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COOLING SYSTEM

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COOLANTLOW LEVEL AERATION . . . . . . . . . 27

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VISCOUS FAN DRIVE . . . . . . . . . . . . . . . . . . . . . 53

AN COOLING SYSTEM 7 - 1COOLING SYSTEMDEAERATION . . . . . . . . . . 27ERVICE PROCEDURESCOOLANTROUTINE LEVEL CHECK. . . . . . . . . 27COOLANT SERVICE . . . . . . . . . . . . . . . . . . . . . . 27COOLANTADDING ADDITIONAL. . . . . . . . . . . 28

ELECTRIC FAN . . . . . . . . . . . . . . . . . . . . . . . . . . 54CLEANING AND INSPECTION

RADIATOR CAP . . . . . . . . . . . . . . . . . . . . . . . . . 55RADIATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55WATER PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . 55TABLE OF

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ESCRIPTION AND OPERATIONCOOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . 2COOLANT RESERVE/OVERFLOW SYSTEM . . . . . 5ENGINE ACCESSORY DRIVE BELTS. . . . . . . . . . . 5RADIATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5WATER PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . 6WATER PUMP BYPASS4.7L. . . . . . . . . . . . . . . 6WATER PUMP BYPASS3.9/5.9L ENGINES. . . . 6THERMOSTAT3.9L/5.9L ENGINES . . . . . . . . . . 7THERMOSTAT4.7L ENGINE . . . . . . . . . . . . . . . 7AUTOMATIC TRANSMISSION OIL COOLERS. . . . 8AUTOMATIC BELT TENSIONER . . . . . . . . . . . . . . 8BLOCK HEATER . . . . . . . . . . . . . . . . . . . . . . . . . . 9RADIATOR PRESSURE CAP . . . . . . . . . . . . . . . . 10HOSE CLAMPS . . . . . . . . . . . . . . . . . . . . . . . . . . 10VISCOUS FAN DRIVE . . . . . . . . . . . . . . . . . . . . . 11COOLING SYSTEM FAN . . . . . . . . . . . . . . . . . . . 11IAGNOSIS AND TESTINGON-BOARD DIAGNOSTICS (OBD) . . . . . . . . . . . 12DRB SCAN TOOL . . . . . . . . . . . . . . . . . . . . . . . . 13WATER PUMP TESTS. . . . . . . . . . . . . . . . . . . . . 13PRELIMINARY CHECKS . . . . . . . . . . . . . . . . . . . 14COOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . 15ELECTRIC COOLING FAN . . . . . . . . . . . . . . . . . . 20RADIATOR COOLANT FLOW CHECK . . . . . . . . . 21COOLING SYSTEMTESTING FOR LEAKS . . . . 21VISCOUS FAN DRIVE3.9L/4.7L and 5.9L

ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23ACCESSORY DRIVE BELT DIAGNOSIS. . . . . . . . 24THERMOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 26RADIATOR CAP-TO-FILLER NECK

SEALPRESSURE RELIEF CHECK. . . . . . . . . 26RADIATOR CAPPRESSURE TESTING. . . . . . . 26NTENTS

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COOLANT LEVEL CHECK . . . . . . . . . . . . . . . . . . 28COOLING SYSTEMDRAINING AND

FILLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28COOLING SYSTEMCLEANING/REVERSE

FLUSHING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29COOLANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30COOLANT SELECTION AND ADDITIVES . . . . . . 30

REMOVAL AND INSTALLATIONCOOLANT RESERVE/OVERFLOW TANK . . . . . . . 30WATER PUMP2.5L ENGINE . . . . . . . . . . . . . . 30WATER PUMP3.9L/5.9L ENGINES . . . . . . . . . 32WATER PUMP 4.7L ENGINES . . . . . . . . . . . . . . 35WATER PUMP BYPASS HOSE3.9/5.9L

ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37THERMOSTAT3.9L/5.9L ENGINES . . . . . . . . . 39THERMOSTAT2.5L ENGINE . . . . . . . . . . . . . . 42THERMOSTAT 4.7L ENGINE. . . . . . . . . . . . . . 43TRANSMISSION OIL COOLER LINES. . . . . . . . . 44RADIATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44ENGINE BLOCK HEATER . . . . . . . . . . . . . . . . . . 46ACCESSORY DRIVE BELT2.5L ENGINE . . . . . 47ACCESSORY BELT REPLACEMENT4.7L

ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48ACCESSORY DRIVE BELT3.9L/5.9L

ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49ACCESSORY DRIVE BELT TENSIONER2.5L . . 50AUTOMATIC BELT TENSIONER 3.9L/5.9L

ENGINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50AUTOMATIC BELT TENSIONER4.7L

ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51IDLER PULLEY2.5L/3.9L/5.9L ENGINES . . . . 51IDLER PULLEY4.7L ENGINE NON A/C. . . . . . 52RADIATOR DRAINCOCK . . . . . . . . . . . . . . . . . . . 52

FAN BLADE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55SPECIFICATIONS

COOLING SYSTEM CAPACITIES. . . . . . . . . . . . . 56ACCESSORY DRIVE BELT TENSION2.5L

ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . . 56SPECIAL TOOLS

COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

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7 - 2 COOLING SYSTEM ANESCRIPTION AND OPERATION

OOLING SYSTEM

ESCRIPTIONThe cooling system regulates engine operating tem-

erature. It allows the engine to reach normal oper-ting temperature as quickly as possible. It also

Fig. 1 Engine Cooling Syste1 WATER CONTROL VALVE2 TO WATER PUMP3 THERMOSTAT HOUSING4 RADIATOR CAP5 RADIATORmaintains normal operating temperature and pre-vents overheating.

The cooling system also provides a means of heat-ing the passenger compartment and cooling the auto-matic transmission fluid (if equipped). The coolingsystem is pressurized and uses a centrifugal waterpump to circulate coolant throughout the system.

low2.5L EngineTypical6 TO COOLANT RESERVE BOTTLE7 TO WATER PUMP8 TO HEATER CORE9 FROM HEATER CORE

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AN COOLING SYSTEM 7 - 3

D d)An optional factory installed maximum duty cool-ng package is available on most models. This pack-ge will provide additional cooling capacity forehicles used under extreme conditions such asrailer towing in high ambient temperatures.

Fig. 2 Engine Cooling System1 HEATER2 BYPASS*

ESCRIPTION AND OPERATION (Continue3.9L/5.9L EnginesTypical3 CROSSFLOW RADIATORFlow

7 - 4 COOLING SYSTEM AN

D d)Fig. 3 Engine Cooling Syste1 LH CYL. HEAD2 BLEED3 THERMOSTAT LOCATION4 RH CYL. HEAD

ESCRIPTION AND OPERATION (Continuelow4.7L EngineTypical5 RH BANK CYL. BLOCK6 LH BANK CYL. BLOCK7 COOLANT TEMP. SENSORm F

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D d)OOLANT RESERVE/OVERFLOW SYSTEM

ESCRIPTIONThe coolant reserve/overflow tank is integral to the

pper fan shroud assembly and is made of high tem-erature plastic.

PERATIONThe coolant reserve/overflow system works in con-

unction with the radiator pressure cap. It utilizeshermal expansion and contraction of coolant to keepoolant free of trapped air. It provides a volume forxpansion and contraction of coolant. It also provides

convenient and safe method for checking coolantevel and adjusting level at atmospheric pressure.his is done without removing the radiator pressureap. The system also provides some reserve coolanto the radiator to cover minor leaks and evaporationr boiling losses.As the engine cools, a vacuum is formed in the

ooling system of both the radiator and engine. Cool-nt will then be drawn from the coolant tank andeturned to a proper level in the radiator.

Fig. 4 Upper Fan Shroud with Integral CoolantReserve/Overflow System

1 RADIATOR2 WASHER FLUID RESERVOIR3 COOLANT OVERFLOW/RESERVOIR4 FAN SHROUD (UPPER)5 SCREW6 INTERLOCKING PINS7 FAN SHROUD (LOWER)

ESCRIPTION AND OPERATION (ContinueENGINE ACCESSORY DRIVE BELTS

DESCRIPTION

CAUTION: When installing a serpentine accessorydrive belt, the belt MUST be routed correctly. If not,the engine may overheat due to water pump rotat-ing in wrong direction. Refer to the appropriateengine Belt Schematic in this Section for the cor-rect belt routing. Or, refer to the Belt Routing Labellocated in the engine compartment.

The accessory drive belt is made of rubber and hasgrooves in only one side, these grooves mate to thegrooves in the accessories pulleys for maximum beltcontact and belt alignment.

The accessory drive components are operated by asingle, crankshaft driven, serpentine drive belt on allengines. An automatic belt tensioner is also used tomaintain correct belt tension at all times.

RADIATOR

DESCRIPTIONThe radiator is a aluminum cross-flow design with

horizontal tubes through the radiator core and verti-cal plastic side tanks.

OPERATIONThe radiator supplies sufficient heat transfer using

the cooling fins interlaced between the horizontaltubes in the radaitor core to cool the engine andautomatic transmission oil (if equipped).

Fig. 5 RadiatorTypical1 RADIATOR2 A/C CONDENSER (IF EQUIPPED)3 TRANSMISSION AUXILIARY OIL COOLER

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D d)ATER PUMP

ESCRIPTIONThe water pump is located on the engine front

over, and has an integral pulley attached (Fig. 6).The water pump impeller is pressed onto the rear

f a shaft that rotates in a bearing pressed into theater pump body. The body has a small hole for ven-

ilation. The water pump seals are lubricated byntifreeze in the coolant mixture. Additional lubrica-ion is not necessary.

PERATIONA centrifugal water pump circulates coolant

hrough the water jackets, passages, intake manifold,adiator core, cooling system hoses and heater core,his coolant absorbs the heat generated when thengine is running. The pump is driven by the enginerankshaft via a drive belt.

ATER PUMP BYPASS4.7L

ESCRIPTIONThe 4.7L engine uses an internal water/coolant

ypass system. The design uses galleries in the tim-ng chain cover to circulate coolant during enginearm-up preventing the coolant from flowing

hrough the radiator. The thermostat uses a stubhaft located at the rear of the thermostat (Fig. 7) toontrol flow through the bypass gallery.

Fig. 6 Water Pump LocationTypical1 WATER PUMP BYPASS HOSE2 FAN BLADE ASSEMBLY3 VISCOUS FAN DRIVE4 WATER PUMP AND PULLEY

ESCRIPTION AND OPERATION (ContinueOPERATIONWhen the thermostat is in the closed position the

bypass gallery is not obstructed allowing 100% flow.When the thermostat is in the open position the stubshaft enters the bypass gallery obstructing bypasscoolant flow by 50%. This design allows the coolantto reach operating temperature quickly when cold,while adding extra cooling during normal tempera-ture operation.

WATER PUMP BYPASS3.9/5.9L ENGINES

DESCRIPTIONA rubber water pump bypass hose (Fig. 8) is used

between the intake manifold and water pump on all3.9/5.9L engines.

