is whether the tester would be happy for a close relative orfriend to use the vehicle with the component in that condition. If thevehicle presented is clean and evidently well cared for, the tester maybe more inclined to pass a borderline component than if the vehicle isscruffy and apparently neglected.

It has only been possible to summarise the test requirements here,based on the regulations in force at the time of printing. Test standardsare becoming increasingly stringent, although there are someexemptions for older vehicles. For full details obtain a copy of the Haynespublication Pass the MOT! (available from stockists of Haynes manuals).

An assistant will be needed to help carry out some of these checks.

The checks have been sub-divided into four categories, as follows:

HandbrakeM Test the operation of the handbrake.Excessive travel (too many clicks) indicatesincorrect brake or cable adjustment.M Check that the handbrake cannot bereleased by tapping the lever sideways. Checkthe security of the lever mountings.

FootbrakeM Depress the brake pedal and check that itdoes not creep down to the floor, indicating amaster cylinder fault. Release the pedal, waita few seconds, then depress it again. If thepedal travels nearly to the floor before firmresistance is felt, brake adjustment or repair isnecessary. If the pedal feels spongy, there isair in the hydraulic system which must beremoved by bleeding.

M Check that the brake pedal is secure and ingood condition. Check also for signs of fluidleaks on the pedal, floor or carpets, whichwould indicate failed seals in the brake mastercylinder.M Check the servo unit (when applicable) byoperating the brake pedal several times, thenkeeping the pedal depressed and starting theengine. As the engine starts, the pedal willmove down slightly. If not, the vacuum hose orthe servo itself may be faulty.

Steering wheel and column M Examine the steering wheel for fractures orlooseness of the hub, spokes or rim. M Move the steering wheel from side to sideand then up and down. Check that the steering wheel is not loose on the column,indicating wear or a loose retaining nut.Continue moving the steering wheel as before,but also turn it slightly from left to right. M Check that the steering wheel is not looseon the column, and that there is no abnormal

movement of the steering wheel, indicatingwear in the column support bearings or couplings.

Windscreen and mirrors M The windscreen must be free of cracks orother significant damage within the driver’sfield of view. (Small stone chips areacceptable.) Rear view mirrors must besecure, intact, and capable of being adjusted.

1Checks carried outFROM THE DRIVER’S SEAT

1Checks carried outFROM THE DRIVER’SSEAT

2Checks carried outWITH THE VEHICLEON THE GROUND

3Checks carried outWITH THE VEHICLERAISED AND THEWHEELS FREE TOTURN

4Checks carried out onYOUR VEHICLE’SEXHAUST EMISSIONSYSTEM

REF•2 MOT Test Checks

Seat belts and seats Note: The following checks are applicable toall seat belts, front and rear.

M Examine the webbing of all the belts(including rear belts if fitted) for cuts, seriousfraying or deterioration. Fasten and unfasteneach belt to check the buckles. If applicable,check the retracting mechanism. Check thesecurity of all seat belt mountings accessiblefrom inside the vehicle.M The front seats themselves must besecurely attached and the backrests mustlock in the upright position.

Doors M Both front doors must be able to be openedand closed from outside and inside, and mustlatch securely when closed.

Vehicle identificationM Number plates must be in good condition,secure and legible, with letters and numberscorrectly spaced – spacing at (A) should betwice that at (B).

M The VIN plate and/or homologation platemust be legible.

Electrical equipmentM Switch on the ignition and check the operation of the horn.M Check the windscreen washers and wipers,examining the wiper blades; renew damagedor perished blades. Also check the operationof the stop-lights.

M Check the operation of the sidelights andnumber plate lights. The lenses and reflectorsmust be secure, clean and undamaged. M Check the operation and alignment of theheadlights. The headlight reflectors must notbe tarnished and the lenses must beundamaged.M Switch on the ignition and check the operation of the direction indicators (includingthe instrument panel tell-tale) and the hazardwarning lights. Operation of the sidelights andstop-lights must not affect the indicators - if itdoes, the cause is usually a bad earth at therear light cluster.M Check the operation of the rear foglight(s),including the warning light on the instrumentpanel or in the switch.

FootbrakeM Examine the master cylinder, brake pipesand servo unit for leaks, loose mountings, corrosion or other damage.

M The fluid reservoir must be secure and thefluid level must be between the upper (A) andlower (B) markings.

M Inspect both front brake flexible hoses forcracks or deterioration of the rubber. Turn thesteering from lock to lock, and ensure that thehoses do not contact the wheel, tyre, or anypart of the steering or suspension mechanism.With the brake pedal firmly depressed, checkthe hoses for bulges or leaks under pressure.

Steering and suspensionM Have your assistant turn the steering wheelfrom side to side slightly, up to the point wherethe steering gear just begins to transmit thismovement to the roadwheels. Check forexcessive free play between the steeringwheel and the steering gear, indicating wear orinsecurity of the steering column joints, thecolumn-to-steering gear coupling, or thesteering gear itself.M Have your assistant turn the steering wheelmore vigorously in each direction, so that theroadwheels just begin to turn. As this is done,examine all the steering joints, linkages,fittings and attachments. Renew anycomponent that shows signs of wear or damage. On vehicles with power steering,check the security and condition of the steering pump, drivebelt and hoses.M Check that the vehicle is standing level,and at approximately the correct ride height.

Shock absorbersM Depress each corner of the vehicle in turn,then release it. The vehicle should rise andthen settle in its normal position. If the vehiclecontinues to rise and fall, the shock absorberis defective. A shock absorber which hasseized will also cause the vehicle to fail.

2Checks carried outWITH THE VEHICLE ON THEGROUND

REF•3

REF

MOT Test Checks

Exhaust systemM Start the engine. With your assistant holding a rag over the tailpipe, check theentire system for leaks. Repair or renewleaking sections.

Jack up the front and rear of the vehicle,and securely support it on axle stands.Position the stands clear of the suspensionassemblies. Ensure that the wheels areclear of the ground and that the steeringcan be turned from lock to lock.

Steering mechanism M Have your assistant turn the steering fromlock to lock. Check that the steering turnssmoothly, and that no part of the steeringmechanism, including a wheel or tyre, foulsany brake hose or pipe or any part of the bodystructure.M Examine the steering rack rubber gaitersfor damage or insecurity of the retaining clips.If power steering is fitted, check for signs ofdamage or leakage of the fluid hoses, pipes orconnections. Also check for excessivestiffness or binding of the steering, a missingsplit pin or locking device, or severe corrosionof the body structure within 30 cm of anysteering component attachment point.

Front and rear suspension andwheel bearings M Starting at the front right-hand side, graspthe roadwheel at the 3 o’clock and 9 o’clockpositions and shake it vigorously. Check forfree play or insecurity at the wheel bearings,suspension balljoints, or suspension mount-ings, pivots and attachments.M Now grasp the wheel at the 12 o’clock and6 o’clock positions and repeat the previousinspection. Spin the wheel, and check forroughness or tightness of the front wheelbearing.

M If excess free play is suspected at acomponent pivot point, this can be confirmedby using a large screwdriver or similar tool andlevering between the mounting and thecomponent attachment. This will confirmwhether the wear is in the pivot bush, itsretaining bolt, or in the mounting itself (the boltholes can often become elongated).

M Carry out all the above checks at the otherfront wheel, and then at both rear wheels.

Springs and shock absorbers M Examine the suspension struts (whenapplicable) for serious fluid leakage, corrosion,or damage to the casing. Also check thesecurity of the mounting points.M If coil springs are fitted, check that thespring ends locate in their seats, and that thespring is not corroded, cracked or broken.M If leaf springs are fitted, check that allleaves are intact, that the axle is securelyattached to each spring, and that there is nodeterioration of the spring eye mountings,bushes, and shackles.

M The same general checks apply to vehiclesfitted with other suspension types, such astorsion bars, hydraulic displacer units, etc.Ensure that all mountings and attachments aresecure, that there are no signs of excessivewear, corrosion or damage, and (on hydraulictypes) that there are no fluid leaks or damagedpipes.M Inspect the shock absorbers for signs ofserious fluid leakage. Check for wear of themounting bushes or attachments, or damageto the body of the unit.

Driveshafts(fwd vehicles only)M Rotate each front wheel in turn and inspectthe constant velocity joint gaiters for splits ordamage. Also check that each driveshaft isstraight and undamaged.

Braking system M If possible without dismantling, checkbrake pad wear and disc condition. Ensurethat the friction lining material has not wornexcessively, (A) and that the discs are notfractured, pitted, scored or badly worn (B).

M Examine all the rigid brake pipesunderneath the vehicle, and the flexiblehose(s) at the rear. Look for corrosion, chafingor insecurity of the pipes, and for signs ofbulging under pressure, chafing, splits ordeterioration of the flexible hoses.M Look for signs of fluid leaks at the brakecalipers or on the brake backplates. Repair orrenew leaking components.M Slowly spin each wheel, while yourassistant depresses and releases thefootbrake. Ensure that each brake is operatingand does not bind when the pedal is released.

3Checks carried outWITH THE VEHICLE RAISEDAND THE WHEELS FREE TOTURN

REF•4 MOT Test Checks

M Examine the handbrake mechanism,checking for frayed or broken cables,excessive corrosion, or wear or insecurity ofthe linkage. Check that the mechanism workson each relevant wheel, and releases fully,without binding.M It is not possible to test brake efficiencywithout special equipment, but a road test canbe carried out later to check that the vehiclepulls up in a straight line.

Fuel and exhaust systemsM Inspect the fuel tank (including the fillercap), fuel pipes, hoses and unions. Allcomponents must be secure and free fromleaks.M Examine the exhaust system over its entirelength, checking for any damaged, broken ormissing mountings, security of the retainingclamps and rust or corrosion.

Wheels and tyres M Examine the sidewalls and tread area ofeach tyre in turn. Check for cuts, tears, lumps,bulges, separation of the tread, and exposureof the ply or cord due to wear or damage.Check that the tyre bead is correctly seatedon the wheel rim, that the valve is sound and

properly seated, and that the wheel is notdistorted or damaged. M Check that the tyres are of the correct sizefor the vehicle, that they are of the same sizeand type on each axle, and that the pressuresare correct.M Check the tyre tread depth. The legalminimum at the time of writing is 1.6 mm overat least three-quarters of the tread width.Abnormal tread wear may indicate incorrectfront wheel alignment.

Body corrosionM Check the condition of the entire vehiclestructure for signs of corrosion in load-bearingareas. (These include chassis box sections,side sills, cross-members, pillars, and allsuspension, steering, braking system andseat belt mountings and anchorages.) Anycorrosion which has seriously reduced thethickness of a load-bearing area is likely tocause the vehicle to fail. In this caseprofessional repairs are likely to be needed.M Damage or corrosion which causes sharpor otherwise dangerous edges to be exposedwill also cause the vehicle to fail.

Petrol modelsM Have the engine at normal operatingtemperature, and make sure that it is in goodtune (ignition system in good order, air filterelement clean, etc).M Before any measurements are carried out,raise the engine speed to around 2500 rpm,and hold it at this speed for 20 seconds. Allow

the engine speed to return to idle, and watchfor smoke emissions from the exhausttailpipe. If the idle speed is obviously muchtoo high, or if dense blue or clearly-visibleblack smoke comes from the tailpipe for morethan 5 seconds, the vehicle will fail. As a ruleof thumb, blue smoke signifies oil being burnt(engine wear) while black smoke signifiesunburnt fuel (dirty air cleaner element, or othercarburettor or fuel system fault).M An exhaust gas analyser capable ofmeasuring carbon monoxide (CO) andhydrocarbons (HC) is now needed. If such aninstrument cannot be hired or borrowed, alocal garage may agree to perform the checkfor a small fee.

CO emissions (mixture)M At the time of writing, the maximum COlevel at idle is 3.5% for vehicles first used afterAugust 1986 and 4.5% for older vehicles.From January 1996 a much tighter limit(around 0.5%) applies to catalyst-equippedvehicles first used from August 1992. If theCO level cannot be reduced far enough topass the test (and the fuel and ignitionsystems are otherwise in good condition) thenthe carburettor is badly worn, or there is someproblem in the fuel injection system orcatalytic converter (as applicable).

HC emissionsM With the CO emissions within limits, HCemissions must be no more than 1200 ppm(parts per million). If the vehicle fails this testat idle, it can be re-tested at around 2000 rpm;if the HC level is then 1200 ppm or less, thiscounts as a pass.M Excessive HC emissions can be caused byoil being burnt, but they are more likely to bedue to unburnt fuel.

Diesel modelsM The only emission test applicable to Dieselengines is the measuring of exhaust smokedensity. The test involves accelerating theengine several times to its maximumunloaded speed.

Note: It is of the utmost importance that theengine timing belt is in good condition beforethe test is carried out.

M Excessive smoke can be caused by a dirtyair cleaner element. Otherwise, professionaladvice may be needed to find the cause.