Fig. 7 Water/Coolant Bypass Flow and Thermostat4.7L Engine

1 FROM HEATER2 FROM RADIATOR3 TO WATER PUMP4 ENGINE BYPASS5 THERMOSTAT

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D d)PERATIONWhen the thermostat is in the closed position the

ypass hose allows the water pump to circulate thengine coolant through the cylinder block while athe same time preventing the coolant from flowinghrough the radiator, this allows the coolant to heatp quicker thus bring the engine to operating tem-erature faster.

HERMOSTAT3.9L/5.9L ENGINES

ESCRIPTION

AUTION: Do not operate an engine without a ther-ostat, except for servicing or testing.

The thermostat on all gas powered engines isocated beneath the thermostat housing at the frontf the intake manifold (Fig. 9).The thermostat is a wax pellet driven, reverse pop-

et choke type.Coolant leakage into the pellet container will cause

he thermostat to fail in the open position. Thermo-tats very rarely stick. Do not attempt to free a ther-ostat with a prying device.The same thermostat is used for winter and sum-er seasons. An engine should not be operated with-

ut a thermostat, except for servicing or testing.perating without a thermostat causes longer enginearmup time, unreliable warmup performance,

ncreased exhaust emissions and crankcase condensa-ion that can result in sludge formation.

Fig. 8 Water Pump Bypass Hose3.9L/5.9L Engines1 WATER PUMP BYPASS HOSE2 FAN BLADE ASSEMBLY3 VISCOUS FAN DRIVE4 WATER PUMP AND PULLEY

ESCRIPTION AND OPERATION (ContinueOPERATIONThe wax pellet is located in a sealed container at

the spring end of the thermostat. When heated, thepellet expands, overcoming closing spring tensionand water pump pressure to force the valve to open.

THERMOSTAT4.7L ENGINE

DESCRIPTION

CAUTION: Do not operate an engine without a ther-mostat, except for servicing or testing.

A pellet-type thermostat controls the operatingtemperature of the engine by controlling the amountof coolant flow to the radiator. On all engines thethermostat is closed below 195F (90C). Above thistemperature, coolant is allowed to flow to the radia-tor. This provides quick engine warm up and overalltemperature control. On the 4.7L engine the thermo-stat is designed to block the flow of the coolantbypass journal by 50% instead of completely blockingthe flow. This design controls coolant temperaturemore accurately (Fig. 10).

Fig. 9 Thermostat3.9L V-6 or 5.9L V-8 GasPowered Engines

1 THERMOSTAT HOUSING2 GASKET3 INTAKE MANIFOLD4 THERMOSTAT5 MACHINED GROOVEThe same thermostat is used for winter and sum-mer seasons. An engine should not be operated with-out a thermostat, except for servicing or testing.

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D d)perating without a thermostat causes other prob-ems. These are: longer engine warmup time, unreli-ble warmup performance, increased exhaustmissions and crankcase condensation. This conden-ation can result in sludge formation.

PERATIONThe wax pellet is located in a sealed container at

he spring end of the thermostat. When heated, theellet expands, overcoming closing spring tensionnd water pump pressure to force the valve to open.

UTOMATIC TRANSMISSION OIL COOLERS

ESCRIPTION

AUTION: On in-radiator type oil coolers, if trans-ission oil cooler is leaking, engine coolant may

nter cooler, or transmission oil may enter engineooling system. Both engine cooling system and

Fig. 10 Thermostat Cross Section View 4.7L1 FROM HEATER2 FROM RADIATOR3 TO WATER PUMP4 ENGINE BYPASS5 THERMOSTAT

ESCRIPTION AND OPERATION (Continueransmission oil circuit should be drained, flushed,nd inspected.There are two types of transmission oil coolersused. One type of cooler is the in-radiator type or oilto coolant type. This type oil cooler is not serviceable.The second type used is a remote type auxiliary oilcooler or oil to air cooler. The oil to air type cooler islocated in front of the radiator, and is serviceable.

AUTOMATIC BELT TENSIONER

DESCRIPTIONCorrect drive belt tension is required to ensure

optimum performance of the belt driven engine acces-sories. If specified tension is not maintained, beltslippage may cause; engine overheating, lack of

Fig. 11 Oil Flow to CoolerTop View (Typical)1 TRANSMISSION OIL COOLER2 AUTOMATIC TRANSMISSION3 RETURN LINE4 PRESSURE LINE

Fig. 12 Auxiliary Transmission Oil CoolerTypical1 RADIATOR2 A/C CONDENSER (IF EQUIPPED)3 TRANSMISSION AUXILIARY OIL COOLERpower steering assist, loss of air conditioning capac-ity, reduced generator output rate, and greatlyreduced belt life.

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D d)It is not necessary to adjust belt tension on the.9L, 4.7L or 5.9L engines. These engines arequipped with an automatic belt tensioner (Fig. 13)Fig. 14). The tensioner maintains correct belt ten-ion at all times. Due to use of this belt tensioner, doot attempt to use a belt tension gauge on 3.9L, 4.7Lr 5.9L engines.

PERATIONThe automatic belt tensioner maintains belt ten-

ion by using internal spring pressure, a pivotingrm and pulley to press against the drive belt.

Fig. 13 Automatic Belt Tensioner3.9L and 5.9LEngines

1 AUTOMATIC TENSIONER2 COIL AND BRACKET3 SCREW AND WASHER

Fig. 14 Automatic Belt Tensioner4.7L Engine1 AUTOMATIC TENSIONER ASSEMBLY

ESCRIPTION AND OPERATION (ContinueBLOCK HEATER

DESCRIPTION

WARNING: DO NOT OPERATE ENGINE UNLESSBLOCK HEATER CORD HAS BEEN DISCONNECTEDFROM POWER SOURCE AND SECURED IN PLACE.THE POWER CORD MUST BE SECURED IN ITSRETAINING CLIPS AND ROUTED AWAY FROMEXHAUST MANIFOLDS AND MOVING PARTS.

An optional engine block heater is available for allmodels. The heater is equipped with a power cord.The cord is attached to an engine compartment com-ponent with tie-straps. The heater is mounted in acore hole of the engine cylinder block in place of afreeze plug with the heating element immersed inengine coolant.

OPERATIONThe heater warms the engine providing easier

engine starting and faster warm-up in low tempera-tures. The power cord must be connected to agrounded 110-120 volt AC electrical outlet with agrounded, three wire extension cord, this providesthe electricity to warm the heating element.

Fig. 15 Block Heater4.7L1 ENGINE BLOCK HEATER

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D d)ADIATOR PRESSURE CAP

ESCRIPTIONAll radiators are equipped with a pressure cap.

his cap releases pressure at some point within aange of 124-to-145 kPa (18-to-21 psi). The pressureelief point (in pounds) is engraved on top of the capThe cooling system will operate at pressures

lightly above atmospheric pressure. This results in aigher coolant boiling point allowing increased radi-tor cooling capacity. The cap contains a spring-oaded pressure relief valve. This valve opens whenystem pressure reaches the release range of 124-to-45 kPa (18-to-21 psi).A rubber gasket seals the radiator filler neck. This

s done to maintain vacuum during coolant cool-downnd to prevent leakage when system is under pres-ure.

Fig. 16 Radiator Pressure CapTypical1 FILLER NECK SEAL2 VACUUM VENT VALVE3 PRESSURE RATING4 PRESSURE VALVE

ESCRIPTION AND OPERATION (ContinueOPERATIONA vent valve in the center of the cap will remain

shut as long as the cooling system is pressurized. Asthe coolant cools, it contracts and creates a vacuumin cooling system. This causes the vacuum valve toopen and coolant in reserve/overflow tank to bedrawn through connecting hose into radiator. If thevacuum valve is stuck shut, or overflow hose iskinked, radiator hoses will collapse on cool-down.

HOSE CLAMPS

DESCRIPTIONThe cooling system utilizes both worm drive and

spring type hose clamps. If a spring type clampreplacement is necessary, replace with the originalMopart equipment spring type clamp.

CAUTION: A number or letter is stamped into thetongue of constant tension clamps. If replacementis necessary, use only a original equipment clampwith matching number or letter (Fig. 17).

OPERATIONThe worm type hose clamp uses a specified torque

value to maintain proper tension on a hose connec-tion.

The spring type hose clamp applies constant ten-sion on a hose connection. To remove a spring typehose clamp, only use constant tension clamp pliersdesigned to compress the hose clamp.

Fig. 17 Spring Clamp Size Location1 SPRING CLAMP SIZE LOCATION

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D d)ISCOUS FAN DRIVE

ESCRIPTION

AUTION: Engines equipped with accessory driveelts have reverse rotating fans and viscous fanrives. They are marked with the word REVERSE toesignate their usage. Installation of the wrong fanr viscous fan drive can result in engine overheat-

ng.

The thermal viscous fan drive is a silicone-fluid-illed coupling used to connect the fan blades to theater pump shaft. The coupling allows the fan to beriven in a normal manner. This is done at lowngine speeds while limiting the top speed of the fano a predetermined maximum level at higher enginepeeds.On all 3.9L, 5.9L and 4.7L an electrical cooling fan

ocated in the fan shroud aids in low speed cooling, Its designed to augment the viscous fan, However, itoes not replace the viscous fan.A thermostatic bimetallic spring coil is located on

he front face of the viscous fan drive unit. Thispring coil reacts to the temperature of the radiatorischarge air. It engages the viscous fan drive forigher fan speed if the air temperature from theadiator rises above a certain point. Until additionalngine cooling is necessary, the fan will remain at aeduced rpm regardless of engine speed.

Fig. 18 Fan Blade/Viscous Fan Drive3.9L/4.7L/5.9LEngines

1 VISCOUS FAN DRIVE2 FAN BLADE3 SCREW AND WASHER

ESCRIPTION AND OPERATION (ContinueOPERATIONWhen sufficient heat is present, the viscous fan

drive will engage. This is when the air flowingthrough the radiator core causes a reaction to thebimetallic coil. It then increases fan speed to providethe necessary additional engine cooling.

Once the engine has cooled, the radiator dischargetemperature will drop. The bimetallic coil againreacts and the fan speed is reduced to the previousdisengaged speed.

COOLING SYSTEM FAN

DESCRIPTIONThe fan is electrically controlled by the powertrain

control module (PCM) through the fan control relay.This relay is located in the power distribution center(PDC). For the location of the relay within the PDC,refer to label on PDC cover.

Fig. 19 Viscous Fan Drive3.9L/4.7L/5.9L EnginesTypical

1 VISCOUS FAN DRIVE2 THERMOSTATIC SPRING3 MOUNTING NUT TO WATER PUMP HUB

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D d)PERATIONThe PCM regulates fan operation based on input

rom the engine coolant temperature sensor and vehi-le speed.The fan is not energized during engine cranking

egardless of the electrical input from the engineoolant temperature sensor. However, if engine oper-ting conditions warrant fan engagement, the fanill run once engine starts.The fan is energized whenever the engine is run-

ing and the air conditioning is selected on the tem-erature control panel.

Fig. 20 Electric Fan AssemblyTypical1 RADIATOR2 ELECTRIC FAN ASSEMBLY

Fig. 21 Power Distribution Center (PDC)1 POWER DISTRIBUTION CENTER (PDC)

ESCRIPTION AND OPERATION (ContinueIf the A/C is not selected the fan operates when theoolant temperature is above 104 C (220 F). Theame is true for vehicles not equipped with A/C. Thefan will turn off when coolant temperature drops to102 C (216 F).

DIAGNOSIS AND TESTING

ON-BOARD DIAGNOSTICS (OBD)

FOR CERTAIN COOLING SYSTEM COMPONENTSThe powertrain control module (PCM) has been

programmed to monitor certain cooling system com-ponents:

NOTE: If the engine has remained cool for too longa period, such as with a stuck open thermostat, aDiagnostic Trouble Code (DTC) number 17 can beobserved at the malfunction indicator lamp. Thislamp is displayed on the instrument panel as theCHECK ENGINE lamp (Fig. 22).

If the problem is sensed in a monitored circuitoften enough to indicate an actual problem, a DTC isstored. The DTC will be stored in the PCM memoryfor eventual display to the service technician. If theproblem is repaired or ceases to exist, the PCM can-cels the DTC after 51 engine starts.

Certain criteria must be met for a DTC to beentered into PCM memory. The criteria may be aspecific range of engine rpm, engine temperatureand/or input voltage to the PCM.

A DTC indicates that the PCM has recognized anabnormal signal in a circuit or the system. A DTCmay indicate the result of a failure, but never iden-tify the failed component directly.

It is possible that a DTC for a monitored circuitmay not be entered into memory even though a mal-

Fig. 22 Check Engine Lamp Location1 CHECK ENGINE LAMPfunction has occurred. Refer to On- Board Diagnos-

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Dics (OBD) in Group 25, Emission Control Systemsor additional information.

CCESSING DIAGNOSTIC TROUBLE CODESA stored Diagnostic Trouble Code (DTC) can be dis-

layed by cycling the ignition key On-Off-On-Off-Onithin three seconds and observing the malfunction

ndicator lamp. This lamp is displayed on the instru-ent panel as the CHECK ENGINE lamp (Fig. 22).They can also be displayed through the use of theiagnostic Readout Box (DRB) scan tool. The DRB

onnects to the data link connector, left of the steer-ng column above the brake pedal (Fig. 23). For oper-tion of the DRB, refer to the appropriate Powertrainiagnostic Procedures service manual.

EXAMPLES: If the lamp (Fig. 22) flashes 1 time, pauses and

lashes 2 more times, a flashing Diagnostic Troubleode (DTC) number 12 is indicated. If this code isbserved, it is indicating that the battery has beenisconnected within the last 50 key-on cycles. Itould also indicate that battery voltage has been dis-onnected to the PCM. In either case, other DTCsay have been erased. If the lamp flashes 1 time, pauses and flashes 7ore times, a flashing Diagnostic Trouble Code

DTC) number 17 is indicated.After any stored DTC information has been

bserved, the display will end with a flashing DTCumber 55. This will indicate the end of all stored

Fig. 23 Data Link Connector Location1 HEADLAMP SWITCH2 DATA LINK CONNECTOR (LEFT SIDE OF COLUMN ABOVE

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IAGNOSIS AND TESTING (Continued)nformation.ERASING TROUBLE CODESAfter the problem has been repaired, use the DRB

scan tool to erase a DTC. Refer to the appropriatePowertrain Diagnostic Procedures service manual foroperation of the DRB scan tool.

DRB SCAN TOOLFor operation of the DRB scan tool, refer to the

appropriate Powertrain Diagnostic Procedures ser-vice manual.

WATER PUMP TESTS

LOOSE IMPELLER4.7L

NOTE: Due to the design of the 4.7L engine waterpump, testing the pump for a loose impeller mustbe done by verifying coolant flow in the radiator. Toaccomplish this refer to the following procedure.

DO NOT WASTE reusable coolant. If solution isclean, drain coolant into a clean container for reuse.

(1) Drain coolant until the first row of cores is vis-ible in the radiator.

(2) Leaving the radiator cap off, start the engine(3) While looking into the radiator through the

radiator fill neck, raise engine rpm to 2000 RPM.Observe the flow of coolant from the first row ofcores.

(4) If there is no flow or very little flow visable,replace the water pump.

INSPECTING FOR INLET RESTRICTIONSInadequate heater performance may be caused by

a metal casting restriction in the heater hose inlet.DO NOT WASTE reusable coolant. If solution is

clean, drain the coolant into a clean container forreuse.

WARNING: DO NOT LOOSEN THE RADIATORDRAINCOCK WITH THE SYSTEM HOT AND UNDERPRESSURE. SERIOUS BURNS FROM THE COOL-ANT CAN OCCUR.

(1) Drain sufficient coolant from the radiator todecrease the level below the heater hose inlet. On4.7L engines this requires complete draining.

(2) Remove the heater hose.(3) Inspect the inlet for metal casting flash or

other restrictions.

NOTE: On 4.7L engine remove the fitting from thetiming chain cover, If the restriction is in the timingchain cover, remove the timing chain cover. Refer

to Timing Chain Cover in Group 9 Engine, for pro-cedure.

PRELIMINARY CHECKS

ENGINE COOLING SYSTEM OVERHEATINGEstablish what driving conditions caused the com-

plaint. Abnormal loads on the cooling system such asthe following may be the cause:

PROLONGED IDLE, VERY HIGH AMBIENTTEMPERATURE, SLIGHT TAIL WIND AT IDLE,SLOW TRAFFIC, TRAFFIC JAMS, HIGH SPEED,OR STEEP GRADES.

Driving techniques that avoid overheating are: Idle with A/C off when temperature gauge is at

end of normal range. If vehicle is equipped with a 2.5L 4-cylinder

engine, do not increase engine speed for more airflow. Cooling systems with electric cooling fans do notrespond to engine rpm. The added cooling fromhigher coolant flow is more than offset by increasedheat from higher engine output.

If vehicle is equipped with a V-6 or V-8 engine,increasing engine speed for more air flow is recom-mended.

(1) TRAILER TOWING:Consult Trailer Towing section of owners manual.

Do not exceed limits.(2) AIR CONDITIONING; ADD-ON OR AFTER

MARKET:

A maximum cooling package should have beenordered with vehicle if add-on or after market A/C isinstalled. If not, maximum cooling system compo-nents should be installed for model involved permanufacturers specifications.

(3) RECENT SERVICE OR ACCIDENT REPAIR:Determine if any recent service has been per-

formed on vehicle that may effect cooling system.This may be:

Engine adjustments (incorrect timing) Slipping engine accessory drive belt(s) Brakes (possibly dragging) Changed parts. Incorrect water pump, or pump

rotating in wrong direction due to belt not correctlyrouted

Reconditioned radiator or cooling system refill-ing (possibly under filled or air trapped in system).

NOTE: If investigation reveals none of the previousitems as a cause for an engine overheating com-plaint, refer to following Cooling System Diagnosischarts.

These charts are to be used as a quick-referenceonly. Refer to the group text for information.


DIAGNOSIS AND TESTING (Continued)

CAN COOLING SYSTEM 7 - 15

DOOLING SYSTEMCOOLING SYSTEM DIAGNOSIS CHART

CONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READSLOW

1. Has a Diagnostic Trouble Code(DTC) been set indicating a stuckopen thermostat?

1. Refer to Group 25, EmissionSystems for On-Board Diagnosticsand DTC information. Replacethermostat if necessary.

2. Is the temperature sending unitconnected?

2. Check the temperature sensorconnector. Refer to Group 8E.Repair connector if necessary.

3. Is the temperature gaugeoperating OK?

3. Check gauge operation. Refer toGroup 8E. Repair as necessary.

4. Coolant level low in cold ambienttemperatures accompanied withpoor heater performance.

4. Check coolant level in the coolantreserve/overflow tank and theradiator. Inspect system for leaks.Repair leaks as necessary. Refer tothe Coolant section of the manualtext for WARNINGS andCAUTIONS associated withremoving the radiator cap.

5. Improper operation of internalheater doors or heater controls.

5. Inspect heater and repair asnecessary. Refer to Group 24,Heating and Air Conditioning forprocedures.

TEMPERATURE GAUGE READSHIGH OR THE COOLANTWARNING LAMP ILLUMINATES.COOLANT MAY OR MAY NOT BELOST OR LEAKING FROM THECOOLING SYSTEM

1. Trailer is being towed, a steephill is being climbed, vehicle isoperated in slow moving traffic, orengine is being idled with very highambient (outside) temperatures andthe air conditioning is on. Higheraltitudes could aggravate theseconditions.

1. This may be a temporarycondition and repair is notnecessary. Turn off the airconditioning and attempt to drive thevehicle without any of the previousconditions. Observe the temperaturegauge. The gauge should return tothe normal range. If the gauge doesnot return to the normal range,determine the cause for overheatingand repair. Refer to PossibleCauses (2-20).

2. Is the temperature gauge readingcorrectly?

2. Check gauge. Refer to Group 8E.Repair as necessary.

3. Is the temperature warningilluminating unnecessarily?

3. Check warning lamp operation.Refer to Group 8E. Repair asnecessary.

4. Coolant low in coolant reserve/overflow tank and radiator?

4. Check for coolant leaks andrepair as necessary. Refer toTesting Cooling System for Leaks inthis Group.

5. Pressure cap not installed tightly.If cap is loose, boiling point ofcoolant will be lowered. Also refer

5. Tighten cap

IAGNOSIS AND TESTING (Continued)to the following Step 6.


DCONDITION POSSIBLE CAUSES CORRECTION

TEMPERATURE GAUGE READSHIGH OR THE COOLANTWARNING LAMP ILLUMINATES.COOLANT MAY OR MAY NOT BELOST OR LEAKING FROM THECOOLING SYSTEM (cont)

6. Poor seals at the radiator cap. 6. (a) Check condition of cap andcap seals. Refer to Radiator Cap.Replace cap if necessary.

(b) Check condition of radiator fillerneck. If neck is bent or damaged,replace radiator.7. Coolant level low in radiator butnot in coolant reserve/overflowtank. This means the radiator is notdrawing coolant from the coolantreserve/overflow tank as the enginecools

7. (a) Check condition of radiatorcap and cap seals. Refer toRadiator Cap in this Group. Replacecap if necessary.(b) Check condition of radiator fillerneck. If neck is bent or damaged,replace radiator.(c) Check condition of the hose fromthe radiator to the coolant tank. Itshould fit tight at both ends withoutany kinks or tears. Replace hose ifnecessary.(d) Check coolant reserve/overflowtank and tanks hoses for blockage.Repair as necessary.