4Checks carried out onYOUR VEHICLE’S EXHAUSTEMISSION SYSTEM

IntroductionA selection of good tools is a fundamental

requirement for anyone contemplating themaintenance and repair of a motor vehicle.For the owner who does not possess any,their purchase will prove a considerableexpense, offsetting some of the savings madeby doing-it-yourself. However, provided thatthe tools purchased meet the relevant nationalsafety standards and are of good quality, theywill last for many years and prove anextremely worthwhile investment.

To help the average owner to decide whichtools are needed to carry out the various tasksdetailed in this manual, we have compiledthree lists of tools under the followingheadings: Maintenance and minor repair,Repair and overhaul, and Special. Newcomersto practical mechanics should start off withthe Maintenance and minor repair tool kit, andconfine themselves to the simpler jobs aroundthe vehicle. Then, as confidence andexperience grow, more difficult tasks can beundertaken, with extra tools being purchasedas, and when, they are needed. In this way, aMaintenance and minor repair tool kit can bebuilt up into a Repair and overhaul tool kit overa considerable period of time, without anymajor cash outlays. The experienced do-it-yourselfer will have a tool kit good enough formost repair and overhaul procedures, and willadd tools from the Special category when it isfelt that the expense is justified by the amountof use to which these tools will be put.

Maintenance and minor repair tool kit

The tools given in this list should beconsidered as a minimum requirement ifroutine maintenance, servicing and minorrepair operations are to be undertaken. Werecommend the purchase of combinationspanners (ring one end, open-ended theother); although more expensive than open-ended ones, they do give the advantages ofboth types of spanner.M Combination spanners:

Metric - 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 21, 22, 24 & 26 mm

M Adjustable spanner - 35 mm jaw (approx)M Transmission drain plug key (Allen type)M Set of feeler gaugesM Spark plug spanner (with rubber insert)M Spark plug gap adjustment toolM Brake bleed nipple spannerM Screwdrivers:

Flat blade - approx 100 mm long x 6 mm diaCross blade - approx 100 mm long x 6 mm dia

M Combination pliersM Hacksaw (junior)M Tyre pumpM Tyre pressure gaugeM Oil canM Oil filter removal toolM Fine emery clothM Wire brush (small)M Funnel (medium size)

Repair and overhaul tool kitThese tools are virtually essential for

anyone undertaking any major repairs to amotor vehicle, and are additional to thosegiven in the Maintenance and minor repair list.Included in this list is a comprehensive set ofsockets. Although these are expensive, theywill be found invaluable as they are soversatile - particularly if various drives areincluded in the set. We recommend the half-inch square-drive type, as this can be usedwith most proprietary torque wrenches. If youcannot afford a socket set, even boughtpiecemeal, then inexpensive tubular boxspanners are a useful alternative.

The tools in this list will occasionally needto be supplemented by tools from the Speciallist:M Sockets (or box spanners) to cover range in

previous list M Reversible ratchet drive (for use with

sockets) (see illustration)M Extension piece, 250 mm (for use with

sockets)M Universal joint (for use with sockets)M Torque wrench (for use with sockets)M Self-locking gripsM Ball pein hammerM Soft-faced mallet (plastic/aluminium or

rubber)M Screwdrivers:

Flat blade - long & sturdy, short (chubby), and narrow (electrician’s) typesCross blade - Long & sturdy, and short(chubby) types

M Pliers:Long-nosedSide cutters (electrician’s)Circlip (internal and external)

M Cold chisel - 25 mmM ScriberM ScraperM Centre-punchM Pin punchM HacksawM Brake hose clampM Brake/clutch bleeding kitM Selection of twist drills

M Steel rule/straight-edgeM Allen keys (inc. splined/Torx type) (see

illustrations)M Selection of filesM Wire brushM Axle standsM Jack (strong trolley or hydraulic type)M Light with extension lead

Special toolsThe tools in this list are those which are not

used regularly, are expensive to buy, or whichneed to be used in accordance with theirmanufacturers’ instructions. Unless relativelydifficult mechanical jobs are undertakenfrequently, it will not be economic to buymany of these tools. Where this is the case,you could consider clubbing together withfriends (or joining a motorists’ club) to make ajoint purchase, or borrowing the tools againsta deposit from a local garage or tool hirespecialist. It is worth noting that many of thelarger DIY superstores now carry a largerange of special tools for hire at modest rates.

The following list contains only those toolsand instruments freely available to the public,and not those special tools produced by thevehicle manufacturer specifically for its dealernetwork. You will find occasional referencesto these manufacturers’ special tools in thetext of this manual. Generally, an alternativemethod of doing the job without the vehiclemanufacturers’ special tool is given. However,sometimes there is no alternative to usingthem. Where this is the case and the relevanttool cannot be bought or borrowed, you willhave to entrust the work to a franchisedgarage.M Valve spring compressor (see illustration)M Valve grinding toolM Piston ring compressor (see illustration)M Piston ring removal/installation tool (see

illustration)M Cylinder bore hone (see illustration)M Balljoint separatorM Coil spring compressors (where applicable)M Two/three-legged hub and bearing puller

(see illustration)

REF•5

REF

Tools and Working Facilities

Sockets and reversible ratchet drive Spline bit set

REF•6 Tools and Working Facilities

Compression testing gauge Clutch plate alignment set Brake shoe steady spring cup removal tool

Micrometer set Vernier calipers Dial test indicator and magnetic stand

Piston ring removal/installation tool Cylinder bore hone Three-legged hub and bearing puller

Valve spring compressor Piston ring compressorSpline key set

REF•7

REF

Tools and Working FacilitiesM Impact screwdriverM Micrometer and/or vernier calipers (see

illustrations)M Dial gauge (see illustration)M Universal electrical multi-meterM Cylinder compression gauge

(see illustration)M Clutch plate alignment set (see illustration)M Brake shoe steady spring cup removal tool

(see illustration)M Bush and bearing removal/installation set

(see illustration)M Stud extractors (see illustration)M Tap and die set (see illustration)M Lifting tackleM Trolley jack

Buying toolsFor practically all tools, a tool factor is the

best source, since he will have a verycomprehensive range compared with theaverage garage or accessory shop. Havingsaid that, accessory shops often offerexcellent quality tools at discount prices, so itpays to shop around.

Remember, you don’t have to buy the mostexpensive items on the shelf, but it is alwaysadvisable to steer clear of the very cheaptools. There are plenty of good tools around at

reasonable prices, but always aim topurchase items which meet the relevantnational safety standards. If in doubt, ask theproprietor or manager of the shop for advicebefore making a purchase.

Care and maintenance of toolsHaving purchased a reasonable tool kit, it is

necessary to keep the tools in a clean andserviceable condition. After use, always wipeoff any dirt, grease and metal particles using aclean, dry cloth, before putting the tools away.Never leave them lying around after they havebeen used. A simple tool rack on the garageor workshop wall for items such asscrewdrivers and pliers is a good idea. Storeall normal spanners and sockets in a metalbox. Any measuring instruments, gauges,meters, etc, must be carefully stored wherethey cannot be damaged or become rusty.

Take a little care when tools are used.Hammer heads inevitably become marked,and screwdrivers lose the keen edge on theirblades from time to time. A little timelyattention with emery cloth or a file will soonrestore items like this to a good serviceablefinish.

Working facilitiesNot to be forgotten when discussing tools

is the workshop itself. If anything more thanroutine maintenance is to be carried out,some form of suitable working area becomesessential.

It is appreciated that many an owner-mechanic is forced by circumstances toremove an engine or similar item without thebenefit of a garage or workshop. Having donethis, any repairs should always be done underthe cover of a roof.

Wherever possible, any dismantling shouldbe done on a clean, flat workbench or table ata suitable working height.

Any workbench needs a vice; one with ajaw opening of 100 mm is suitable for mostjobs. As mentioned previously, some cleandry storage space is also required for tools, aswell as for any lubricants, cleaning fluids,touch-up paints and so on, which becomenecessary.

Another item which may be required, andwhich has a much more general usage, is anelectric drill with a chuck capacity of at least 8mm. This, together with a good range of twistdrills, is virtually essential for fittingaccessories.

Last, but not least, always keep a supply ofold newspapers and clean, lint-free ragsavailable, and try to keep any working area asclean as possible.

Bush and bearing removal/installation set Stud extractor set Tap and die set

REF•8 General Repair ProceduresWhenever servicing, repair or overhaul work

is carried out on the car or its components,observe the following procedures andinstructions. This will assist in carrying out theoperation efficiently and to a professionalstandard of workmanship.

Joint mating faces and gasketsWhen separating components at their

mating faces, never insert screwdrivers orsimilar implements into the joint between thefaces in order to prise them apart. This cancause severe damage which results in oilleaks, coolant leaks, etc upon reassembly.Separation is usually achieved by tappingalong the joint with a soft-faced hammer inorder to break the seal. However, note thatthis method may not be suitable wheredowels are used for component location.

Where a gasket is used between the matingfaces of two components, a new one must befitted on reassembly; fit it dry unless otherwisestated in the repair procedure. Make sure thatthe mating faces are clean and dry, with alltraces of old gasket removed. When cleaning ajoint face, use a tool which is unlikely to scoreor damage the face, and remove any burrs ornicks with an oilstone or fine file.

Make sure that tapped holes are cleanedwith a pipe cleaner, and keep them free ofjointing compound, if this is being used,unless specifically instructed otherwise.

Ensure that all orifices, channels or pipesare clear, and blow through them, preferablyusing compressed air.

Oil sealsOil seals can be removed by levering them

out with a wide flat-bladed screwdriver orsimilar implement. Alternatively, a number ofself-tapping screws may be screwed into theseal, and these used as a purchase for pliers orsome similar device in order to pull the seal free.

Whenever an oil seal is removed from itsworking location, either individually or as partof an assembly, it should be renewed.

The very fine sealing lip of the seal is easilydamaged, and will not seal if the surface itcontacts is not completely clean and free fromscratches, nicks or grooves. If the originalsealing surface of the component cannot berestored, and the manufacturer has not madeprovision for slight relocation of the sealrelative to the sealing surface, the componentshould be renewed.

Protect the lips of the seal from any surfacewhich may damage them in the course offitting. Use tape or a conical sleeve wherepossible. Lubricate the seal lips with oil beforefitting and, on dual-lipped seals, fill the spacebetween the lips with grease.

Unless otherwise stated, oil seals must befitted with their sealing lips toward thelubricant to be sealed.

Use a tubular drift or block of wood of theappropriate size to install the seal and, if theseal housing is shouldered, drive the sealdown to the shoulder. If the seal housing is

unshouldered, the seal should be fitted withits face flush with the housing top face (unlessotherwise instructed).

Screw threads and fasteningsSeized nuts, bolts and screws are quite a

common occurrence where corrosion has setin, and the use of penetrating oil or releasingfluid will often overcome this problem if theoffending item is soaked for a while beforeattempting to release it. The use of an impactdriver may also provide a means of releasingsuch stubborn fastening devices, when usedin conjunction with the appropriatescrewdriver bit or socket. If none of thesemethods works, it may be necessary to resortto the careful application of heat, or the use ofa hacksaw or nut splitter device.

Studs are usually removed by locking twonuts together on the threaded part, and thenusing a spanner on the lower nut to unscrewthe stud. Studs or bolts which have broken offbelow the surface of the component in whichthey are mounted can sometimes be removedusing a stud extractor. Always ensure that ablind tapped hole is completely free from oil,grease, water or other fluid before installingthe bolt or stud. Failure to do this could causethe housing to crack due to the hydraulicaction of the bolt or stud as it is screwed in.

When tightening a castellated nut to accepta split pin, tighten the nut to the specifiedtorque, where applicable, and then tightenfurther to the next split pin hole. Never slackenthe nut to align the split pin hole, unless statedin the repair procedure.

When checking or retightening a nut or boltto a specified torque setting, slacken the nutor bolt by a quarter of a turn, and thenretighten to the specified setting. However,this should not be attempted where angulartightening has been used.

For some screw fastenings, notablycylinder head bolts or nuts, torque wrenchsettings are no longer specified for the latterstages of tightening, “angle-tightening” beingcalled up instead. Typically, a fairly low torquewrench setting will be applied to thebolts/nuts in the correct sequence, followedby one or more stages of tightening throughspecified angles.

Locknuts, locktabs and washersAny fastening which will rotate against a

component or housing during tighteningshould always have a washer between it andthe relevant component or housing.

Spring or split washers should always berenewed when they are used to lock a criticalcomponent such as a big-end bearingretaining bolt or nut. Locktabs which arefolded over to retain a nut or bolt shouldalways be renewed.

Self-locking nuts can be re-used in non-critical areas, providing resistance can be feltwhen the locking portion passes over the boltor stud thread. However, it should be notedthat self-locking stiffnuts tend to lose their

effectiveness after long periods of use, andshould then be renewed as a matter of course.

Split pins must always be replaced withnew ones of the correct size for the hole.

When thread-locking compound is foundon the threads of a fastener which is to be re-used, it should be cleaned off with a wirebrush and solvent, and fresh compoundapplied on reassembly.

Special toolsSome repair procedures in this manual

entail the use of special tools such as a press,two or three-legged pullers, spring com-pressors, etc. Wherever possible, suitablereadily-available alternatives to the manu-facturer’s special tools are described, and areshown in use. In some instances, where noalternative is possible, it has been necessaryto resort to the use of a manufacturer’s tool,and this has been done for reasons of safetyas well as the efficient completion of the repairoperation. Unless you are highly-skilled andhave a thorough understanding of theprocedures described, never attempt tobypass the use of any special tool when theprocedure described specifies its use. Notonly is there a very great risk of personalinjury, but expensive damage could becaused to the components involved.

Environmental considerationsWhen disposing of used engine oil, brake

fluid, antifreeze, etc, give due consideration toany detrimental environmental effects. Do not,for instance, pour any of the above liquidsdown drains into the general sewage system,or onto the ground to soak away. Many localcouncil refuse tips provide a facility for wasteoil disposal, as do some garages. If none ofthese facilities are available, consult your localEnvironmental Health Department, or theNational Rivers Authority, for further advice.

With the universal tightening-up of legis-lation regarding the emission of environmen-tally-harmful substances from motor vehicles,most vehicles have tamperproof devices fittedto the main adjustment points of the fuelsystem. These devices are primarily designedto prevent unqualified persons from adjustingthe fuel/air mixture, with the chance of aconsequent increase in toxic emissions. Ifsuch devices are found during servicing oroverhaul, they should, wherever possible, berenewed or refitted in accordance with themanufacturer’s requirements or currentlegislation.

Note: It isantisocial andillegal to dumpoil down thedrain. To findthe location ofyour local oilrecyclingbank, call thisnumber free.

REF•9

REF

Fault Finding

Enginemm Engine will not rotate when attempting to startmm Engine rotates, but will not startmm Engine hard to start when coldmm Engine hard to start when hotmm Starter motor noisy or excessively-rough in engagementmm Engine starts, but stops immediatelymm Oil puddle under enginemm Engine idles erraticallymm Engine misses at idle speedmm Engine misses throughout driving speed rangemm Engine misfires on accelerationmm Engine surges while holding accelerator steadymm Engine stallsmm Engine lacks powermm Engine backfiresmm Pinking or knocking engine sounds when accelerating

or driving uphillmm Engine runs with oil pressure light onmm Engine runs-on after switching off

Engine electrical systemmm Battery will not hold chargemm Ignition (no-charge) warning light fails to go outmm Ignition (no-charge) warning light fails to come on

when key is turned

Fuel systemmm Excessive fuel consumptionmm Fuel leakage and/or fuel odour

Cooling systemmm Overheatingmm Overcoolingmm External coolant leakagemm Internal coolant leakagemm Coolant lossmm Poor coolant circulation

Clutchmm Pedal travels to floor - no pressure or very little resistancemm Fluid in area of master cylinder dust cover and on pedalmm Fluid on slave cylindermm Pedal feels “spongy” when depressedmm Unable to select gearsmm Clutch slips (engine speed increases with no increase in

vehicle speed)mm Grabbing (chattering) as clutch is engagedmm Noise in clutch areamm Clutch pedal stays on floormm High pedal effort

Manual transmissionmm Vibrationmm Noisy in neutral with engine runningmm Noisy in one particular gearmm Noisy in all gearsmm Slips out of gearmm Leaks lubricant

Automatic transmissionmm Fluid leakagemm Transmission fluid brown, or has a burned smellmm General shift mechanism problemsmm Transmission will not kickdown with accelerator pedal

pressed to the floormm Engine will start in gears other than Park or Neutralmm Transmission slips, shifts roughly, is noisy, or has no drive

in forward or reverse gears

Brakesmm Vehicle pulls to one side during brakingmm Noise (high-pitched squeal) when the brakes are appliedmm Brake vibration (pedal pulsates)mm Excessive pedal effort required to stop vehiclemm Excessive brake pedal travelmm Dragging brakesmm Grabbing or uneven braking actionmm Brake pedal feels “spongy” when depressedmm Brake pedal travels to the floor with little resistancemm Handbrake does not hold

Suspension and steeringmm Vehicle pulls to one sidemm Abnormal or excessive tyre wearmm Wheel makes a “thumping” noisemm Shimmy, shake or vibrationmm High steering effortmm Poor steering self-centringmm Abnormal noise at the front endmm Wandering or poor steering stabilitymm Erratic steering when brakingmm Excessive pitching and/or rolling around corners or

during brakingmm Suspension bottomsmm Unevenly-worn tyresmm Excessive tyre wear on outside edgemm Excessive tyre wear on inside edgemm Tyre tread worn in one placemm Excessive play or looseness in steering systemmm Rattling or clicking noise in steering gear

REF•10 Fault Finding

Engine will not rotate when attempting to startmm Battery terminal connections loose or corroded (Chapter 1).mm Battery discharged or faulty (Chapter 1).mm Automatic transmission not completely engaged in Park (Chap-

ter 7B) or (on models with a clutch switch) clutch not completelydepressed (Chapter 8).

mm Broken, loose or disconnected wiring in the starting circuit(Chapters 5 and 12).

mm Starter motor pinion jammed in flywheel ring gear (Chapter 5).mm Starter solenoid faulty (Chapter 5).mm Starter motor faulty (Chapter 5).mm Ignition switch faulty (Chapter 12).mm Starter pinion or flywheel teeth worn or broken (Chapter 5).mm Engine internal problem (Chapter 2B).

Engine rotates, but will not startmm Fuel tank empty.mm Battery discharged (engine rotates slowly) (Chapter 5).mm Battery terminal connections loose or corroded (Chapter 1).mm Leaking fuel injector(s), faulty fuel pump, pressure regulator, etc

(Chapter 4).mm Fuel not reaching fuel injection system or carburettor (Chapter 4).mm Ignition components damp or damaged (Chapter 5).mm Fuel injector stuck open (Chapter 4).mm Worn, faulty or incorrectly-gapped spark plugs (Chapter 1).mm Broken, loose or disconnected wiring in the starting circuit

(Chapter 5).mm Loose distributor mounting bolts causing ignition timing to wander

(Chapters 1 and 5).mm Broken, loose or disconnected wires at the ignition coil, or faulty

coil (Chapter 5).

Engine hard to start when coldmm Battery discharged (Chapter 1).mm Fuel system malfunctioning (Chapter 4).mm Injector(s) leaking or carburettor automatic choke faulty (Chap-

ter 4).mm Distributor rotor carbon-tracked (Chapter 5).

Engine hard to start when hotmm Air filter element clogged (Chapter 1).mm Fuel not reaching the fuel injection system or carburettor (Chap-

ter 4).mm Corroded battery connections, especially earth (negative)

connection (Chapter 1).

Starter motor noisy or excessively-rough inengagementmm Pinion or flywheel gear teeth worn or broken (Chapter 5).mm Starter motor mounting bolts loose or missing (Chapter 5).

Engine starts, but stops immediatelymm Loose or faulty electrical connections at distributor, coil or

alternator (Chapter 5).mm Insufficient fuel reaching the fuel injector(s) or carburettor

(Chapters 1 and 4).mm Damaged fuel injection system speed sensors (Chapter 5).mm Faulty fuel injection relays (Chapter 5).

Oil puddle under enginemm Oil sump gasket and/or sump drain plug seal leaking (Chapter 2).mm Oil pressure sender unit leaking (Chapter 2).mm Valve cover gaskets leaking (Chapter 2).mm Engine oil seals leaking (Chapter 2).

Engine idles erraticallymm Vacuum leakage (Chapter 4).mm Air filter element clogged (Chapter 1).mm Fuel pump not delivering sufficient fuel to the fuel injection system

or carburettor (Chapter 4).mm Leaking head gasket (Chapter 2).mm Timing belt/chain and/or sprockets worn (Chapter 2).mm Camshaft lobes worn (Chapter 2).mm Faulty charcoal canister, where fitted (Chapter 6).

This Section provides an easy-reference guide to the morecommon problems which may occur during the operation of yourvehicle. These problems and their possible causes are grouped underheadings denoting various components or systems, such as Engine,Cooling system, etc. They also refer you to the Chapter and/orSection which deals with the problem.

Remember that successful fault diagnosis is not a mysteriousblack art practised only by professional mechanics. It is simply theresult of the right knowledge combined with an intelligent, systematicapproach to the problem. Always work by a process of elimination,starting with the simplest solution and working through to the most

complex - and never overlook the obvious. Anyone can run the fueltank dry or leave the lights on overnight, so don’t assume that you areexempt from such oversights.

Finally, always establish a clear idea of why a problem hasoccurred, and take steps to ensure that it doesn’t happen again. If theelectrical system fails because of a poor connection, check all otherconnections in the system to make sure that they don’t fail as well. If aparticular fuse continues to blow, find out why - don’t just renew onefuse after another. Remember, failure of a small component can oftenbe indicative of potential failure or incorrect functioning of a moreimportant component or system.

Engine

REF•11

REF

Fault FindingEngine misses at idle speedmm Spark plugs worn or incorrectly-gapped (Chapter 1).mm Faulty spark plug HT leads (Chapter 1).mm Vacuum leaks (Chapter 1).mm Incorrect ignition timing (Chapter 5).mm Uneven or low compression (Chapter 2).mm Faulty charcoal canister, where fitted (Chapter 6).

Engine misses throughout driving speed rangemm Fuel filter clogged and/or impurities in the fuel system (Chapter 1).mm Low fuel output at the injectors, or partially-blocked carburettor

jets (Chapter 4).mm Faulty or incorrectly-gapped spark plugs (Chapter 1).mm Incorrect ignition timing (Chapter 5).mm Cracked distributor cap, disconnected distributor HT leads, or

damaged distributor components (Chapter 1).mm Faulty spark plug HT leads (Chapter 1).mm Faulty emission system components (Chapter 6).mm Low or uneven cylinder compression pressures (Chapter 2).mm Weak or faulty ignition system (Chapter 5).mm Vacuum leak in fuel injection system, intake manifold or vacuum

hoses (Chapter 4).

Engine misfires on accelerationmm Spark plugs fouled (Chapter 1).mm Fuel injection system or carburettor malfunctioning (Chapter 4).mm Fuel filter clogged (Chapters 1 and 4).mm Incorrect ignition timing (Chapter 5).mm Intake manifold air leak (Chapter 4).

Engine surges while holding accelerator steadymm Intake air leak (Chapter 4).mm Fuel pump faulty (Chapter 4).mm Loose fuel injector harness connections (Chapters 4 and 6).mm Defective ECU (Chapter 5).

Engine lacks powermm Incorrect ignition timing (Chapter 5).mm Excessive play in distributor shaft (Chapter 5).mm Worn rotor, distributor cap or HT leads (Chapters 1 and 5).mm Faulty or incorrectly-gapped spark plugs (Chapter 1).mm Fuel injection system or carburettor malfunctioning (Chapter 4).mm Faulty coil (Chapter 5).mm Brakes binding (Chapter 1).mm Automatic transmission fluid level incorrect (Chapter 1).mm Clutch slipping (Chapter 8).mm Fuel filter clogged and/or impurities in the fuel system (Chapter 1).mm Emission control system not functioning properly (Chapter 6).mm Low or uneven cylinder compression pressures (Chapter 2).

Engine stallsmm Idle speed incorrect (Chapter 1).mm Fuel filter clogged and/or water and impurities in the fuel system

(Chapter 1).mm Distributor components damp or damaged (Chapter 5).mm Faulty emissions system components (Chapter 6).mm Faulty or incorrectly-gapped spark plugs (Chapter 1).mm Faulty spark plug HT leads (Chapter 1).mm Vacuum leak in the fuel injection system, intake manifold or

vacuum hoses (Chapter 4).

Engine backfiresmm Emissions system not functioning properly (Chapter 6).mm Ignition timing incorrect (Chapter 5).mm Faulty secondary ignition system (cracked spark plug insulator,

faulty plug HT leads, distributor cap and/or rotor) (Chapters 1 and 5).mm Fuel injection system or carburettor malfunctioning (Chapter 4).mm Vacuum leak at fuel injector(s), intake manifold or vacuum hoses

(Chapter 4).mm Valve clearances incorrect (Chapter 1), or valve(s) sticking or

damaged (Chapter 2).

Pinking or knocking engine sounds whenaccelerating or driving uphillmm Incorrect grade of fuel.mm Ignition timing incorrect (Chapter 5).mm Fuel injection system or carburettor in need of adjustment (Chap-

ter 4).mm Damaged spark plugs or HT leads, or incorrect type fitted (Chapter 1).mm Worn or damaged distributor components (Chapter 5).mm Faulty emission system (Chapter 6).mm Vacuum leak (Chapter 4).