8. Incorrect coolant concentration 8. Check coolant. Refer to Coolantsection in this Group for correctcoolant/water mixture ratio.

9. Coolant not flowing throughsystem

9. Check for coolant flow at radiatorfiller neck with some coolantremoved, engine warm andthermostat open. Coolant should beobserved flowing through radiator. Ifflow is not observed, determine areaof obstruction and repair asnecessary.

10. Radiator or A/C condenser finsare dirty or clogged.

10. Remove insects and debris.Refer to Radiator Cleaning in thisGroup.

11. Radiator core is corroded orplugged.

11. Have radiator re-cored orreplaced.

12. Aftermarket A/C installedwithout proper radiator.

12. Install proper radiator.

13. Fuel or ignition systemproblems.

13. Refer to Fuel and IgnitionSystem Groups for diagnosis.

14. Dragging brakes. 14. Check and correct asnecessary. Refer to Group 5,Brakes for correct procedures.

15. Bug screen or cardboard isbeing used, reducing airflow.

15. Remove bug screen orcardboard.

16. Thermostat partially orcompletely shut.

16. Check thermostat operation andreplace as necessary. Refer to

IAGNOSIS AND TESTING (Continued)Thermostats in this Group.



TEMPERATURE GAUGE READSHIGH OR THE COOLANTWARNING LAMP ILLUMINATES.COOLANT MAY OR MAY NOT BELOST OR LEAKING FROM THECOOLING SYSTEM (cont)

17. Viscous fan drive not operatingproperly.

17. Check fan drive operation andreplace as necessary. Refer toViscous Fan Drive in this Group.

18. Electric cooling fan notoperating properly (vehiclesequipped with 2.5L engine)

18. Check electric fan operation andrepair as necessary. Refer toElectric Cooling Fan in this Group.

19. Cylinder head gasket leaking. 19. Check for cylinder head gasketleaks. Refer to Cooling System-Testing For Leaks in this Group. Forrepair, refer to Group 9, Engines.

20. Heater core leaking. 20. Check heater core for leaks.Refer to Group 24, Heating and AirConditioning. Repair as necessary.

TEMPERATURE GAUGE READINGIS INCONSISTENT (FLUCTUATES,CYCLES OR IS ERRATIC)

1. On vehicles equipped with anelectric fan, the gauge may cycleup and down. This is due to thecycling of the electric radiator fan.

1. This is a normal condition. Nocorrection is necessary unless thegauge cycles into the red (overheat)zone. Refer to Electric Cooling FanDiagnosis and Testing in this group.

2. During cold weather operation,with the heater blower in the highposition, the gauge reading maydrop slightly.

2. A normal condition. No correctionis necessary.

3. Temperature gauge or enginemounted gauge sensor defective orshorted. Also, corroded or loosewiring in this circuit.

3. Check operation of gauge andrepair if necessary. Refer to Group8E, Instrument Panel and Gauges.

4. Gauge reading rises whenvehicle is brought to a stop afterheavy use (engine still running)

4. A normal condition. No correctionis necessary. Gauge should returnto normal range after vehicle isdriven.

5. Gauge reading high afterre-starting a warmed up (hot)engine.

5. A normal condition. No correctionis necessary. The gauge shouldreturn to normal range after a fewminutes of engine operation.

6. Coolant level low in radiator (airwill build up in the cooling systemcausing the thermostat to openlate).

6. Check and correct coolant leaks.Refer to Cooling System-Testing forleaks in this group.

7. Cylinder head gasket leakingallowing exhaust gas to entercooling system causing athermostat to open late.

7. (a) Check for cylinder headgasket leaks. Refer to CoolingSystem-Testing for Leaks in thisgroup.(b) Check for coolant in the engineoil. Inspect for white steam emittingfrom the exhaust system. Repair asnecessary.

8. Water pump impeller loose on 8. Check water pump and replace

IAGNOSIS AND TESTING (Continued)shaft. as necessary. Refer to water Pumpsin this group.



TEMPERATURE GAUGE READINGIS INCONSISTENT (FLUCTUATES,CYCLES OR IS ERRATIC)

9. Loose accessory drive belt.(water pump slipping)

9. Refer to Accessory Drive Belts inthis group. Check and correct asnecessary.

10. Air leak on the suction side ofthe water pump allows air to buildup in cooling system causingthermostat to open late.

10. Locate leak and repair asnecessary.

PRESSURE CAP IS BLOWINGOFF STEAM AND/OR COOLANTTO COOLANT TANK.TEMPERATURE GAUGE READINGMAY BE ABOVE NORMAL BUTNOT HIGH. COOLANT LEVEL MAYBE HIGH IN COOLANT RESERVE/OVERFLOW TANK

1. Pressure relief valve in radiatorcap is defective.

1. Check condition of radiator capand cap seals. Refer to RadiatorCaps in this group. Replace cap asnecessary.

COOLANT LOSS TO THEGROUND WITHOUT PRESSURECAP BLOWOFF. GAUGE READINGHIGH OR HOT

1. Coolant leaks in radiator, coolingsystem hoses, water pump orengine.

1. Pressure test and repair asnecessary. Refer to CoolingSystem-Testing For Leaks in thisgroup.

DETONATION OR PRE-IGNITION(NOT CAUSED BY IGNITIONSYSTEM). GAUGE MAY OR MAYNOT BE READING HIGH

1. engine overheating. 1. Check reason for overheatingand repair as necessary.

2. Freeze point of coolant notcorrect. Mixture is too rich or toolean.

2. Check coolant concentration.Refer to the Coolant section of thisgroup and adjust ratio as required.

HOSE OR HOSES COLLAPSEWHILE ENGINE IS RUNNING

1. Vacuum created in coolingsystem on engine cool-down is notbeing relieved through coolantreserve/overflow system.

1. (a) Radiator cap relief valvestuck. Refer to Radiator Cap in thisgroup. Replace if necessary

(b) Hose between coolantreserve/overflow tank and radiator iskinked. Repair as necessary.(c) Vent at coolant reserve/overflowtank is plugged. Clean vent andrepair as necessary.(d) Reserve/overflow tank isinternally blocked or plugged. Checkfor blockage and repair asnecessary.

ELECTRIC RADIATOR FAN RUNSALL OF THE TIME

1. Fan relay, powertrain controlmodule (PCM) or coolanttemperature sensor defective.

1. Refer to Electric Cooling FanDiagnosis and Testing. Also refer toGroup 8W, Wiring Diagrams. Repairas necessary.

IAGNOSIS AND TESTING (Continued)



ELECTRIC RADIATOR FAN WILLNOT RUN AT ALL. GAUGEREADING HIGH OR HOT

1. Blown Fuse in Power DistributionCenter (PDC)

1. Determine reason for blown fuseand repair as necessary.

2. Fan relay, powertrain controlmodule (PCM) or coolanttemperature sensor defective.

2. Refer to Electric Cooling FanDiagnosis and Testing. Also refer toGroup 8W, Wiring Diagrams. Repairas necessary.

3. Fan Motor Defective 3. Refer to Electric Cooling FanDiagnosis and Testing. Also refer toGroup 8W, Wiring Diagrams. Repairas necessary.

NOISY VISCOUS FAN/DRIVE 1. Fan blades loose. 1. Replace fan blade assembly.Refer to Cooling System Fans inthis Group

2. Fan blades striking a surroundingobject.

2. Locate point of fan blade contactand repair as necessary.

3. Air obstructions at radiator or airconditioning condenser.

3. Remove obstructions and/orclean debris or insects from radiatoror A/C condenser.

4. Thermal viscous fan drive hasdefective bearing.

4. Replace fan drive. Bearing is notserviceable. Refer to Viscous FanDrive in this group.

5. A certain amount of fan noisemay be evident on modelsequipped with a thermal viscous fandrive. Some of this noise is normal.

5. Refer to Viscous Fan Drive in thisgroup for an explanation of normalfan noise.

INADEQUATE HEATERPERFORMANCE. THERMOSTATFAILED IN OPEN POSITION

1. Has a Diagnostic trouble Code(DTC) been set?

1. Refer to Group 25, Emissions forcorrect procedures and replacethermostat if necessary

2. Coolant level low 2. Refer to Cooling System-TestingFor Leaks in this group.

3. Obstructions in heater hose/fittings

3. Remove heater hoses at bothends and check for obstructions

4. Heater hose kinked 4. Locate kinked area and repair asnecessary

5. Water pump is not pumpingwater to/through the heater core.When the engine is fully warmedup, both heater hoses should behot to the touch. If only one of thehoses is hot, the water pump maynot be operating correctly or theheater core may be plugged.Accessory drive belt may beslipping causing poor water pumpoperation.

5. Refer to Water Pump in thisgroup. If a slipping belt is detected,refer to Accessory Drive Belts in thisgroup. If heater core obstruction isdetected, refer to Group 24, Heatingand Air Conditioning.


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LECTRIC COOLING FANThe powertrain control module (PCM) will set a

iagnostic trouble code (DTC) in memory if it detectsproblem in the electric cooling fan relay or circuit.efer to On-Board Diagnostics in Group 25, Emissionontrol Systems for more information on accessing aTC.The DTC can also be accessed through the DRB

can tool. Refer to the appropriate Powertrain Diag-ostic Procedures manual for diagnostic informationnd operation of the DRB scan tool.

Fig. 24 Electrical Fan AssemblyTypical1 RADIATOR2 ELECTRIC FAN ASSEMBLYCONDITION POSSIBL

STEAM IS COMING FROM THEFRONT OF VEHICLE NEAR THEGRILL AREA WHEN WEATHER ISWET, ENGINE IS WARMED UPAND RUNNING, AND VEHICLE ISSTATIONARY. TEMPERATUREGAUGE IS IN NORMAL RANGE

1. During wet we(snow, ice or rainthe radiator will ethermostat openallows heated wradiator. When thcontacts the hotmay be emitted.in cold weather wairflow to blow it

COOLANT COLOR 1. Coolant coloran indication of aor temperature prely on coolant ccondition of cool

COOLANT LEVEL CHANGES INCOOLANT RESERVE/OVERFLOWTANK. TEMPERATURE GAUGE ISIN NORMAL RANGE

1. Level changesexpected as coofluctuates with eIf the level in thethe FULL and ADoperating tempe

IAGNOSIS AND TESTING (Continued)AUSES CORRECTION

er, moisturendensation) onorate when theis openinginto theoistureator, steam

usually occursno fan ory.