Engine runs with oil pressure light onCaution: Stop the engine immediately if the oilpressure light comes on and establish the cause.Running the engine while the oil pressure is low cancause severe damage.

mm Low oil level (Chapter 1).mm Idle speed too low (Chapter 1).mm Short-circuit in wiring (Chapter 12).mm Faulty oil pressure sender unit (Chapter 2).mm Worn engine bearings and/or oil pump (Chapter 2).

Engine runs-on after switching offmm Idle speed too high (Chapter 1).mm Excessive engine operating temperature (Chapter 3).mm Incorrect fuel octane grade.mm Spark plugs defective or incorrect grade (Chapter 1).

Engine electrical systemBattery will not hold chargemm Alternator drivebelt defective or not adjusted properly (Chapter 1).mm Electrolyte level low (Chapter 1).mm Battery terminals loose or corroded (Chapter 1).mm Alternator not charging properly (Chapter 5).mm Loose, broken or faulty wiring in the charging circuit (Chapter 5).mm Short in vehicle wiring (Chapters 5 and 12).mm Internally-defective battery (Chapters 1 and 5).mm Ignition (no-charge) warning light bulb blown - on some early

models (Chapter 5)

Ignition (no-charge) warning light fails to go outmm Faulty alternator or charging circuit (Chapter 5).mm Alternator drivebelt defective or out of adjustment (Chapter 1).mm Alternator voltage regulator inoperative (Chapter 5).

Ignition (no-charge) warning light fails to come onwhen key is turned

mm Warning light bulb defective (Chapter 12).mm Fault in the printed circuit, wiring or bulbholder (Chapter 12).


Fuel systemExcessive fuel consumptionmm Dirty or clogged air filter element (Chapter 1).mm Ignition timing incorrect (Chapter 5).mm Emissions system not functioning properly (Chapter 6).mm Fuel injection internal parts or carburettor jets excessively worn or

damaged (Chapter 4).mm Low tyre pressure or incorrect tyre size (Chapter 1).mm Unsympathetic driving style, or unfavourable conditions.

Fuel leakage and/or fuel odourWarning: Don’t drive the vehicle if a fuel leak issuspected. Leaking fuel in the engine compartmentcould catch fire.

mm Leak in a fuel feed or vent line (Chapter 4).mm Tank overfilled.mm Fuel injector or carburettor parts excessively worn, or fuel system

gaskets leaking (Chapter 4).

Cooling systemOverheatingmm Insufficient coolant in system (Chapter 1).mm Water pump drivebelt defective or out of adjustment (Chapter 1).mm Radiator matrix blocked, or grille restricted (Chapter 3).mm Thermostat faulty (Chapter 3).mm Radiator cap not maintaining proper pressure (Chapter 3).mm Ignition timing incorrect (Chapter 5).

Overcoolingmm Faulty thermostat (Chapter 3).

External coolant leakagemm Deteriorated/damaged hoses; loose clamps (Chapters 1 and 3).mm Water pump seal defective (Chapters 1 and 3).mm Leakage from radiator matrix, heater matrix or header tank

(Chapter 3).mm Radiator/engine block drain plugs or water jacket core plugs

leaking (Chapters 2 and 3).

Internal coolant leakagemm Leaking cylinder head gasket (Chapter 2).mm Cracked cylinder bore or cylinder head (Chapter 2).

Coolant lossmm Too much coolant in system (Chapter 1).mm Coolant boiling away because of overheating (see above).mm Internal or external leakage (see above).mm Faulty radiator cap (Chapter 3).

Poor coolant circulationmm Inoperative water pump (Chapter 3).mm Restriction in cooling system (Chapters 1 and 3).mm Water pump drivebelt defective/out of adjustment (Chapter 1).mm Thermostat sticking (Chapter 3).

ClutchPedal travels to floor - no pressure or very littleresistancemm Master or slave cylinder faulty (Chapter 8).mm Fluid line burst or leaking (Chapter 8).mm Connections leaking (Chapter 8).mm No fluid in reservoir (Chapter 1).mm If fluid is present in master cylinder dust cover, master cylinder rear

seal has failed (Chapter 8).mm Broken release bearing or fork (Chapter 8).

Fluid in area of master cylinder dust cover, and onpedalmm Rear seal failure in master cylinder (Chapter 8).

Fluid on slave cylindermm Slave cylinder plunger seal faulty (Chapter 8).

Pedal feels “spongy” when depressedmm Air in system (Chapter 8).

Unable to select gearsmm Faulty transmission (Chapter 7).mm Faulty clutch plate (Chapter 8).mm Fork and bearing not assembled properly (Chapter 8).mm Faulty pressure plate (Chapter 8).mm Pressure plate-to-flywheel bolts loose (Chapter 8).

Clutch slips (engine speed increases with noincrease in vehicle speed)mm Clutch plate worn (Chapter 8).mm Clutch plate is oil-soaked by leaking rear main seal (Chapter 8).mm Warped pressure plate or flywheel (Chapter 8).mm Weak diaphragm spring (Chapter 8).mm Clutch plate overheated.

Grabbing (chattering) as clutch is engagedmm Oil on clutch plate lining, burned or glazed facings (Chapter 8).mm Worn or loose engine or transmission mountings (Chapters 2

and 7A).mm Worn splines on clutch plate hub (Chapter 8).mm Warped pressure plate or flywheel (Chapter 8).

Noise in clutch areamm Fork improperly fitted (Chapter 8).mm Faulty release bearing (Chapter 8).

Clutch pedal stays on floormm Fork binding in housing (Chapter 8).mm Broken release bearing or fork (Chapter 8).

High pedal effortmm Fork binding in housing (Chapter 8).mm Pressure plate faulty (Chapter 8).mm Incorrect-size master or slave cylinder fitted (Chapter 8).

REF•13

REF

Fault Finding

Automatic transmissionNote: Due to the complexity of the automatic transmission, it isdifficult for the home mechanic to properly diagnose and service thisunit. For problems other than the following, the vehicle should betaken to a dealer or transmission specialist.

Fluid leakagemm Automatic transmission fluid is a deep red colour. Fluid leaks

should not be confused with engine oil, which can easily be blownby airflow onto the transmission.

mm To pinpoint a leak, first remove all built-up dirt and grime from thetransmission housing with degreasing agents and/or by steam-cleaning. Then drive the vehicle at low speed, so airflow will notblow the leak far from its source. Raise the vehicle and determinewhere the leak is coming from. Common areas of leakage are:a) Transmission sump (Chapters 1 and 7B)b) Filler pipe (Chapter 7B)c) Transmission fluid cooler lines (Chapter 7B)d) Speedometer sensor (Chapter 7B)

Transmission fluid brown, or has a burned smellmm Transmission fluid burned; fluid should be changed. May indicate

transmission internal fault (Chapters 1 and 7B).

Transmission will not kickdown with acceleratorpedal pressed to the floormm Kickdown cable out of adjustment (Chapter 7B).

General shift mechanism problemsmm Chapter 7B deals with checking and adjusting the shift linkage on

automatic transmissions. Common problems which may beattributed to poorly-adjusted linkage are:a) Engine starting in gears other than Park or Neutral.b) Indicator on selector lever pointing to a gear other than the one

actually being used.c) Vehicle moves when in Park.

mm Refer to Chapter 7B for the shift linkage adjustment procedure.

Engine will start in gears other than Park or Neutralmm Inhibitor switch malfunctioning (Chapter 7B).

Transmission slips, shifts roughly, is noisy, or hasno drive in forward or reverse gearsmm There are many probable causes for the above problems, but the

home mechanic should be concerned with only one possibility -fluid level. Before taking the vehicle to an automatic transmissionspecialist, check the level and condition of the fluid as described inChapter 1. Correct the fluid level as necessary, or change the fluidif needed. If the problem persists, have a professional diagnose theprobable cause.

Manual transmissionVibrationmm Damaged propeller shaft (Chapter 8).mm Out-of-round tyres (Chapter 1).mm Tyre out-of-balance (Chapters 1 and 10).mm Worn propeller shaft universal joint (Chapter 8).

Noisy in neutral with engine runningmm Worn clutch release bearing (Chapter 8).mm Worn transmission input shaft bearing (Chapter 7A).

Noisy in one particular gearmm Damaged or worn constant-mesh gears.mm Damaged or worn synchronisers.

Noisy in all gearsmm Insufficient lubricant (Chapter 1).mm Damaged or worn bearings.mm Worn or damaged input gear shaft and/or output gear shaft.

Slips out of gearmm Worn or incorrectly-adjusted linkage (Chapter 7A).mm Transmission-to-engine mounting bolts loose (Chapter 7A).mm Shift linkage binding (Chapter 7A).mm Worn shift fork (Chapter 7A).

Leaks lubricantmm Excessive amount of lubricant in transmission (Chapters 1 and 7A).mm Loose or broken input shaft bearing retainer (Chapter 7A).mm Input shaft bearing retainer O-ring and/or lip seal damaged

(Chapter 7A).


BrakesNote: Before assuming that a brake problem exists, make sure that:a) The tyres are in good condition and properly inflated (Chapter 1).b) The wheel alignment (tracking) is correct (Chapter 10).c) The vehicle is not loaded with weight in an unequal manner.

Vehicle pulls to one side during brakingmm Incorrect tyre pressures (Chapter 1).mm Wheel alignment (tracking) incorrect (Chapter 10)mm Unmatched tyres on same axle.mm Restricted brake lines or hoses (Chapter 9).mm Malfunctioning caliper assembly (Chapter 9).mm Loose suspension parts (Chapter 10).mm Loose calipers (Chapter 9).

Noise (high-pitched squeal) when the brakes areappliedmm Front and/or rear disc brake pads worn out. The noise comes from

the wear sensor rubbing against the disc. Renew the padsimmediately (Chapter 9).

Brake vibration (pedal pulsates)Note: If the vehicle has ABS, it is normal for the brake pedal to pulsate

when the system is working.mm Excessive lateral disc run-out (Chapter 9).mm Parallelism not within specifications (Chapter 9).mm Uneven pad wear - caused by caliper not sliding, due to improper

clearance or dirt (Chapter 9).mm Defective disc (Chapter 9).

Excessive brake pedal travelmm Partial brake system failure (Chapter 9).mm Insufficient fluid in master cylinder (Chapters 1 and 9).mm Air trapped in system (Chapters 1 and 9).

Excessive pedal effort required to stop vehiclemm Malfunctioning brake servo unit (Chapter 9).mm Partial system failure (Chapter 9).mm Excessively-worn pads or shoes (Chapter 9).mm Caliper piston stuck or sluggish (Chapter 9).mm Brake pads contaminated with oil or grease (Chapter 9).mm New pads fitted and not yet seated. It will take a while for the new

material to seat against the disc.

Dragging brakesmm Master cylinder pistons not returning correctly (Chapter 9).mm Restricted brakes lines or hoses (Chapters 1 and 9).mm Incorrect handbrake adjustment (Chapter 9).mm Rear drum brake self-adjuster mechanism faulty (when applicable)

(Chapter 9).

Grabbing or uneven braking actionmm Malfunction of brake servo unit (Chapter 9).mm Binding brake pedal mechanism (Chapter 9).

Brake pedal feels “spongy” when depressedmm Air in hydraulic lines (Chapter 9).mm Master cylinder mounting bolts loose (Chapter 9).mm Master cylinder defective (Chapter 9).

Brake pedal travels to the floor with little resistancemm Little or no fluid in the master cylinder reservoir, caused by leaking

caliper piston(s), loose, damaged or disconnected brake lines(Chapter 9).

Handbrake does not holdmm Handbrake linkage incorrectly adjusted (Chapter 9).mm Handbrake shoe linings worn out or contaminated (Chapter 9).

REF•15

REF

Fault Finding

Suspension and steeringNote: Before assuming that a problem exists, check the following

items:a) Tyre pressures and tyre condition (also check for out-of-round or

out-of-balance tyres, and bent wheel rims).b) Steering universal joints from the column to the steering gear (for

play or wear).c) Front and rear suspension, and the rack-and-pinion assembly (for

loose or damaged parts).d) Wheel bearings (wheel wobble or roughness when spun).

Vehicle pulls to one sidemm Mismatched or uneven tyres (Chapter 10).mm Broken or sagging springs (Chapter 10).mm Front wheel or rear wheel alignment incorrect (Chapter 10).mm Front brake problem (Chapter 9).

Abnormal or excessive tyre wearmm Front wheel or rear wheel alignment incorrect (Chapter 10).mm Sagging or broken springs (Chapter 10).mm Tyre out of balance (Chapter 10).mm Worn shock absorber (Chapter 10).mm Overloaded vehicle or unsympathetic driving style.mm Tyres not rotated regularly.

Wheel makes a “thumping” noisemm Blister or bump on tyre (Chapter 10).mm Faulty shock absorber action (Chapter 10).mm Wheel bolts loose.

Shimmy, shake or vibrationmm Tyre or wheel out of balance or out of round (Chapter 10).mm Loose, worn or incorrectly-adjusted wheel bearings (Chapter 1).mm Worn tie-rod ends (Chapter 10).mm Worn balljoints (Chapter 10).mm Excessive wheel run-out (Chapter 10).mm Blister or bump on tyre (Chapter 10).mm Wheel bolts loose.

High steering effortmm Lack of lubrication at balljoints, tie-rod ends and steering gear

(Chapter 1).mm Incorrect front wheel alignment (Chapter 10).mm Low tyre pressure(s) (Chapter 1).mm Power steering fluid low, or steering pump drivebelt slipping,

where applicable (Chapter 10)

Poor steering self-centringmm Lack of lubrication at balljoints and tie-rod ends (Chapter 1).mm Binding in balljoints (Chapter 10).mm Binding in steering column (Chapter 10).mm Lack of lubricant in steering gear (Chapter 10).mm Inaccurate front wheel alignment (Chapter 10).

Abnormal noise at the front endmm Lack of lubrication at balljoints and tie-rod ends (Chapter 1).mm Damaged shock absorber mounting (Chapter 10).mm Worn control arm bushings or tie-rod ends (Chapter 10).mm Loose anti-roll bar (Chapter 10).mm Loose wheel bolts.mm Loose suspension mounting bolts (Chapter 10).

Wandering or poor steering stabilitymm Mismatched or uneven tyres (Chapter 10).mm Lack of lubrication at balljoints and tie-rod ends (Chapter 1).mm Worn shock absorbers (Chapter 10).mm Loose anti-roll bar (Chapter 10).mm Broken or sagging springs (Chapter 10).mm Front or rear wheel alignment incorrect (Chapter 10).

Erratic steering when brakingmm Wheel bearings worn (Chapter 1).mm Broken or sagging springs (Chapter 10).mm Leaking wheel cylinder (rear drum brake models) or caliper

(Chapter 9).mm Warped discs (Chapter 9).

Excessive pitching and/or rolling around corners orduring brakingmm Loose anti-roll bar (Chapter 10).mm Worn shock absorbers or mountings (Chapter 10).mm Broken or sagging springs (Chapter 10).mm Overloaded vehicle.

Suspension bottomsmm Overloaded vehicle.mm Worn shock absorbers (Chapter 10).mm Broken or sagging springs, or incorrect springs fitted (Chapter 10).

Unevenly-worn tyresmm Front wheel or rear wheel alignment incorrect (Chapter 10).mm Worn shock absorbers (Chapter 10).mm Wheel bearings worn (Chapter 10).mm Excessive tyre or wheel run-out (Chapter 10).mm Worn balljoints (Chapter 10).

Excessive tyre wear on outside edgemm Tyre pressures incorrect (Chapter 1).mm Excessive cornering speed.mm Wheel alignment incorrect (excessive toe-in) (Chapter 10).mm Suspension components damaged (Chapter 10).

Excessive tyre wear on inside edgemm Tyre pressures incorrect (Chapter 1).mm Wheel alignment incorrect (excessive toe-out) (Chapter 10).mm Loose or damaged steering components (Chapter 10).

Tyre tread worn in one placemm Tyres out of balance.mm Damaged or buckled wheel. Inspect and renew if necessary.mm Defective tyre (Chapter 1).

Excessive play or looseness in steering systemmm Wheel bearing(s) worn (Chapter 10.mm Tie-rod end loose or worn (Chapter 10).mm Steering gear mountings loose (Chapter 10).

Rattling or clicking noise in steering gearmm Insufficient or incorrect lubricant in rack-and-pinion assembly

(Chapter 10).mm Steering gear mountings loose (Chapter 10).

REF•17

REF

Conversion Factors

Length (distance)Inches (in) 25.4 = Millimetres (mm) x 0.0394 = Inches (in)Feet (ft) 0.305 = Metres (m) x 3.281 = Feet (ft)Miles 1.609 = Kilometres (km) x 0.621 = Miles

Volume (capacity)Cubic inches (cu in; in3) x 16.387 = Cubic centimetres (cc; cm3) x 0.061 = Cubic inches (cu in; in3)Imperial pints (Imp pt) x 0.568 = Litres (l) x 1.76 = Imperial pints (Imp pt)Imperial quarts (Imp qt) x 1.137 = Litres (l) x 0.88 = Imperial quarts (Imp qt)Imperial quarts (Imp qt) x 1.201 = US quarts (US qt) x 0.833 = Imperial quarts (Imp qt)US quarts (US qt) x 0.946 = Litres (l) x 1.057 = US quarts (US qt)Imperial gallons (Imp gal) x 4.546 = Litres (l) x 0.22 = Imperial gallons (Imp gal)Imperial gallons (Imp gal) x 1.201 = US gallons (US gal) x 0.833 = Imperial gallons (Imp gal)US gallons (US gal) x 3.785 = Litres (l) x 0.264 = US gallons (US gal)

Mass (weight)Ounces (oz) x 28.35 = Grams (g) x 0.035 = Ounces (oz)Pounds (lb) x 0.454 = Kilograms (kg) x 2.205 = Pounds (lb)

ForceOunces-force (ozf; oz) x 0.278 = Newtons (N) x 3.6 = Ounces-force (ozf; oz)Pounds-force (lbf; lb) x 4.448 = Newtons (N) x 0.225 = Pounds-force (lbf; lb)Newtons (N) x 0.1 = Kilograms-force (kgf; kg) x 9.81 = Newtons (N)

PressurePounds-force per square inch x 0.070 = Kilograms-force per square x 14.223 = Pounds-force per square inch(psi; lbf/in2; lb/in2) centimetre (kgf/cm2; kg/cm2) (psi; lbf/in2; lb/in2)Pounds-force per square inch x 0.068 = Atmospheres (atm) x 14.696 = Pounds-force per square inch(psi; lbf/in2; lb/in2) (psi; lbf/in2; lb/in2)Pounds-force per square inch x 0.069 = Bars x 14.5 = Pounds-force per square inch(psi; lbf/in2; lb/in2) (psi; lbf/in2; lb/in2)Pounds-force per square inch x 6.895 = Kilopascals (kPa) x 0.145 = Pounds-force per square inch(psi; lbf/in2; lb/in2) (psi; lbf/in2; lb/in2)Kilopascals (kPa) x 0.01 = Kilograms-force per square x 98.1 = Kilopascals (kPa)

centimetre (kgf/cm2; kg/cm2)Millibar (mbar) x 100 = Pascals (Pa) x 0.01 = Millibar (mbar)Millibar (mbar) x 0.0145 = Pounds-force per square inch x 68.947 = Millibar (mbar)

(psi; lbf/in2; lb/in2)Millibar (mbar) x 0.75 = Millimetres of mercury (mmHg) x 1.333 = Millibar (mbar)Millibar (mbar) x 0.401 = Inches of water (inH2O) x 2.491 = Millibar (mbar)Millimetres of mercury (mmHg) x 0.535 = Inches of water (inH2O) x 1.868 = Millimetres of mercury (mmHg)Inches of water (inH2O) x 0.036 = Pounds-force per square inch x 27.68 = Inches of water (inH2O)

(psi; lbf/in2; lb/in2)

Torque (moment of force)Pounds-force inches (lbf in; lb in) x 1.152 = Kilograms-force centimetre x 0.868 = Pounds-force inches (lbf in; lb in)

(kgf cm; kg cm)Pounds-force inches (lbf in; lb in) x 0.113 = Newton metres (Nm) x 8.85 = Pounds-force inches (lbf in; lb in)Pounds-force inches (lbf in; lb in) x 0.083 = Pounds-force feet (lbf ft; lb ft) x 12 = Pounds-force inches (lbf in; lb in)Pounds-force feet (lbf ft; lb ft) x 0.138 = Kilograms-force metres (kgf m; kg m) x 7.233 = Pounds-force feet (lbf ft; lb ft)Pounds-force feet (lbf ft; lb ft) x 1.356 = Newton metres (Nm) x 0.738 = Pounds-force feet (lbf ft; lb ft)Newton metres (Nm) x 0.102 = Kilograms-force metres (kgf m; kg m) x 9.804 = Newton metres (Nm)

PowerHorsepower (hp) x 745.7 = Watts (W) x 0.0013 = Horsepower (hp)

Velocity (speed)Miles per hour (miles/hr; mph) x 1.609 = Kilometres per hour (km/hr; kph) x 0.621 = Miles per hour (miles/hr; mph)

Fuel consumption*Miles per gallon (mpg) x 0.354 = Kilometres per litre (km/l) x 2.825 = Miles per gallon (mpg)

* It is common practice to convert from miles per gallon (mpg) to litres/100 kilometres (l/100km), where mpg x l/100 km = 282

TemperatureDegrees Fahrenheit = (°C x 1.8) + 32 Degrees Celsius (Degrees Centigrade; °C) = (°F - 32) x 0.56

REF•18 Automotive chemicals and lubricantsA number of automotive chemicals and

lubricants are available for use during vehiclemaintenance and repair. They include a widevariety of products ranging from cleaningsolvents and degreasers to lubricants andprotective sprays for rubber, plastic and vinyl.

CleanersCarburettor cleaner and choke cleaner

is a strong solvent for gum, varnish andcarbon. Most carburettor cleaners leave adry-type lubricant film which will not harden orgum up. Because of this film, it is notrecommended for use on electricalcomponents.

Brake system cleaner is used to removegrease and brake fluid from the brake system,where clean surfaces are absolutelynecessary. It leaves no residue, and ofteneliminates brake squeal caused bycontaminants.

Electrical cleaner removes oxidation,corrosion and carbon deposits from electricalcontacts, restoring full current flow. It can alsobe used to clean spark plugs, carburettor jets,voltage regulators and other parts where anoil-free surface is desired.

Moisture dispersants remove water andmoisture from electrical components such asalternators, voltage regulators, electricalconnectors and fuse blocks. They are non-conductive and non-corrosive.

Degreasers are heavy-duty solvents usedto remove grease from the outside of theengine and from chassis components. Theycan be sprayed or brushed on, and are usuallyrinsed off with water.

LubricantsEngine oil is the lubricant formulated for

use in engines. It normally contains a widevariety of additives to prevent corrosion andreduce foaming and wear. Engine oil comes invarious weights (viscosity ratings) from 5 to60. The recommended weight of the oildepends on the season, temperature and thedemands on the engine. Light oil is used incold climates and under light load conditions.Heavy oil is used in hot climates, and wherehigh loads are encountered. Multi-viscosity(multigrade) oils are designed to havecharacteristics of both light and heavy oils,and are available in a number of weights from5W-20 to 20W-50.

Gear oil is designed to be used indifferentials, manual transmissions and otherareas where high-temperature lubrication isrequired.

Chassis and wheel bearing grease is aheavy grease used where increased loads andfriction are encountered, such as for wheelbearings, balljoints, tie-rod ends and universaljoints.

High-temperature wheel bearing greaseis designed to withstand the extremetemperatures encountered by wheel bearingsin disc brake-equipped vehicles. It usuallycontains molybdenum disulphide (moly),which is a dry-type lubricant.

White grease is a heavy grease for metal-to-metal applications where water is aproblem. White grease stays soft at both lowand high temperatures, and will not wash offor dilute in the presence of water.

Assembly lube is a special extreme-pressure lubricant, usually containing moly,used to lubricate high-load parts (such asmain and rod bearings and cam lobes) forinitial start-up of a new engine. The assemblylube lubricates the parts without beingsqueezed out or washed away until the engineoiling system begins to function.

Silicone lubricants are used to protectrubber, plastic, vinyl and nylon parts.

Graphite lubricants are used where oilscannot be used due to contaminationproblems, such as in locks. The dry graphitewill lubricate metal parts while remaininguncontaminated by dirt, water, oil or acids. Itis electrically conductive, and will not foulelectrical contacts in locks such as theignition switch.

Penetrating oils loosen and lubricatefrozen, rusted and corroded fasteners andprevent future rusting or freezing.

Heat-sink grease is a special electricallynon-conductive grease that is used formounting electronic ignition modules where itis essential that heat is transferred away fromthe module.

SealantsRTV sealant is one of the most widely-

used gasket compounds. Made from silicone,RTV is air-curing; it seals, bonds, waterproofs,fills surface irregularities, remains flexible,doesn’t shrink, is relatively easy to remove,and is used as a supplementary sealer withalmost all low- and medium-temperaturegaskets.

Anaerobic sealant is much like RTV in thatit can be used either to seal gaskets or to formgaskets by itself. It remains flexible, is solvent-resistant, and fills surface imperfections. Thedifference between an anaerobic sealant andan RTV-type sealant is in the curing. RTVcures when exposed to air, while an anaerobicsealant cures only in the absence of air. Thismeans that an anaerobic sealant cures onlyafter the assembly of parts, sealing themtogether.