1. Occasional steam emitting fromthis area is normal. No repair isnecessary.

ot necessarilyuate corrosionction. Do notfor determining

1. Refer to Coolant in this group forcoolant concentration information.Adjust coolant mixture asnecessary.

to bevolumee temperature.k was betweenarks at normal

re, the level

1. A normal condition. No repair isnecessary.

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DADIATOR FAN MOTOR INOPERATIVE

quipment Required: DRB Scan Tool Volt/Ohm meter Wiring Diagrams section of this manual

est Procedure:(1) Inspect 10A fuse in junction block and 40Aaxi fuse in PDC (Fig. 25).(2) Remove Cooling Fan Relay from the PDC andake the following checks at the relay connector: Apply 12 volts (using a fused 14-gauge wire) to

ircuit C25 (relay terminal 87). If fan does not comen, check for open in circuit C25 or Z1. If circuits are.k., replace the cooling fan motor. With the ignition key off check for battery volt-

ge at circuit C28 (relay terminal 30). If no batteryoltage present check for open/shorted circuit C28etween the PDC and relay. With the ignition key in the run position check

or battery voltage at circuit F18 (relay terminal 86).f no battery voltage present, check for open/short inircuit F18 between the junction block and the relay. If no problems are detected, install the DRB

refer to the appropriate Powertrain Diagnostic Pro-edures manual for DRB scan tool operating instruc-ions) and start the engine. Clip a 12V test light tohe battery positive terminal and probe circuit C27relay terminal 85). When the engine temperatureeaches 110 C (230 F), or A/C is selected, the testight should light. If not, check circuit C27 for open.

If no problems are detected at this point, replacehe cooling fan relay.

Fig. 25 Power Distribution Center (PDC)

IAGNOSIS AND TESTING (Continued)1 POWER DISTRIBUTION CENTER (PDC)RADIATOR COOLANT FLOW CHECKUse the following procedure to determine if coolant

is flowing through cooling system.(1) Idle engine until operating temperature is

reached. If upper radiator hose is warm to the touch,thermostat is opening and coolant is flowing to radi-ator.

WARNING: HOT, PRESSURIZED COOLANT CANCAUSE INJURY BY SCALDING. USING A RAG TOCOVER RADIATOR PRESSURE CAP, OPEN RADIA-TOR CAP SLOWLY TO FIRST STOP. ALLOW ANYBUILT-UP PRESSURE TO VENT TO THE RESERVE/OVERFLOW TANK. AFTER PRESSURE BUILD-UPHAS BEEN RELEASED, REMOVE CAP FROMFILLER NECK.

(2) Drain a small amount of coolant from radiatoruntil ends of radiator tubes are visible through fillerneck. Idle engine at normal operating temperature. Ifcoolant is flowing past exposed tubes, coolant is cir-culating.

COOLING SYSTEMTESTING FOR LEAKS

ULTRAVIOLET LIGHT METHODA leak detection additive is available through the

parts department that can be added to cooling sys-tem. The additive is highly visible under ultravioletlight (black light). Pour one ounce of additive intocooling system. Place heater control unit in HEATposition. Start and operate engine until radiatorupper hose is warm to touch. Aim the commerciallyavailable black light tool at components to bechecked. If leaks are present, black light will causeadditive to glow a bright green color.

The black light can be used in conjunction with apressure tester to determine if any external leaksexist (Fig. 26).

PRESSURE TESTER METHODThe engine should be at normal operating temper-

ature. Recheck the system cold if cause of coolantloss is not located during the warm engine examina-tion.

WARNING: HOT, PRESSURIZED COOLANT CANCAUSE INJURY BY SCALDING.

Carefully remove radiator pressure cap from fillerneck and check coolant level. Push down on cap todisengage it from stop tabs. Wipe inside of filler neckand examine lower inside sealing seat for nicks,cracks, paint, dirt and solder residue. Inspect radia-

tor-to- reserve/overflow tank hose for internalobstructions. Insert a wire through the hose to besure it is not obstructed.

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DInspect cams on outside of filler neck. If cams areamaged, seating of pressure cap valve and testereal will be affected.Attach pressure tester (7700 or an equivalent) to

adiator filler neck (Fig. 27).

Fig. 26 Leak Detection Using Black LightTypical1 TYPICAL BLACK LIGHT TOOL

Fig. 27 Pressure Testing Cooling SystemTypical1 TYPICAL COOLING SYSTEM PRESSURE TESTER

IAGNOSIS AND TESTING (Continued)Operate tester pump to apply 103.4 kPa (15 psi)pressure to system. If hoses enlarge excessively orbulges while testing, replace as necessary. Observegauge pointer and determine condition of cooling sys-tem according to following criteria:

Holds Steady: If pointer remains steady for twominutes, serious coolant leaks are not present in sys-tem. However, there could be an internal leak thatdoes not appear with normal system test pressure. Ifit is certain that coolant is being lost and leaks can-not be detected, inspect for interior leakage or per-form Internal Leakage Test.

Drops Slowly: Indicates a small leak or seepageis occurring. Examine all connections for seepage orslight leakage with a flashlight. Inspect radiator,hoses, gasket edges and heater. Seal small leak holeswith a Sealer Lubricant (or equivalent). Repair leakholes and inspect system again with pressureapplied.

Drops Quickly: Indicates that serious leakage isoccurring. Examine system for external leakage. Ifleaks are not visible, inspect for internal leakage.Large radiator leak holes should be repaired by areputable radiator repair shop.

INTERNAL LEAKAGE INSPECTIONRemove engine oil pan drain plug and drain a

small amount of engine oil. If coolant is present inthe pan, it will drain first because it is heavier thanoil. An alternative method is to operate engine for ashort period to churn the oil. After this is done,remove engine dipstick and inspect for water glob-ules. Also inspect transmission dipstick for waterglobules and transmission fluid cooler for leakage.

WARNING: WITH RADIATOR PRESSURE TESTERTOOL INSTALLED ON RADIATOR, DO NOT ALLOWPRESSURE TO EXCEED 110 KPA (20 PSI). PRES-SURE WILL BUILD UP QUICKLY IF A COMBUSTIONLEAK IS PRESENT. TO RELEASE PRESSURE,ROCK TESTER FROM SIDE TO SIDE. WHENREMOVING TESTER, DO NOT TURN TESTER MORETHAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.

Operate engine without pressure cap on radiatoruntil thermostat opens. Attach a Pressure Tester tofiller neck. If pressure builds up quickly it indicates acombustion leak exists. This is usually the result of acylinder head gasket leak or crack in engine. Repairas necessary.

If there is not an immediate pressure increase,pump the Pressure Tester. Do this until indicatedpressure is within system range of 110 kPa (16 psi).Fluctuation of gauge pointer indicates compression orc

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spun by hand), replace the fan drive. This spin testmust be performed when the engine is cool.

For the following test, the cooling system must bein good condition. It also will ensure against exces-


DIAGNOSIS AND TESTING (Continued)ombustion leakage into cooling system.Because the vehicle is equipped with a catalytic

onverter, do not remove spark plug cables or shortut cylinders to isolate compression leak.If the needle on dial of pressure tester does not

luctuate, race engine a few times to check for anbnormal amount of coolant or steam. This would bemitting from exhaust pipe. Coolant or steam fromxhaust pipe may indicate a faulty cylinder head gas-et, cracked engine cylinder block or cylinder head.A convenient check for exhaust gas leakage into

ooling system is provided by a commercially avail-ble Block Leak Check tool. Follow manufacturersnstructions when using this product.

OMBUSTION LEAKAGE TESTWITHOUTRESSURE TESTERDO NOT WASTE reusable coolant. If solution is

lean, drain coolant into a clean container for reuse.

ARNING: DO NOT REMOVE CYLINDER BLOCKRAIN PLUGS OR LOOSEN RADIATOR DRAIN-OCK WITH SYSTEM HOT AND UNDER PRESSURE.ERIOUS BURNS FROM COOLANT CAN OCCUR.

Drain sufficient coolant to allow thermostatemoval. Refer to Thermostat Replacement. Discon-ect water pump drive belt.Add coolant to radiator to bring level to within 6.3m (1/4 in) of top of thermostat housing.

AUTION: Avoid overheating. Do not operatengine for an excessive period of time. Open drain-ock immediately after test to eliminate boil over.

Start engine and accelerate rapidly three times, topproximately 3000 rpm while observing coolant. Ifnternal engine combustion gases are leaking intoooling system, bubbles will appear in coolant. If bub-les do not appear, internal combustion gas leakages not present.

ISCOUS FAN DRIVE3.9L/4.7L and 5.9LNGINESIf the fan assembly free-wheels without drag (the

an blades will revolve more than five turns whensively high coolant temperature.

WARNING: BE SURE THAT THERE IS ADEQUATEFAN BLADE CLEARANCE BEFORE DRILLING.

(1) Drill a 3.18-mm (1/8-in) diameter hole in thetop center of the fan shroud between the washer andcoolant reservoirs along the pinch flange. Be carefulnot to pierce the reservoirs..

(2) Obtain a dial thermometer with an 8 inch stem(or equivalent). It should have a range of -18 to105C (0 to 220 F). Insert thermometer through thehole in the shroud. Be sure that there is adequateclearance from the fan blades.

(3) Connect a tachometer and an engine ignitiontiming light (timing light is to be used as a strobelight).

(4) Block the air flow through the radiator. Securea sheet of plastic in front of the radiator (or air con-ditioner condenser). Use tape at the top to secure theplastic and be sure that the air flow is blocked.

(5) Be sure that the air conditioner (if equipped) isturned off.

WARNING: USE EXTREME CAUTION WHEN THEENGINE IS OPERATING. DO NOT STAND IN ADIRECT LINE WITH THE FAN. DO NOT PUT YOURHANDS NEAR THE PULLEYS, BELTS OR FAN. DONOT WEAR LOOSE CLOTHING.

(6) Start the engine and operate at 2400 rpm.Within ten minutes the air temperature (indicated onthe dial thermometer) should be up to 96 C (205 F).Fan drive engagement should have started to occurat between 88 to 96 C (190 to 205 F). Engage-ment is distinguishable by a definite increase in fanflow noise (roaring). The timing light also will indi-cate an increase in the speed of the fan.

(7) When the air temperature reaches 96 C (205F), remove the plastic sheet. Fan drive disengage-ment should have started to occur at between 57 to79 C (135 to 175 F). A definite decrease of fanflow noise (roaring) should be noticed. If not, replacethe defective viscous fan drive unit.

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DACCESSORY DRIVE B

CONDITION POSSIBL

RIB CHUNKING (One or more ribshas separated from belt body)

1. Foreign objecpulley grooves.

2. Installation da

RIB OR BELT WEAR 1. Pulley misalig2. Abrasive envir

3. Rusted pulley4. Sharp or jaggtips5. Belt rubber deCCESSORY DRIVE BELT DIAGNOSIS

ISUAL DIAGNOSISWhen diagnosing serpentine accessory drive belts,

mall cracks that run across the ribbed surface of theelt from rib to rib (Fig. 28), are considered normal.hese are not a reason to replace the belt. However,racks running along a rib (not across) are not nor-al. Any belt with cracks running along a rib must

e replaced (Fig. 28). Also replace the belt if it hasxcessive wear, frayed cords or severe glazing.Refer to the Accessory Drive Belt Diagnosis charts

or further belt diagnosis.

OISE DIAGNOSISNoises generated by the accessory drive belt areost noticeable at idle. Before replacing a belt to

esolve a noise condition, inspect all of the accessoryrive pulleys for alignment, glazing, or excessive endlay.