Thread and pipe sealant is used forsealing hydraulic and pneumatic fittings andvacuum lines. It is usually made from a Tefloncompound, and comes in a spray, a paint-onliquid and as a wrap-around tape.

ChemicalsAnti-seize compound prevents seizing,

chafing, cold welding, rust and corrosion infasteners. High-temperature anti-seize,usually made with copper and graphitelubricants, is used for exhaust system andexhaust manifold bolts.

Anaerobic locking compounds are usedto keep fasteners from vibrating or workingloose, and cure only after installation, in theabsence of air. Medium-strength lockingcompound is used for small nuts, bolts andscrews that may be removed later. High-strength locking compound is for large nuts,bolts and studs which aren’t removed on aregular basis.

Oil additives range from viscosity indeximprovers to chemical treatments that claimto reduce internal engine friction. It should benoted that most oil manufacturers cautionagainst using additives with their oils.

Fuel additives perform several functions,depending on their chemical make-up. Theyusually contain solvents that help dissolvegum and varnish that build up on carburettor,fuel injection and intake parts. They also serveto break down carbon deposits that form onthe inside surfaces of the combustionchambers. Some additives contain uppercylinder lubricants for valves and piston rings,and others contain chemicals to removecondensation from the fuel tank.

MiscellaneousBrake fluid is specially-formulated

hydraulic fluid that can withstand the heat andpressure encountered in brake systems. It ispoisonous and inflammable. Care must betaken so this fluid does not come in contactwith painted surfaces or plastics. An openedcontainer should always be resealed, toprevent contamination by water or dirt. Brakefluid absorbs moisture from the air, if left in anunsealed container.

Weatherstrip adhesive is used to bondweatherstripping around doors, windows andboot lids. It is sometimes used to attach trimpieces.

Underseal is a petroleum-based, tar-likesubstance that is designed to protect metalsurfaces on the underside of the vehicle fromcorrosion. It also acts as a sound-deadeningagent by insulating the bottom of the vehicle.

Waxes and polishes are used to helpprotect painted and plated surfaces from theweather. Different types of paint may requirethe use of different types of wax and polish.Some polishes utilise a chemical or abrasivecleaner to help remove the top layer ofoxidised (dull) paint on older vehicles. Inrecent years, many non-wax polishescontaining a wide variety of chemicals such aspolymers and silicones have been introduced.These non-wax polishes are usually easier toapply, and last longer than conventionalwaxes and polishes.

REF•19

REF

Buying spare parts & vehicle identification numbers

Buying spare partsSpare parts are available from many

sources; for example, BMW garages, othergarages and accessory shops, and motorfactors. Our advice regarding spare partsources is as follows.

Officially-appointed BMW garages - This isthe best source for parts which are peculiar toyour vehicle, and which are not generallyavailable (eg complete cylinder heads, internaltransmission components, badges, interiortrim etc). It is also the only place at which youshould buy parts if the vehicle is still underwarranty. To be sure of obtaining the correctparts, it will be necessary to give the storemanthe full Vehicle Identification Number, and ifpossible, to take the old parts along forpositive identification. Many parts areavailable under a factory exchange scheme -any parts returned should always be clean. Itobviously makes good sense to go straight tothe specialists on your vehicle for this type ofpart, as they are best equipped to supply you.

Other garages and accessory shops - Theseare often very good places to buy materialsand components needed for the maintenanceof your vehicle (eg oil filters, spark plugs,bulbs, drivebelts, oils and greases, touch-uppaint, filler paste, etc). They also sell generalaccessories, usually have convenient openinghours, charge lower prices, and can often befound not far from home.

Motor factors - Good factors will stock allthe more important components which wear

out comparatively quickly (eg exhaustsystems, brake pads, seals and hydraulicparts, clutch components, bearing shells,pistons, valves etc). Motor factors will oftenprovide new or reconditioned components ona part-exchange basis - this can save aconsiderable amount of money.

Vehicle identificationnumbers

Modifications are a continuing andunpublicised process in vehicle manufacture,quite apart from major model changes. Spareparts manuals and lists are compiled upon anumerical basis, the appropriate identificationnumber or code being essential to correctidentification of the component concerned.

When ordering spare parts, always give asmuch information as possible. Quote thevehicle model, year of manufacture, VehicleIdentification Number and engine numbers, asappropriate.

The Vehicle Identification Number (VIN) islocated on the right-hand front wheel archnext to the front suspension strut uppermounting, on the driver’s door, and on a plateon top of the facia, just inside the windscreen(see illustrations).

The engine number is stamped on amachined face on the left-hand side of thecylinder block, near the base of the oil leveldipstick tube.

The body number is located on the seambetween the left-hand front wing and innerpanel.

The VIN (arrowed) is stamped on thebulkhead

The VIN is also present on the edge of thedriver’s door

REF•20 Glossary of Technical Terms

AABS (Anti-lock brake system) A system,usually electronically controlled, that sensesincipient wheel lockup during braking andrelieves hydraulic pressure at wheels that areabout to skid.Air bag An inflatable bag hidden in thesteering wheel (driver’s side) or the dash orglovebox (passenger side). In a head-oncollision, the bags inflate, preventing thedriver and front passenger from being thrownforward into the steering wheel or windscreen.Air cleaner A metal or plastic housing,containing a filter element, which removesdust and dirt from the air being drawn into theengine.Air filter element The actual filter in an aircleaner system, usually manufactured frompleated paper and requiring renewal at regularintervals.

Allen key A hexagonal wrench which fits intoa recessed hexagonal hole.Alligator clip A long-nosed spring-loadedmetal clip with meshing teeth. Used to maketemporary electrical connections.Alternator A component in the electricalsystem which converts mechanical energyfrom a drivebelt into electrical energy tocharge the battery and to operate the startingsystem, ignition system and electricalaccessories.

Ampere (amp) A unit of measurement for theflow of electric current. One amp is theamount of current produced by one voltacting through a resistance of one ohm.Anaerobic sealer A substance used toprevent bolts and screws from loosening.Anaerobic means that it does not requireoxygen for activation. The Loctite brand iswidely used.Antifreeze A substance (usually ethyleneglycol) mixed with water, and added to avehicle’s cooling system, to prevent freezingof the coolant in winter. Antifreeze alsocontains chemicals to inhibit corrosion andthe formation of rust and other deposits that

would tend to clog the radiator and coolantpassages and reduce cooling efficiency.Anti-seize compound A coating thatreduces the risk of seizing on fasteners thatare subjected to high temperatures, such asexhaust manifold bolts and nuts.

Asbestos A natural fibrous mineral with greatheat resistance, commonly used in thecomposition of brake friction materials.Asbestos is a health hazard and the dustcreated by brake systems should never beinhaled or ingested.Axle A shaft on which a wheel revolves, orwhich revolves with a wheel. Also, a solidbeam that connects the two wheels at oneend of the vehicle. An axle which alsotransmits power to the wheels is known as alive axle.

Axleshaft A single rotating shaft, on eitherside of the differential, which delivers powerfrom the final drive assembly to the drivewheels. Also called a driveshaft or a halfshaft.

BBall bearing An anti-friction bearingconsisting of a hardened inner and outer racewith hardened steel balls between two races.

Bearing The curved surface on a shaft or in abore, or the part assembled into either, thatpermits relative motion between them withminimum wear and friction.Big-end bearing The bearing in the end ofthe connecting rod that’s attached to thecrankshaft.Bleed nipple A valve on a brake wheelcylinder, caliper or other hydraulic componentthat is opened to purge the hydraulic systemof air. Also called a bleed screw.

Brake bleeding Procedure for removing airfrom lines of a hydraulic brake system.Brake disc The component of a disc brakethat rotates with the wheels.Brake drum The component of a drum brakethat rotates with the wheels.Brake linings The friction material whichcontacts the brake disc or drum to retard thevehicle’s speed. The linings are bonded orriveted to the brake pads or shoes.Brake pads The replaceable friction padsthat pinch the brake disc when the brakes areapplied. Brake pads consist of a frictionmaterial bonded or riveted to a rigid backingplate.Brake shoe The crescent-shaped carrier towhich the brake linings are mounted andwhich forces the lining against the rotatingdrum during braking.Braking systems For more information onbraking systems, consult the HaynesAutomotive Brake Manual.Breaker bar A long socket wrench handleproviding greater leverage.Bulkhead The insulated partition betweenthe engine and the passenger compartment.

CCaliper The non-rotating part of a disc-brakeassembly that straddles the disc and carriesthe brake pads. The caliper also contains thehydraulic components that cause the pads topinch the disc when the brakes are applied. Acaliper is also a measuring tool that can be setto measure inside or outside dimensions of anobject.

Brake bleeding

Bearing

Axle assembly

Anti-seize compound

Alternator (exploded view)

Air filter

REF•21

REF

Glossary of Technical TermsCamshaft A rotating shaft on which a seriesof cam lobes operate the valve mechanisms.The camshaft may be driven by gears, bysprockets and chain or by sprockets and abelt.Canister A container in an evaporativeemission control system; contains activatedcharcoal granules to trap vapours from thefuel system.

Carburettor A device which mixes fuel withair in the proper proportions to provide adesired power output from a spark ignitioninternal combustion engine.

Castellated Resembling the parapets alongthe top of a castle wall. For example, acastellated balljoint stud nut.

Castor In wheel alignment, the backward orforward tilt of the steering axis. Castor ispositive when the steering axis is inclinedrearward at the top.

Catalytic converter A silencer-like device inthe exhaust system which converts certainpollutants in the exhaust gases into lessharmful substances.

Circlip A ring-shaped clip used to preventendwise movement of cylindrical parts andshafts. An internal circlip is installed in agroove in a housing; an external circlip fits intoa groove on the outside of a cylindrical piecesuch as a shaft.Clearance The amount of space betweentwo parts. For example, between a piston anda cylinder, between a bearing and a journal,etc.Coil spring A spiral of elastic steel found invarious sizes throughout a vehicle, forexample as a springing medium in thesuspension and in the valve train.Compression Reduction in volume, andincrease in pressure and temperature, of agas, caused by squeezing it into a smallerspace.Compression ratio The relationship betweencylinder volume when the piston is at topdead centre and cylinder volume when thepiston is at bottom dead centre.Constant velocity (CV) joint A type ofuniversal joint that cancels out vibrationscaused by driving power being transmittedthrough an angle.Core plug A disc or cup-shaped metal deviceinserted in a hole in a casting through whichcore was removed when the casting wasformed. Also known as a freeze plug orexpansion plug. Crankcase The lower part of the engineblock in which the crankshaft rotates.Crankshaft The main rotating member, orshaft, running the length of the crankcase,with offset “throws” to which the connectingrods are attached.

Crocodile clip See Alligator clip

DDiagnostic code Code numbers obtained byaccessing the diagnostic mode of an enginemanagement computer. This code can beused to determine the area in the systemwhere a malfunction may be located.Disc brake A brake design incorporating arotating disc onto which brake pads aresqueezed. The resulting friction converts theenergy of a moving vehicle into heat.Double-overhead cam (DOHC) An enginethat uses two overhead camshafts, usuallyone for the intake valves and one for theexhaust valves.Drivebelt(s) The belt(s) used to driveaccessories such as the alternator, waterpump, power steering pump, air conditioningcompressor, etc. off the crankshaft pulley.

Driveshaft Any shaft used to transmitmotion. Commonly used when referring to theaxleshafts on a front wheel drive vehicle.

Drum brake A type of brake using a drum-shaped metal cylinder attached to the innersurface of the wheel. When the brake pedal ispressed, curved brake shoes with frictionlinings press against the inside of the drum toslow or stop the vehicle.

Castellated nut

Catalytic converter

Crankshaft assembly

Carburettor

Canister

Drum brake assembly

Accessory drivebelts

Driveshaft

REF•22 Glossary of Technical Terms

EEGR valve A valve used to introduce exhaustgases into the intake air stream.

Electronic control unit (ECU) A computerwhich controls (for instance) ignition and fuelinjection systems, or an anti-lock brakingsystem. For more information refer to theHaynes Automotive Electrical and ElectronicSystems Manual.Electronic Fuel Injection (EFI) A computercontrolled fuel system that distributes fuelthrough an injector located in each intake portof the engine.Emergency brake A braking system,independent of the main hydraulic system,that can be used to slow or stop the vehicle ifthe primary brakes fail, or to hold the vehiclestationary even though the brake pedal isn’tdepressed. It usually consists of a hand leverthat actuates either front or rear brakesmechanically through a series of cables andlinkages. Also known as a handbrake orparking brake.Endfloat The amount of lengthwisemovement between two parts. As applied to acrankshaft, the distance that the crankshaftcan move forward and back in the cylinderblock.Engine management system (EMS) Acomputer controlled system which managesthe fuel injection and the ignition systems inan integrated fashion.Exhaust manifold A part with severalpassages through which exhaust gases leavethe engine combustion chambers and enterthe exhaust pipe.

FFan clutch A viscous (fluid) drive couplingdevice which permits variable engine fanspeeds in relation to engine speeds.

Feeler blade A thin strip or blade of hardenedsteel, ground to an exact thickness, used tocheck or measure clearances between parts.

Firing order The order in which the enginecylinders fire, or deliver their power strokes,beginning with the number one cylinder.Flywheel A heavy spinning wheel in whichenergy is absorbed and stored by means ofmomentum. On cars, the flywheel is attachedto the crankshaft to smooth out firingimpulses.Free play The amount of travel before anyaction takes place. The “looseness” in alinkage, or an assembly of parts, between theinitial application of force and actualmovement. For example, the distance thebrake pedal moves before the pistons in themaster cylinder are actuated.Fuse An electrical device which protects acircuit against accidental overload. The typicalfuse contains a soft piece of metal which iscalibrated to melt at a predetermined currentflow (expressed as amps) and break thecircuit.Fusible link A circuit protection deviceconsisting of a conductor surrounded byheat-resistant insulation. The conductor issmaller than the wire it protects, so it acts asthe weakest link in the circuit. Unlike a blownfuse, a failed fusible link must frequently becut from the wire for replacement.

GGap The distance the spark must travel injumping from the centre electrode to the side

electrode in a spark plug. Also refers to thespacing between the points in a contactbreaker assembly in a conventional points-type ignition, or to the distance between thereluctor or rotor and the pickup coil in anelectronic ignition.Gasket Any thin, soft material - usually cork,cardboard, asbestos or soft metal - installedbetween two metal surfaces to ensure a goodseal. For instance, the cylinder head gasketseals the joint between the block and thecylinder head.

Gauge An instrument panel display used tomonitor engine conditions. A gauge with amovable pointer on a dial or a fixed scale is ananalogue gauge. A gauge with a numericalreadout is called a digital gauge.

HHalfshaft A rotating shaft that transmitspower from the final drive unit to a drivewheel, usually when referring to a live rearaxle.Harmonic balancer A device designed toreduce torsion or twisting vibration in thecrankshaft. May be incorporated in thecrankshaft pulley. Also known as a vibrationdamper.Hone An abrasive tool for correcting smallirregularities or differences in diameter in anengine cylinder, brake cylinder, etc.Hydraulic tappet A tappet that utiliseshydraulic pressure from the engine’slubrication system to maintain zero clearance(constant contact with both camshaft andvalve stem). Automatically adjusts to variationin valve stem length. Hydraulic tappets alsoreduce valve noise.

IIgnition timing The moment at which thespark plug fires, usually expressed in thenumber of crankshaft degrees before thepiston reaches the top of its stroke.Inlet manifold A tube or housing withpassages through which flows the air-fuelmixture (carburettor vehicles and vehicles withthrottle body injection) or air only (port fuel-injected vehicles) to the port openings in thecylinder head.

Exhaust manifold

Feeler blade

Adjusting spark plug gap

Gasket

EGR valve

REF•23

REF

Glossary of Technical Terms

JJump start Starting the engine of a vehiclewith a discharged or weak battery byattaching jump leads from the weak battery toa charged or helper battery.

LLoad Sensing Proportioning Valve (LSPV) Abrake hydraulic system control valve thatworks like a proportioning valve, but alsotakes into consideration the amount of weightcarried by the rear axle.Locknut A nut used to lock an adjustmentnut, or other threaded component, in place.For example, a locknut is employed to keepthe adjusting nut on the rocker arm inposition.Lockwasher A form of washer designed toprevent an attaching nut from working loose.

MMacPherson strut A type of frontsuspension system devised by EarleMacPherson at Ford of England. In its originalform, a simple lateral link with the anti-roll barcreates the lower control arm. A long strut - anintegral coil spring and shock absorber - ismounted between the body and the steeringknuckle. Many modern so-called MacPhersonstrut systems use a conventional lower A-armand don’t rely on the anti-roll bar for location.Multimeter An electrical test instrument withthe capability to measure voltage, current andresistance.

NNOx Oxides of Nitrogen. A common toxicpollutant emitted by petrol and diesel enginesat higher temperatures.

OOhm The unit of electrical resistance. Onevolt applied to a resistance of one ohm willproduce a current of one amp.Ohmmeter An instrument for measuringelectrical resistance.O-ring A type of sealing ring made of aspecial rubber-like material; in use, the O-ringis compressed into a groove to provide thesealing action.

Overhead cam (ohc) engine An engine withthe camshaft(s) located on top of the cylinderhead(s).Overhead valve (ohv) engine An engine withthe valves located in the cylinder head, butwith the camshaft located in the engine block.Oxygen sensor A device installed in theengine exhaust manifold, which senses theoxygen content in the exhaust and convertsthis information into an electric current. Alsocalled a Lambda sensor.

PPhillips screw A type of screw head having across instead of a slot for a correspondingtype of screwdriver.Plastigage A thin strip of plastic thread,available in different sizes, used for measuringclearances. For example, a strip of Plastigageis laid across a bearing journal. The parts areassembled and dismantled; the width of thecrushed strip indicates the clearance betweenjournal and bearing.

Propeller shaft The long hollow tube withuniversal joints at both ends that carriespower from the transmission to the differentialon front-engined rear wheel drive vehicles.Proportioning valve A hydraulic controlvalve which limits the amount of pressure tothe rear brakes during panic stops to preventwheel lock-up.

RRack-and-pinion steering A steering systemwith a pinion gear on the end of the steeringshaft that mates with a rack (think of a gearedwheel opened up and laid flat). When thesteering wheel is turned, the pinion turns,moving the rack to the left or right. Thismovement is transmitted through the trackrods to the steering arms at the wheels.Radiator A liquid-to-air heat transfer devicedesigned to reduce the temperature of thecoolant in an internal combustion enginecooling system. Refrigerant Any substance used as a heattransfer agent in an air-conditioning system.R-12 has been the principle refrigerant formany years; recently, however, manufacturershave begun using R-134a, a non-CFCsubstance that is considered less harmful to

the ozone in the upper atmosphere.Rocker arm A lever arm that rocks on a shaftor pivots on a stud. In an overhead valveengine, the rocker arm converts the upwardmovement of the pushrod into a downwardmovement to open a valve.Rotor In a distributor, the rotating deviceinside the cap that connects the centreelectrode and the outer terminals as it turns,distributing the high voltage from the coilsecondary winding to the proper spark plug.Also, that part of an alternator which rotatesinside the stator. Also, the rotating assemblyof a turbocharger, including the compressorwheel, shaft and turbine wheel.Runout The amount of wobble (in-and-outmovement) of a gear or wheel as it’s rotated.The amount a shaft rotates “out-of-true.” Theout-of-round condition of a rotating part.

SSealant A liquid or paste used to preventleakage at a joint. Sometimes used inconjunction with a gasket.Sealed beam lamp An older headlight designwhich integrates the reflector, lens andfilaments into a hermetically-sealed one-pieceunit. When a filament burns out or the lenscracks, the entire unit is simply replaced.Serpentine drivebelt A single, long, wideaccessory drivebelt that’s used on somenewer vehicles to drive all the accessories,instead of a series of smaller, shorter belts.Serpentine drivebelts are usually tensioned byan automatic tensioner.

Shim Thin spacer, commonly used to adjustthe clearance or relative positions betweentwo parts. For example, shims inserted into orunder bucket tappets control valveclearances. Clearance is adjusted bychanging the thickness of the shim.Slide hammer A special puller that screwsinto or hooks onto a component such as ashaft or bearing; a heavy sliding handle on theshaft bottoms against the end of the shaft toknock the component free.Sprocket A tooth or projection on theperiphery of a wheel, shaped to engage with achain or drivebelt. Commonly used to refer tothe sprocket wheel itself.Starter inhibitor switch On vehicles with anO-ring

Serpentine drivebelt

Plastigage

REF•24 Glossary of Technical Termsautomatic transmission, a switch thatprevents starting if the vehicle is not in Neutralor Park.Strut See MacPherson strut.

TTappet A cylindrical component whichtransmits motion from the cam to the valvestem, either directly or via a pushrod androcker arm. Also called a cam follower.Thermostat A heat-controlled valve thatregulates the flow of coolant between thecylinder block and the radiator, so maintainingoptimum engine operating temperature. Athermostat is also used in some air cleaners inwhich the temperature is regulated.Thrust bearing The bearing in the clutchassembly that is moved in to the release leversby clutch pedal action to disengage theclutch. Also referred to as a release bearing.Timing belt A toothed belt which drives thecamshaft. Serious engine damage may resultif it breaks in service.Timing chain A chain which drives thecamshaft.Toe-in The amount the front wheels arecloser together at the front than at the rear. Onrear wheel drive vehicles, a slight amount oftoe-in is usually specified to keep the frontwheels running parallel on the road byoffsetting other forces that tend to spread thewheels apart.Toe-out The amount the front wheels arecloser together at the rear than at the front. On

front wheel drive vehicles, a slight amount oftoe-out is usually specified.Tools For full information on choosing andusing tools, refer to the Haynes AutomotiveTools Manual.Tracer A stripe of a second colour applied toa wire insulator to distinguish that wire fromanother one with the same colour insulator.Tune-up A process of accurate and carefuladjustments and parts replacement to obtainthe best possible engine performance.Turbocharger A centrifugal device, driven byexhaust gases, that pressurises the intake air.Normally used to increase the power outputfrom a given engine displacement, but canalso be used primarily to reduce exhaustemissions (as on VW’s “Umwelt” Dieselengine).

UUniversal joint or U-joint A double-pivotedconnection for transmitting power from adriving to a driven shaft through an angle. A U-joint consists of two Y-shaped yokes and across-shaped member called the spider.

VValve A device through which the flow ofliquid, gas, vacuum, or loose material in bulkmay be started, stopped, or regulated by amovable part that opens, shuts, or partially

obstructs one or more ports or passageways.A valve is also the movable part of such adevice.Valve clearance The clearance between thevalve tip (the end of the valve stem) and therocker arm or tappet. The valve clearance ismeasured when the valve is closed.Vernier caliper A precision measuringinstrument that measures inside and outsidedimensions. Not quite as accurate as amicrometer, but more convenient.Viscosity The thickness of a liquid or itsresistance to flow.Volt A unit for expressing electrical “pressure”in a circuit. One volt that will produce a currentof one ampere through a resistance of oneohm.

WWelding Various processes used to join metalitems by heating the areas to be joined to amolten state and fusing them together. Formore information refer to the HaynesAutomotive Welding Manual.Wiring diagram A drawing portraying thecomponents and wires in a vehicle’s electricalsystem, using standardised symbols. Formore information refer to the HaynesAutomotive Electrical and Electronic SystemsManual.

REF•25

REF

Index

Note: References throughout this index relate to Chapter•page number

AABS - 9•2Accelerator cable - 4•9Acknowledgements - 0•4Aerial - 12•4Air bags - 0•5Air cleaner - 4•8Air conditioning system - 3•2, 3•7, 3•8,

3•9, 3•10Air filter - 1•20Air gap - 5•7Air intake system - 4•2, 4•14Airflow meter - 4•15, 6•4Alternator - 5•10Anti-lock Braking system (ABS) - 9•2Anti-roll bar - 10•4, 10•9Anti-theft audio system - 0•7Antifreeze - 1•3, 1-8, 3•2Asbestos - 0•5ATF - 1•3, 1•13, 1•23Automatic choke - 4•13Automatic transmission - 7B•1 et seqAutomatic transmission fault finding -

7B•4, REF•13Automatic transmission fluid - 1•3, 1•13,

1•23

BBackfire - REF•11Balljoints - 10•7Battery - 0•5, 1•16, 5•2Battery fault - REF•11Big-end bearings - 2B•17, 2B•21Bleeding brakes - 9•14Bleeding clutch - 8•4Bleeding power steering - 10•16

Block - 2B•14, 2B•15Blower motor - 3•7Body corrosion - REF•4Body electrical systems - 12•1 et seqBodywork and fittings - 11•1 et seqBonnet - 11•4Boot lid - 11•6Boots - 8•9, 10•13Brake fluid - 1•3, 1•9Brake lines and hoses - 1•22, 9•13Braking system - 1•22, 9•1 et seq, REF•1,

REF•2, REF•3Braking system fault finding - REF•14Bulbs - 12•6Bumpers - 11•6Burning - 0•5