Fig. 28 Belt Wear Patterns1 NORMAL CRACKS BELT OK2 NOT NORMAL CRACKS REPLACE BELT

IAGNOSIS AND TESTING (Continued)AUSES CORRECTION

bedded in 1. Remove foreign objects frompulley grooves. Replace belt.

e 2. Replace belt

1. Align pulley(s)ent 2. Clean pulley(s). Replace belt if

necessary3. Clean rust from pulley(s)

ulley groove 4. Replace pulley. Inspect belt.

rated 5. Replace belt



BELT SLIPS 1. Belt slipping because ofinsufficient tension

1. Adjust tension (2.5L). Replacetensioner (3.9L/4.7L/5.9L Engines)

2. Belt or pulley exposed tosubstance that has reduced friction(belt dressing, oil, ethylene glycol)

2. Replace belt and clean pulleys

3. Driven component bearing failure(seizure)

3. Replace faulty component orbearing

4. Belt glazed or hardened fromheat and excessive slippage

4. Replace belt.

LONGITUDAL BELT CRACKING 1. Belt has mistracked from pulleygroove

1. Replace belt

2. Pulley groove tip has worn awayrubber to tensile member

2. Replace belt

9GROOVE JUMPING(Belt does not maintain correctposition on pulley)

1. Belt tension either too low or toohigh

1. Adjust belt tension (2.5L).Replace tensioner (3.9L/4.7L/5.9LEngines)

2. Pulley(s) not within designtolerance

2. Replace pulley(s)

3. Foreign object(s) in grooves 3. Remove foreign objects fromgrooves

4. Pulley misalignment 4. Align component5. Belt cordline is broken 5. Replace belt

BELT BROKEN(Note: Identify and correct problembefore new belt is installed)

1. Excessive tension (2.5L) 1. Replace belt and adjust tensionto specification

2. Tensile member damaged duringbelt installation

2. Replace belt

3. Severe misalignment 3. Align pulley(s)4. Bracket, pulley, or bearing failure 4. Replace defective component

and belt

NOISE(Objectionable squeal, squeak, orrumble is heard or felt while drivebelt is in operation)

1. Belt slippage 1. Adjust belt (2.5L). Replacetensioner (3.9L/4.7L/5.9L Engines)

2. Bearing noise 2. Locate and repair3. Belt misalignment 3. Align belt/pulley(s)4. Belt to pulley mismatch 4. Install correct belt5. Driven component inducedvibration

5. Locate defective drivencomponent and repair

6. System resonant frequencyinduced vibration

6. Vary belt tension withinspecifications.


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Dostic Procedures manual for diagnostic informationnd operation of the DRB scan tool.

ADIATOR CAP-TO-FILLER NECK SEALRESSURE RELIEF CHECKThe pressure cap upper gasket (seal) pressure

elief can be tested by removing overflow hose fromadiator filler neck nipple. Attach hose of pressureester tool 7700 (or equivalent) to nipple. It will beecessary to disconnect hose from its adapter foriller neck. Pump air into radiator. The pressure cappper gasket should relieve at 69-124 kPa (10-18 psi)nd hold pressure at a minimum of 55 kPa (8 psi).

ARNING: THE WARNING WORDS DO NOTPEN HOT ON RADIATOR PRESSURE CAP, ARESAFETY PRECAUTION. WHEN HOT, PRESSURE

UILDS UP IN COOLING SYSTEM. TO PREVENT

DETERMINE WHEN PRESSURE HAS BEENRELEASED. WHEN COOLANT AND STEAM STOPBEING PUSHED INTO TANK AND SYSTEM PRES-SURE DROPS, REMOVE RADIATOR CAP COM-PLETELY.

RADIATOR CAPPRESSURE TESTINGRemove cap from radiator. Be sure that sealing

surfaces are clean. Moisten rubber gasket with waterand install cap on pressure tester 7700 or an equiv-alent (Fig. 29).

Operate tester pump to bring pressure to 117 kPa(17 psi) on gauge. If pressure cap fails to hold pres-sure of at least 110 kPa (16 psi) replace cap. Refer tofollowing CAUTION.

The pressure cap may test properly while posi-tioned on tool 7700 (or equivalent). It may not holdCONDITION POSSIBL

TENSION SHEETING FABRICFAILURE(Woven fabric on outside,circumference of belt has cracked orseparated from body of belt)

1. Tension sheetstationary object2. Excessive heafabric to age3. Tension sheetfractured

CORD EDGE FAILURE(Tensile member exposed at edgesof belt or separated from belt body)

1. Excessive ten

2. Belt contactin3. Pulley(s) out o4. Insufficient adtensile member

HERMOSTATAll models are equipped with On-Board Diagnos-

ics for certain cooling system components. Refer ton-Board Diagnostics (OBD) in the Diagnosis section

f this group for additional information. If the pow-rtrain control module (PCM) detects low engine cool-nt temperature, it may record a Diagnostic Troubleode (DTC) in the PCM memory. Do not change a

hermostat for lack of heat as indicated by thenstrument panel gauge or heater performancenless a DTC is present. Refer to the Diagnosis sec-ion of this group for other probable causes. For otherTC numbers, refer to On-Board Diagnostics in theroup 25, Emission Control Systems.The DTC can also be accessed through the DRB

IAGNOSIS AND TESTING (Continued)CALDING OR INJURY, RADIATOR CAP SHOULDOT BE REMOVED WHILE SYSTEM IS HOT AND/ORNDER PRESSURE.AUSES CORRECTION

contacting 1. Correct rubbing condition

using woven 2. Replace belt

splice has 3. Replace belt

1. Adjust belt tension (2.5L).Replace tensioner (3.9L/4.7L/5.9LEngines)

tionary object 2. Replace beltlerance 3. Replace pulleyon betweenrubber matrix

4. Replace belt and adjust tensionto specifications

Do not remove radiator cap at any time except forthe following purposes:

(1) Check and adjust antifreeze freeze point.(2) Refill system with new antifreeze.(3) Conducting service procedures.(4) Checking for vacuum leaks.

WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,WAIT AT LEAST 15 MINUTES BEFORE REMOVINGRADIATOR CAP. WITH A RAG, SQUEEZE RADIATORUPPER HOSE TO CHECK IF SYSTEM IS UNDERPRESSURE. PLACE A RAG OVER CAP AND WITH-OUT PUSHING CAP DOWN, ROTATE IT COUNTER-CLOCKWISE TO FIRST STOP. ALLOW FLUID TOESCAPE THROUGH THE COOLANT RESERVE/pressure or vacuum when installed on radiator. If so,inspect radiator filler neck and caps top gasket for

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Damage. Also inspect for dirt or distortion that mayrevent cap from sealing properly.

AUTION: Radiator pressure testing tools are veryensitive to small air leaks, which will not causeooling system problems. A pressure cap that doesot have a history of coolant loss should not beeplaced just because it leaks slowly when testedith this tool. Add water to tool. Turn tool upsideown and recheck pressure cap to confirm that capeeds replacement.

OOLANTLOW LEVEL AERATIONIf the coolant level in radiator drops below top of

adiator core tubes, air will enter cooling system. On.5L engines, air can gather in the water box con-aining the thermostat.

Low coolant level can cause thermostat pellet to beuspended in air instead of coolant. This will causehermostat to open later, which in turn causes higheroolant temperature. Air trapped in cooling systemlso reduces amount of coolant circulating in heaterore resulting in low heat output.

OOLING SYSTEMDEAERATIONAs the engine operates, any air trapped in cooling

ystem gathers under the radiator cap. The next time

Fig. 29 Pressure Testing Radiator CapTypical1 PRESSURE CAP2 TYPICAL COOLING SYSTEM PRESSURE TESTER

IAGNOSIS AND TESTING (Continued)he engine is operated, thermal expansion of coolantill push any trapped air past radiator cap into the

oolant reserve/overflow tank. Here it escapes to theatmosphere into the tank. When the engine coolsdown the coolant, it will be drawn from the reserve/overflow tank into the radiator to replace anyremoved air.

SERVICE PROCEDURES

COOLANTROUTINE LEVEL CHECK

NOTE: Do not remove radiator cap for routine cool-ant level inspections. The coolant level can bechecked at coolant recovery bottle (Fig. 30).

The coolant reserve/overflow system provides aquick method for determining coolant level withoutremoving radiator pressure cap. With engine not run-ning, open the coolant recovery bottle cap andremove coolant level indicator dipstick to observecoolant level in coolant recovery bottle. The coolantlevel should be between ADD and FULL marks. Ifthe coolant level is at or below the ADD mark, fillthe recovery bottle with a 50/50 mixture of antifreezeand water ONE QUART AT A TIME. Repeat this pro-cedure until the coolant level is at the FULL mark.

COOLANT SERVICEFor cooling system flush and fill maintenance

Fig. 30 Coolant Recovery Bottle Location1 RADIATOR2 WASHER FLUID RESERVOIR3 COOLANT OVERFLOW/RESERVOIR4 FAN SHROUD (UPPER)5 SCREW6 INTERLOCKING PINS7 FAN SHROUD (LOWER)intervals, refer to Group 0, Lubrication and Mainte-nance.

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SOOLANTADDING ADDITIONALDo not remove radiator cap to add coolant to

ystem. When adding coolant to maintain correctevel, do so at coolant reserve/overflow tank. Use a0/50 mixture of ethylene glycol antifreeze containinglugard 340-2 y and low mineral content water.emove radiator cap only for testing or when refill-

ng system after service. Removing cap unnecessarilyan cause loss of coolant and allow air to enter sys-em, which produces corrosion.

OOLANT LEVEL CHECKThe cooling system is closed and designed to main-

ain coolant level to top of radiator.

ARNING: DO NOT OPEN RADIATOR DRAINCOCKITH ENGINE RUNNING OR WHILE ENGINE IS HOTND COOLING SYSTEM IS UNDER PRESSURE.

Remove radiator cap. The coolant level should beo top of radiator. If not, and if coolant level in cool-nt recovery bottle is at ADD mark, check for: An air leak in coolant reserve/overflow tank or

ts hose An air leak in radiator filler neck Leak in pressure cap seal to radiator filler neck

OOLING SYSTEMDRAINING AND FILLING

ARNING: DO NOT REMOVE CYLINDER BLOCKRAIN PLUGS OR LOOSEN RADIATOR DRAIN-OCK WITH SYSTEM HOT AND UNDER PRESSURE.ERIOUS BURNS FROM COOLANT CAN OCCUR.

DO NOT WASTE reusable coolant. If solution islean, drain coolant into a clean container for reuse.

RAINING(1) Remove radiator pressure cap.(2) Loosen radiator petcock.(3) Remove cylinder block drain plugs. Refer to

Fig. 31) (Fig. 32) (Fig. 33).

EFILLING

OTE: This procedure does not apply to the 4.7Lngine.