CCables - 4•9, 5•2, 7B•3, 9•12Calipers - 9•4Cam followers - 2B•11Camshaft - 2A•12, 2B•11Carburettor - 4•10, 4•11Carpets - 11•2Catalytic converter - 4•20, 6•6Central locking - 12•8Charging - 1•17, 5•9Chemicals - REF•18Choke - 4•13Clutch and driveline - 8•1 et seqClutch fault finding - REF•12Clutch fluid - 1•3, 1•9CO level adjustment - 1•15, REF•4Coil - 5•5Coil springs - 10•7, 10•9Cold start injectors - 4•17, 4•18Compression check - 2B•4

Compressor - 3•8Condenser - 3•9Connecting rods - 2B•12, 2B•16, 2B•21Constant velocity (CV) joint - 8•2, 8•8, 8•9Continuity check - 12•2Control arm - 10•4, 10•5Conversion factors - REF•17Coolant - 1•3, 1•8Coolant pump - 3•5Coolant temperature sender unit - 3•6Coolant temperature sensor - 6•2Cooling fan - 3•4Cooling, heating and air conditioning

systems - 1•21, 1•24, 3•1 et seqCooling system fault finding - REF•12Crankshaft - 2A•12, 2A•13, 2A•19, 2B•13,

2B•17, 2B•19, 2B•20Cruise control - 12•3, 12•8Crushing - 0•5Cushion - 11•9CV joints - 8•2, 8•8, 8•9Cylinder head - 2A•13, 2B•7, 2B•10, 2B•12Cylinder honing - 2B•15

DDents in bodywork - 11•2Differential (final drive) - 8•2, 8•10, 8•11Differential oil - 1•3, 1•19, 1•26Direction indicators - 12•2, 12•3Discs - 1•22, 9•5Distributor - 1•18, 5•4Door - 11•6, 11•8, REF•2Drivebelts - 1•14Driveplate - 2A•18Driveshafts - 1•22, 8•2, 8•9Drums - 1•23

REF•26 IndexEEarth check - 12•2Electric fan - 3•4Electric shock - 0•5Electric windows - 12•9Electrical equipment - REF•2Electrical system fault finding - 12•1Electronic control system - 4•3, 4•14Electronic control unit (ECU) - 6•1Engine fault finding - REF•10Engine tune-up - 1•7Engine electrical systems - 5•1 et seqEngine electrical systems fault finding -

REF•11Engine management and emission control

systems - 6•1 et seqEngine oil - 1•3, 1•7, 1•11Environmental considerations - REF•8Evaporative emissions control (EVAP)

system - 1•26, 6•5Evaporator - 3•10Exhaust emission checks - REF•4Exhaust manifold - 2A•6Exhaust system - 1•21, 4•20, REF•3

FFan - 3•4, 3•5Fault finding - REF•9 et seqFault finding - automatic transmission -

7B•2, REF•13Fault finding - braking system - REF•14Fault finding - clutch - REF•12Fault finding - cooling system - REF•12Fault finding - electrical system - 12•1,

REF•11Fault finding - engine - REF•10Fault finding - fuel system - 4•21, REF•12Fault finding - manual transmission -

REF•13Fault finding - suspension and steering -

REF•15Filling - 11•3Final drive - 8•2, 8•10, 8•11Final drive oil - 1•3, 1•19, 1•26Fire - 0•5Flexible coupling - 8•7Fluid level checks - 1•7Fluid seals - 7B•5Flywheel - 2A•18Fuel and exhaust systems - 1•20, 4•1 et

seq, REF•4Fuel system fault finding - REF•12Fuel filter - 1•25Fuel hoses - 1•14Fuel injection system - 4•3, 4•14Fuel injection system - fault finding - 4•21Fuel injectors - 4•18Fuel level sender unit - 4•5, 4•6Fuel lines and fittings - 4•7Fuel pressure - 4•3Fuel pressure regulator - 4•16Fuel pump - 4•3, 4•4, 4•5Fuel tank - 4•7, 4•8Fume or gas intoxication - 0•5Fuses - 12•2

GGaiters - 1•22, 8•9, 10•13Gashes in bodywork - 11•2Gaskets - REF•8Gear lever - 7A•1Gearbox - See Manual transmissionGearbox oil - 1•3, 1•19, 1•25General engine overhaul procedures -

2B•1 et seqGlass - 11•4, 11•8Glossary of technical terms - REF•20Grille - 11•4

HHandbrake - 1•23, 9•2, 9•12, REF•1Handbrake fault - REF•14Handles - 11•8Hazard warning flasher - 12•2HC emissions - REF•4Headlights - 12•3, 12•5, 12•6Heated rear window - 12•8Heater - 3•2, 3•7, 3•8Hinges - 11•4HT leads - 1•18Hubs - 10•8, 10•11, REF•3Hydraulic servo - 9•11Hydraulic tappets - 2B•11Hydrofluoric acid - 0•5

IIdle air stabiliser valve - 4•18Idle speed adjustment - 1•15Ignition coil - 5•5Ignition control unit - 5•6, 5•7Ignition sensors - 5•8Ignition switch - 12•3Ignition system - 5•3Ignition timing - 5•4Ignition timing sensors - 6•4Impulse generator - 5•6, 5•7In-car engine repair procedures - 2A•1 et

seqIndicators - 12•2, 12•3Information sensors - 6•2Injectors - 4•18Input shaft - 7A•2Instrument cluster - 12•4Instrument panel language display - 0•7Intake manifold - 2A•4Intermediate shaft - 2A•12, 2B•14, 2B•19Introduction to the BMW 3- and 5-Series -

0•4

JJacking - 0•8Joint mating faces - REF•8Jump starting - 0•9

KKickdown cable - 7B•3

LL-Jetronic fuel injection system - 4•14,

4•19Language display - 0•7Latch - 11•8Leaks - 0•10, 7B•3, REF•12, REF•13Locknuts, locktabs and washers - REF•8Locks - 11•4, 11•8Lubricants - REF•18

MMain bearings - 2B•17, 2B•19Manifolds - 2A•4, 2A•6Manual transmission - 7A•1 et seqManual transmission fault finding - REF•13Manual transmission oil - 1•3, 1•19, 1•25Master cylinder - 8•3, 9•9Mechanical fan - 3•4, 3•5Mirrors - 11•8, REF•1Misfire - REF•11Mixture - REF•4MOT test checks - REF•1 et seqMotronic engine management system -

6•1Motronic fuel injection system - 4•14, 4•19Mountings - 2A•19, 7A•3

OOil - differential - 1•19, 1•26Oil - engine - 1•3, 1•7, 1•11Oil - final drive - 1•3Oil - manual transmission - 1•3, 1•19, 1•25Oil filter - 1•11, 1•12Oil pump - 2A•16Oil seals - 2A•12, 2A•13, 2A•19, 2B•20,

7A•2, 7B•5, 8•10, 8•12, REF•8Open-circuit - 12•2Output shaft - 7A•2, 7B•5Overcooling - REF•12Overheating - REF•12Oxygen sensor - 6•2

PPads - 9•2, 9•3Pedals - 8•3, 9•13Pinion oil - 8•12Pinking - REF•11Piston rings - 2B•18Pistons - 2B•12, 2B•16, 2B•21Plastic components - 11•3Poisonous or irritant substances - 0•5Position sensors - 5•8Positive crankcase ventilation (PCV)

system - 6•4Power steering - 1•14, 10•15, 10•16Power steering fluid - 1•12Propeller shaft - 8•2, 8•6, 8•8Pulse sensor - 5•8Purge valve - 6•5

REF•27

REF

IndexRRadiator - 3•3, 11•4Radio - 12•4Receiver-drier - 3•9Regulator (voltage) - 5•10Regulator (window) - 11•8Relays - 12•2Repair procedures - REF•8Respraying - 11•3Reversing light switch - 7B•4Rocker arms - 2B•11Rotor - 1•18Routine maintenance and servicing - 1•1

et seqRoutine maintenance - air conditioning

system - 3•8Routine maintenance - bodywork and

underframe - 11•1Routine maintenance - hinges and locks -

11•4Routine maintenance - interior trim - 11•2Routine maintenance - upholstery and

carpets - 11•2Rust holes in bodywork - 11•2

SSafety first! - 0•5Scalding - 0•5Scratches in bodywork - 11•2Screw threads and fastenings - REF•8Seat belt - 11•9, REF•2Seats - 11•9, REF•2Selector lever - 7B•3, 7B•5Selector shaft - 7A•2Service Indicator (SI) board - 12•4Service indicator light - 1•26Servo - 9•2, 9•10, 9•11Shock absorber - 1•21, 10•7, 10•8, 10•9,

REF•2, REF•3Shoes - 9•7Short-circuit - 12•2

Silencer - 4•20Slave cylinder - 8•3Spares - REF•19Spark plug - 1•17, 1•18Speed sensors - 5•8Springs - 10•7, 10•9, REF•3Starter inhibitor - 7B•4Starter motor - 5•12Starter motor fault - REF•10Starting system - 5•11Steering box - 10•15Steering column - 11•9, 12•3, REF•1Steering gear - 10•12, 10•13, REF•3Steering linkage - 10•14Steering wheel - 10•16, REF•1Stop-light switch - 9•13Struts - 1•21, 10•6, 10•7Sump - 2A•15Supplemental Restraint System (SRS) -

12•8Suspension and steering systems - 1•21,

1•22, 10•1 et seq, REF•2, REF•3Suspension and steering fault finding -

REF•15Switches - 7B•4, 9•13, 12•3

TTailgate - 11•6Tappets - 2B•11Thermostat - 3•2Thermotime switch - 4•17, 4•18Throttle body - 4•16Throttle linkage - 1•20Throttle Position Sensor (TPS) - 6•3Throttle positioner - 4•13, 4•14Thrust arm - 10•5Timing - 5•4Timing belt - 1•26, 2A•8, 2A•9Timing chain - 2A•6, 2A•8Timing sensors - 6•4Tools - REF•5, REF•7, REF•8Top Dead Centre (TDC) for No 1 piston -

2A•3

Torque converter - 7B•5Towing - 0•8Track rod ends - 10•13Trailing arms - 10•10Transmission - See Manual transmission or

Automatic transmissionTrim - 11•2, 11•6Tyres - 1•9, 1•14, 10•16, REF•4, REF•15

UUnderframe - 11•1Universal joints - 8•8Upholstery - 11•2

VVacuum hoses - 1•14Vacuum servo - 9•10Valve clearances - 1•19Valve cover - 2A•4Valves - 2B•10, 2B•11Vehicle identification - REF•2, REF•19Voltage checks - 12•1Voltage regulator - 5•10

WWasher fluid - 1•9Water pump - 3•5Weekly checks - 1•7 et seqWheel alignment - 10•17Wheel bearings - 10•8, 10•11, REF•3Wheel changing - 0•8Wheels - 10•16, REF•4Windows - 11•8, 12•9Windscreen - REF•1Wiper blades - 1•23Wiper motor - 12•7Wiring diagrams - 12•9 et seqWorking faclities - REF•7

REF•30

Almost every car you’ve ever loved, loathed or desired is gathered under one roof at the Haynes MotorMuseum. Over 300 immaculately presented cars and motorbikes represent every aspect of our motoring

heritage, from elegant reminders of bygone days, such as the superb Model J Duesenberg to curiosities likethe bug-eyed BMW Isetta. There are also many old friends and flames. Perhaps you remember the 1959 Ford

Popular that you did your courting in? The magnificent ‘Red Collection’ is a spectacle of classic sports carsincluding AC, Alfa Romeo, Austin Healey, Ferrari, Lamborghini, Maserati, MG, Riley, Porsche and Triumph.

A Perfect Day OutEach and every vehicle at the Haynes Motor Museum has played its part in the history and culture of

Motoring. Today, they make a wonderful spectacle and a great day out for all the family. Bring the kids, bringMum and Dad, but above all bring your camera to capture those golden memories for ever. You will also find

an impressive array of motoring memorabilia, a comfortable 70 seat video cinema and one of the mostextensive transport book shops in Britain. The Pit Stop Cafe serves everything from a cup of tea to

wholesome, home-made meals or, if you prefer, you can enjoy the large picnic area nestled in the beautifulrural surroundings of Somerset.

The Museum is situated on the A359 Yeovil to Frome road at Sparkford, just off the A303 in Somerset. It is about 40 miles south of Bristol, and 25 minutes drive from the M5 intersection at Taunton.

Open 9.30am - 5.30pm (10.00am - 4.00pm Winter) 7 days a week, except Christmas Day, Boxing Day and New Years DaySpecial rates available for schools, coach parties and outings Charitable Trust No. 292048

>John Haynes O.B.E.,

Founder andChairman of the

museum at the wheelof a Haynes Light 12.

<Graham Hill’s LolaCosworth Formula 1car next to a 1934Riley Sports.

<The Model J DuesenbergDerham Tourster. Only eight of thesemagnificent cars wereever built – this is theonly example to be foundoutside the UnitedStates of America

Preserving Our Motoring Heritage

BMW 3- & 5-Series Service and Repair Manual E28 E30 E34... · by this manual) was introduced....

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