Clean cooling system prior to refilling. Refer toooling System Cleaning section of this group.(1) Install cylinder block drain plugs. Coat the

hreads with Mopart Thread Sealant with Teflon.(2) Close radiator petcock.(3) Fill cooling system with a 50/50 mixture of

ERVICE PROCEDURES (Continued)ater and antifreeze. Be sure that antifreeze con-ains Alugard 340-2 y as specified in Coolant sectionf this group.(4) Fill coolant reserve/overflow tank to FULLmark on indicator stick.

(5) Start and operate engine until thermostatopens (upper radiator hose warm to touch).

(6) If necessary, add a 50/50 water and antifreezemixture to the coolant reserve/overflow tank. This isdone to maintain coolant level between the FULLand ADD marks. The level in the reserve/overflowtank may drop below the ADD mark after three orfour warm-up and cool-down cycles.

Fig. 31 Cylinder Block Drain Plug2.5L Engine1 EXHAUST MANIFOLD2 CYLINDER BLOCK COOLANT DRAIN PLUG

Fig. 32 Cylinder Block Drain Plug3.9L/5.9LEnginesTypical

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SEFILLING 4.7L ENGINE

AUTION: Failure to follow the procedure outlinedelow, can result in engine overheating conditionsnd sever damage to engine.

(1) Tighten the radiator draincock and the cylinderlock drain plug(s) (if removed).(2) Fill system using a 50/50 mixture of ethylene-

lycol antifreeze and low mineral content water.(3) Fill coolant reservoir to FULL mark.(4) Install radiator cap and reservoir cap.(5) Start engine and run at 3000 RPM for 10 sec-

nds.(6) Shut engine off.(7) Remove radiator cap.(8) Fill radiator to full level.(9) Install the radiator cap.

OOLING SYSTEMCLEANING/REVERSELUSHING

LEANINGDrain cooling system and refill with water. Run

ngine with radiator cap installed until upper radia-or hose is hot. Stop engine and drain water fromystem. If water is dirty, fill system with water, runngine and drain system. Repeat until water drains

Fig. 33 Cylinder Block Drain Plug4.7L EngineTypical

1 CYLINDER BLOCK DRAIN PLUG2 EXHAUST MANIFOLD AND HEAT SHIELD

ERVICE PROCEDURES (Continued)lean.REVERSE FLUSHINGReverse flushing of cooling system is the forcing of

water through the cooling system. This is done usingair pressure in the opposite direction of normal cool-ant flow. It is usually only necessary with very dirtysystems with evidence of partial plugging.

REVERSE FLUSHING RADIATORDisconnect radiator hoses from radiator inlet and

outlet. Attach a section of radiator hose to radiatorbottom outlet fitting and insert flushing gun. Con-nect a water supply hose and air supply hose toflushing gun.

CAUTION: Internal radiator pressure must notexceed 138 kPa (20 psi) as damage to radiator mayresult.

Allow radiator to fill with water. When radiator isfilled, apply air in short blasts. Allow radiator torefill between blasts. Continue this reverse flushinguntil clean water flows out through rear of radiatorcooling tube passages. Have radiator cleaned moreextensively by a radiator repair shop.

REVERSE FLUSHING ENGINEDrain cooling system. Remove thermostat housing

and thermostat. Install thermostat housing. Discon-nect radiator upper hose from radiator and attachflushing gun to hose. Disconnect radiator lower hosefrom water pump and attach a lead-away hose towater pump inlet fitting.

CAUTION: On vehicles equipped with a heaterwater control valve, be sure heater control valve isclosed (heat off). This will prevent coolant flow withscale and other deposits from entering heater core.

Connect water supply hose and air supply hose toflushing gun. Allow engine to fill with water. Whenengine is filled, apply air in short blasts, allowingsystem to fill between air blasts. Continue until cleanwater flows through the lead away hose.

Remove lead away hose, flushing gun, water sup-ply hose and air supply hose. Remove thermostathousing and install thermostat. Install thermostathousing with a replacement gasket. Refer to Thermo-stat Replacement. Connect radiator hoses. Refill cool-ing system with correct antifreeze/water mixture.Refer to Refilling the Cooling System.

CHEMICAL CLEANINGIn some instances, use a radiator cleaner (Mopar Radi-

tor Kleen or equivalent) before flushing. This will softencale and other deposits and aid flushing operation.CAUTION: Follow manufacturers instructions whenusing these products.

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SOOLANT

ESCRIPTION

THYLENE-GLYCOL MIXTURES

AUTION: Richer antifreeze mixtures cannot beeasured with normal field equipment and can

ause problems associated with 100 percent ethyl-ne-glycol.

The required ethylene-glycol (antifreeze) and waterixture depends upon the climate and vehicle oper-

ting conditions. The recommended mixture of 50/50thylene-glycol and water will provide protectiongainst freezing to -37 deg. C (-35 deg. F). The anti-reeze concentration must always be a minimum of4 percent, year-round in all climates. If percentages lower than 44 percent, engine parts may beroded by cavitation, and cooling system com-onents may be severely damaged by corrosion.aximum protection against freezing is providedith a 68 percent antifreeze concentration, whichrevents freezing down to -67.7 deg. C (-90 deg. F). Aigher percentage will freeze at a warmer tempera-ure. Also, a higher percentage of antifreeze canause the engine to overheat because the specificeat of antifreeze is lower than that of water.Use of 100 percent ethylene-glycol will cause for-ation of additive deposits in the system, as the cor-

osion inhibitive additives in ethylene-glycol requirehe presence of water to dissolve. The deposits act asnsulation, causing temperatures to rise to as high as49 deg. C (300) deg. F). This temperature is hotnough to melt plastic and soften solder. Thencreased temperature can result in engine detona-ion. In addition, 100 percent ethylene-glycol freezest 22 deg. C (-8 deg. F ).

ROPYLENE-GLYCOL MIXTURESIts overall effective temperature range is smaller

han that of ethylene-glycol. The freeze point of 50/50ropylene-glycol and water is -32 deg. C (-26 deg. F).deg. C higher than ethylene-glycols freeze point.

he boiling point (protection against summer boil-ver) of propylene-glycol is 125 deg. C (257 deg. F )t 96.5 kPa (14 psi), compared to 128 deg. C (263eg. F) for ethylene-glycol. Use of propylene-glycolan result in boil-over or freeze-up on a cooling sys-em designed for ethylene-glycol. Propylene glycollso has poorer heat transfer characteristics thanthylene glycol. This can increase cylinder head tem-eratures under certain conditions.Propylene-glycol/ethylene-glycol Mixtures can

ERVICE PROCEDURES (Continued)ause the destabilization of various corrosion inhibi-ors, causing damage to the various cooling systemomponents. Also, once ethylene-glycol and propy-lene-glycol based coolants are mixed in the vehicle,conventional methods of determining freeze point willnot be accurate. Both the refractive index and spe-cific gravity differ between ethylene glycol and propy-lene glycol.

OPERATION

ETHYLENE-GLYCOL MIXTURESCoolant flows through the engine block absorbing

the heat from the engine, then flows to the radiatorwhere the cooling fins in the radiator transfers theheat from the coolant to the atmosphere. During coldweather the ethylene-glycol coolant prevents waterpresent in the cooling system from freezing withintemperatures indicated by mixture ratio of coolant towater.

COOLANT SELECTION AND ADDITIVESThe presence of aluminum components in the cool-

ing system requires strict corrosion protection. Main-tain coolant at specified level with a mixture ofethylene-glycol based antifreeze and water. Daimler-Chrysler Corporation recommends Mopar Antifreezeor equivalent. If coolant becomes contaminated orlooses color, drain and flush cooling system and fillwith correctly mixed solution.

CAUTION: Do not use coolant additives that areclaimed to improve engine cooling.

REMOVAL AND INSTALLATION

COOLANT RESERVE/OVERFLOW TANK

NOTE: The coolant reservoir/overflow tank is inte-geral to the upper fan shroud. Refer to Fan Shroudin this section for proper removal/installation proce-dures.

WATER PUMP2.5L ENGINE

REMOVAL

CAUTION: The 2.5L engine has a reverse (counter-clockwise) rotating water pump. The letter R isstamped into the back of the water pump impeller(Fig. 34) to identify. Engines from previous modelyears, depending upon application, may beequipped with a forward (clockwise) rotating waterpump. Installation of the wrong water pump willcause engine over heating.

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R )The water pump can be removed without discharg-ng the air conditioning system (if equipped).

The water pump impeller is pressed on the rear ofhe pump shaft and bearing assembly. The waterump is serviced only as a complete assembly.

ARNING: DO NOT REMOVE THE BLOCK DRAINLUG(S) OR LOOSEN RADIATOR DRAINCOCKITH THE SYSTEM HOT AND UNDER PRESSURE.ERIOUS BURNS FROM COOLANT CAN OCCUR.

DO NOT WASTE reusable coolant. If the solutions clean, drain coolant into a clean container foreuse.(1) Disconnect the battery negative cable.(2) Drain the cooling system.(3) Remove the accessory drive belt.(4) Remove power steering pump (Fig. 35), refer toroup 19 Steering for the correct procedure.

ARNING: CONSTANT TENSION HOSE CLAMPSRE USED ON MOST COOLING SYSTEM HOSES.HEN REMOVING OR INSTALLING, USE ONLY

OOLS DESIGNED FOR SERVICING THIS TYPE OFLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER094) (Fig. 36) SNAP-ON CLAMP TOOL (NUMBERPC-20) MAY BE USED FOR LARGER CLAMPS.LWAYS WEAR SAFETY GLASSES WHEN SERVIC-

NG CONSTANT TENSION CLAMPS.

Fig. 34 Reverse Rotating Water PumpTypical1 R STAMPED INTO IMPELLER

EMOVAL AND INSTALLATION (ContinuedAUTION: A number or letter is stamped into theongue of constant tension clamps (Fig. 37). Ifreplacement is necessary, use only an originalequipment clamp with matching number or letter.

(5) Remove lower radiator hose from water pump.Remove heater hose from water pump fitting.

(6) Remove the four pump mounting bolts (Fig. 38)and remove pump from vehicle. Discard old gasket.Note that one of the four bolts is longer than theother bolts.

(7) If pump is to be replaced, the heater hose fit-ting must be removed and transferred to the newpump. Note position of fitting before removal.

Fig. 35 Power Steering Pump Attachment1 INTAKE MANIFOLD2 PUMP ASSEMBLY 2.5L3 PUMP BRACKET

Fig. 36 Hose Clamp ToolTypical1 HOSE CLAMP TOOL 60942 HOSE CLAMPINSTALLATION(1) If pump is being replaced, install the heater

hose fitting to the pump. Use a sealant on the fitting

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R )uch as Mopary Thread Sealant With Teflon. Refero the directions on the package.

(2) Clean the gasket mating surfaces. If the origi-al pump is used, remove any deposits or other for-ign material. Inspect the cylinder block and waterump mating surfaces for erosion or damage fromavitation.(3) Install the gasket and water pump. The sili-

one bead on the gasket should be facing the waterump. Also, the gasket is installed dry. Tightenounting bolts to 30 Nm (22 ft. lbs.) torque. Rotate

he shaft by hand to be sure it turns freely.(4) Connect the radiator and heater hoses to theater pump.(5) Position water pump pulley to water pump

ub.(6) Install power steering pump.

AUTION: When installing the serpentine acces-ory drive belt, the belt MUST be routed correctly. Ifot, the engine may overheat due to the waterump rotating in the wrong direction. Refer to theelt Removal and Installation in this group forppropriate belt routing. You may also refer to theelt Routing Label in the vehicle engine compart-ent.

(7) Adjust accessory drive belt, refer to Accessoryrive Belt removal and installation in this group.(8) Fill cooling system with coolant and check for

eaks. Refer to Refilling Cooling System in thisroup.(9) Connect battery battery negative cable.

Fig. 37 Clamp Number/Letter Location1 CONSTANT TENSION HOSE CLAMP2 CLAMP NUMBER/LETTER LOCATION3 HOSE

EMOVAL AND INSTALLATION (Continued(10) Start and warm the engine. Check for leaks.WATER PUMP3.9L/5.9L ENGINES

REMOVALThe water pump can be removed and installed

without discharging the air conditioning system (ifequipped).

(1) Disconnect battery negative cable.(2) Drain cooling system. Refer to Cooling Sys-

temDraining and Filling in this group.(3) Do not waste reusable coolant. If solution is

clean, drain coolant into a clean container for reuse.

Fig. 38 Water Pump Remove/InstallTypical1 (4) PULLEY MOUNTING STUDS2 HEATER HOSE FITTING3 UPPER VENT HOLE4 PUMP GASKET5 WATER PUMP6 LOWER VENT HOLE7 LONG BOLT8 BOLTS (3) SHORT

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R )ARNING: CONSTANT TENSION HOSE CLAMPSRE USED ON MOST COOLING SYSTEM HOSES.HEN REMOVING OR INSTALLING, USE ONLY

OOLS DESIGNED FOR SERVICING THIS TYPE OFLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER094) (Fig. 36). SNAP-ON CLAMP TOOL (NUMBERPC-20) MAY BE USED FOR LARGER CLAMPS.LWAYS WEAR SAFETY GLASSES WHEN SERVIC-

NG CONSTANT TENSION CLAMPS.

AUTION: A number or letter is stamped into theongue of constant tension clamps (Fig. 37). Ifeplacement is necessary, use only an originalquipment clamp with matching number or letter.

(4) Remove upper radiator hose clamp and hose atadiator.(5) The thermal viscous fan drive is attached

threaded) to the water pump hub shaft (Fig. 40).emove fan/viscous fan drive assembly from waterump by turning mounting nut counterclockwise asiewed from front. Threads on viscous fan drive areIGHT HAND. A Snap-On 36 MM Fan Wrench

number SP346 from Snap-On Cummins Diesel Toolet number 2017DSP) and Special Tool 6958 Span-er Wrench with Adapter Pins 8346 can be used.lace Special Tool 6958 Spanner Wrench onto theater pump pulley with Adapter Pins 8346 inserted

nto the holes on the pulley (Fig. 39) to prevent pul-ey from rotating. Do not attempt to remove fan/vis-ous fan drive assembly from vehicle at this time.(6) If water pump is being replaced, do not unbolt

an blade assembly (Fig. 40) from thermal viscousan drive.

(7) Remove fan shroud attaching hardware (twoolts at bottom-two clips at top).(8) Remove fan shroud and fan blade/viscous fan

rive assembly from vehicle as a complete unit.(9) After removing fan blade/viscous fan drive

ssembly, do not place thermal viscous fan drive inorizontal position. If stored horizontally, siliconeluid in viscous fan drive could drain into its bearingssembly and contaminate lubricant.(10) Remove accessory drive belt as follows: The

rive belt is equipped with a spring loaded automaticensioner (Fig. 41). Relax tension from belt by rotat-ng tensioner clockwise (as viewed from front) (Fig.1). When all belt tension has been relaxed, removeccessory drive belt.

EMOVAL AND INSTALLATION (ContinuedFig. 40 Fan Blade and Viscous Fan Drive3.9L/5.9LEngines

1 WATER PUMP BYPASS HOSE2 FAN BLADE ASSEMBLY3 VISCOUS FAN DRIVE4 WATER PUMP AND PULLEYFig. 39 Viscous Fan Drive Removal / Installation1 SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER

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R )(11) Remove lower radiator hose clamp and removeower hose at water pump.

(12) Remove heater hose clamp and heater hoserom heater hose coolant return tube.

(13) Loosen heater hose coolant return tubeounting bolt (Fig. 42) and remove tube from water

ump. Discard the old tube O-ring.(14) Remove seven water pump mounting bolts.(15) Loosen clamp at water pump end of bypass

ose (Fig. 40). Slip bypass hose from water pumphile removing pump from vehicle. Discard old gas-et.

AUTION: Do not pry water pump at timing chainase/cover. The machined surfaces may be dam-ged resulting in leaks.

NSTALLATION(1) Clean gasket mating surfaces.(2) Using a new gasket, install water pump to

ngine as follows: Guide water pump nipple intoypass hose as pump is being installed. Install waterump bolts. Tighten water pump mounting bolts to0 Nm (30 ft. lbs.) torque.

Fig. 41 Automatic Belt Tensioner Assembly3.9L/5.9L Engines

1 IDLER PULLEY2 TENSIONER3 FAN BLADE

EMOVAL AND INSTALLATION (Continued(3) Position bypass hose clamp to bypass hose.(4) Spin water pump to be sure that pump impel-

ler does not rub against timing chain case/cover.(5) Install a new O-ring to the heater hose coolant

return tube (Fig. 42). Coat the new O-ring with anti-freeze before installation.

(6) Install coolant return tube and its mountingbolt to engine (Fig. 42). Be sure the slot in tubebracket is bottomed to mounting bolt. This will prop-erly position return tube.

(7) Connect radiator lower hose to water pump.(8) Connect heater hose and hose clamp to coolant

return tube.(9) Relax tension from belt tensioner (Fig. 41).

Install accessory drive belt.

CAUTION: When installing the serpentine acces-sory drive belt, the belt must be routed correctly. Ifnot, engine may overheat due to water pump rotat-ing in wrong direction. Refer to (Fig. 43) for correctbelt routing. The correct belt with correct lengthmust be used.

Fig. 42 Coolant Return Tube3.9L/5.9L EnginesTypical

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R )(10) Position fan shroud and fan blade/viscous fanrive assembly to vehicle as a complete unit.(11) Install fan shroud.(12) Install fan blade/viscous fan drive assembly toater pump shaft.(13) Fill cooling system. Refer to Cooling Systemraining and Refilling in this group.(14) Connect battery negative cable.(15) Start and warm the engine. Check for leaks.

ATER PUMP 4.7L ENGINESThe water pump on 4.7L engines is bolted directly

o the engine timing chain case/cover.A gasket is used as a seal between the water pump

nd timing chain case/cover.If water pump is replaced because of bearing/shaft

amage, or leaking shaft seal, the mechanical coolingan assembly should also be inspected. Inspect foratigue cracks, loose blades, or loose rivets that couldave resulted from excessive vibration. Replace fan ifny of these conditions are found. Also check condi-ion of the thermal viscous fan drive. Refer to Viscous

Fig. 43 Belt Routing3.9L/5.9L Engines1 IDLER PULLEY2 GEN.3 A/C COMP.4 IF W/OUT A/C5 PWR. STRG. PUMP6 WAT. PUMP7 CRANK PULLEY8 AUTOMATIC TENSIONER

EMOVAL AND INSTALLATION (Continuedan Drive in this group.The water pump can be removed without discharg-

ng the air conditioning system (if equipped).

tiwREMOVAL(1) Disconnect negative battery cable from battery.(2) Drain cooling system. Refer to Draining Cool-

ing System in this group.Do not waste reusable coolant. If solution is clean,

drain coolant into a clean container for reuse.(3) The thermal viscous fan drive is attached

(threaded) to the water pump hub shaft. Remove fan/viscous fan drive assembly from water pump by turn-ing mounting nut counterclockwise as viewed fromfront. Threads on viscous fan drive are RIGHT

AND. Using special tool spanner wrench 6958 withdapter pins 8346 and a suitable fan wrench loosenhe fan drive (Fig. 44). Do not attempt to remove fan/iscous fan drive assembly from vehicle at this time.

ARNING: CONSTANT TENSION HOSE CLAMPSRE USED ON MOST COOLING SYSTEM HOSES.HEN REMOVING OR INSTALLING, USE ONLY

OOLS DESIGNED FOR SERVICING THIS TYPE OFLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)AY BE USED FOR LARGER CLAMPS. ALWAYSEAR SAFETY GLASSES WHEN SERVICING CON-TANT TENSION CLAMPS.

AUTION: A number or letter is stamped into the

Fig. 44 Viscous Fan and Fan Drive 4.7L1 SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER

PINS 83462 FANongue of constant tension clamps. If replacements necessary, use only an original equipment clampith matching number or letter.

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R )(4) If water pump is being replaced, do not unboltan blade assembly from thermal viscous fan drive.

(5) Remove two fan shroud-to-radiator screws (Fig.5). Disconnect the coolant overflow hose, windshieldasher fluid hose and washer pump electrical con-ector.

(6) Remove upper fan shroud and fan blade/viscousan drive assembly from vehicle.

(7) After removing fan blade/viscous fan drivessembly, do not place thermal viscous fan drive inorizontal position. If stored horizontally, siliconeluid in viscous fan drive could drain into its bearingssembly and contaminate lubricant.(8) Remove accessory drive belt as follows: The

rive belt is equipped with a spring loaded automaticelt tensioner. Relax tension from belt by rotatingensioner clockwise (as viewed from front) (Fig. 46).

hen all belt tension has been relaxed, removeccessory drive belt.(9) Remove lower radiator hose clamp and remove

ower hose at water pump.(10) Remove seven water pump mounting bolts

nd one stud bolt.

Fig. 45 Upper Fan Shroud, Coolant reservoir andWasher Fluid Reservoir

1 RADIATOR2 WASHER FLUID RESERVOIR3 COOLANT OVERFLOW/RESERVOIR4 FAN SHROUD

(UPPER)5 SCREW6 INTERLOCKING PINS7 FAN SHROUD

(LOWER)

EMOVAL AND INSTALLATION (ContinuedCAUTION: Do not pry water pump at timing chaincase/cover. The machined surfaces may be dam-aged resulting in leaks.

(11) Remove water pump and gasket. Discard gas-ket.

INSTALLATION(1) Clean gasket mating surfaces.(2) Using a new gasket, position water pump and

install mounting bolts as shown. (Fig. 47). Tightenwater pump mounting bolts to 54 Nm (40 ft. lbs.)torque.

00AN_7

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