Optimizing Oil Change Intervals

7/28/2019 Optimizing Oil Change Intervals

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Optimizing Oil Change IntervalsFor All Diesel Engines Except On-Highway Truck Engines

MAINTENANCE SERVICES


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MaximizeEngineLife

Getting the Most from Your Oil and Your Engine

Maintaining your engine oil is a very

important factor in maximizing the

productive life of your Cat engines. It

begins when you demand the higher

standard of protection available from Cat

engine oil and filters. And it continues as you work with us

to optimize the effective life of the oil. Cat

engines have recommended oil change

intervals determined through extensive testing

and historical data. However, these intervals

cannot take into account your specific operating conditions and

other factors that may necessitate a different oil change schedule.

Our SOSSM fluid analysis program helps you understand

the factors affecting your engine oil, so you can better manage

the life cycles of your engines and reduce costs.


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Consider these factorswhen evaluating youroil performanceTo optimize oil change intervals, it isimportant to det ermine how w ell your oil

will hold up under specific conditions. To dothis, all factors affecting oil condition must

be controlled and stabilized during evalua-tion. Everything that could have an impact onoil condition must be held constant during

the evaluation period so you can monitorthe effects of application and load on

the oil.

ApplicationThe same load should beapplied (relatively the same amount of

fuel consumed per hour) in the sameoperati ng and climatic conditions.

Oil FiltersThe same filters (preferably Cat

filters) should be used for all engines in thetest group, and they should all be changed

at the same interval. Use Cat f ilters t oguarantee the highest quality filteravailable.

Air FiltersChange only as required bythe air restriction indicator. Again, use Catair filters to assure the highest quality and

longest l i fe.

Cooling System M aintenanceCoolingsystem problems contribute to more than

50% of all premat ure engine failures andproblem s. Initial ly, submit coolant samplesfor Level 2 SOS Coolant Analysis toassure the cooling systems on all test unitsare optimal. Assure t hat radiators areclean external ly and int ernally. Propercoolant and conditioner levels should bemaintained. Over-heating o r over-coolingcan increase oil oxidation and/or sulfurproduct f ormation. Use SOS Level 1Coolant Analysis at each oil change tomake sure your cooling system andcoolant are up to par.

Operating PracticesOperating techniquesimpact how an oil responds and holds up to

an application. Excessive lugging, excessiveidling and full throttle on/off will all affect

sooting and oxidation of oil.

Optimally Tuned EnginesKeep enginesrunning according to specifications. Check

boost, fuel sett ings, air/fuel ratio controland transmission shift points. Poorly tuned

engines can lead to malfunctions oradversely affect operating temperatures,fuel consumption, or other parameters.

External ContaminationTake a baselineoil sample from each engine in the testgroup at every oil change to m ake sure

no external contaminants are int roduced

w ith new oi l .

Selection of Test EnginesInclude

engines w ith relatively low total operatinghours and those never having grossly

extended oil change intervals. Engines withhigher hours have different wear and oil

consumption rates t han new er engines.Engines that have had grossly extendedoil change intervals or t hat have used

lower quality oils may already haveirreversible oil-related problems at the

start of the evaluation, i.e. lacquering,ring st icking and carbon build-up.

Provide completeSOS information

Be sure to correctly and completely

fill out the SOS sample bottle card

or label. This information is critical

to assure accurate data from the lab

tests and the interpretation of the

data. In particular, it is essential to

include the total hours (or odometer

units) on the engine, the total

hours/units on the oil, and the

quantity of make-up oil added

since the last oil change.


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MonitorEngineWear

Understanding the Causes of Engine Wear

SOS OIL ANALYSISTEST RESULTS

INTERNAL CONTAMINATION

Normal Wear (Rings/Liners, etc.)

Sacrificial Surfaces (Bearings)

Assembly Fit/Torque

Break-in Wear (New/Rebuild)

Manufacturing Debris (New/Rebuild)

Mating Surfaces Fit/Finish

Parts Defects

Competitive Parts Use

Climate/Terrain

Severe/Improper Operation

Excessive Idling/Lugging

High Altitude

High Operating Temps.

High Humidity

Cold Operating Temps.

Water (Coolant/Other)

Glycol (Coolant)

Fuel

Dirt

Oil Transfer from Another Compartment

EXTERNAL CONTAMINATION

MAINTENANCE

CONTAMINANTS

Wrong Oil Used

Plugged Air Filter

Improper Fuel Setting

Extended Oil ChangePoor Cooling System Maintenance

Fuel Quality

APPLICATION

ENGINE LIFE CYCLE AFFECTED

Metallic Element(s)

Metallic Element(s) Increase

Viscosity

TBN

Soot

OIL CONDITION

OxidationNitration

Sulfation

**

*

*

Positive Water

Positive Glycol

Fuel Dilution

Silicon/Aluminum

Viscosity*

* TBN and Viscosity are optional tests within the SOS oil analysis program.

* * Nitration is seldom a problem for diesel engines, but can be significant for natural gas engines.


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Variable factors affectinglubrication and wearThere are a number of factors thatoperators and maintenance engineers can

control to affect engine wear and costs. Ageneral indication of how well a lubricant

is performing during an oil change intervalis the amount of w ear metals generated

during that time period. The rate andamount of wear occurring in an enginedepends on four categories of causes (see

chart, facing page). This chart provides avery simplified explanation of the causes

of oil degradation and wear metalgeneration for diesel engines. The items

show n in the SOS Oil A nalysis TestResults column are those for whichCaterpillar engineers have selected tests.

1. M aintenanceErrors and om issions inroutine preventive maintenance practicesw il l affect oil condit ion, result ing in

increased engine wear.

2. ApplicationEnvironmental andoperational f actors that contribute

directly to increased w ear and/ oroil condition degradation.

3. External ContaminationFuel, water,

glycol or anything else getting into theengine lubricating system from the outside,

accelerating w ear.

4. Internal ContaminationThe causes ofexcessive internal contamination are usually

misalignment of mating parts, improperlytorqued bolts and nuts or defective parts.

Internal contamination becomes a grindingagent which adds to internal debrisproduced by parts wearing together.

At some oil change interval, there is a reasonable balance.

Decreased Oil and Filter CostsDecreased Maintenance/Labor Costs

Decreased DisposalIncreased Availability and Productivity

ENGINE OILCHANGE HOURS

Decreased Engine LifeIncreased Repair Downtime

Increased Repair CostsDecreased Availability and Productivity

REWARDS RISKS

If SOS oil analysis indicates a problem in

any of its tests, give consideration to eachpossible cause. Correct or alleviate thecauses if possible. Be alert for changes

in any of the M aintenance or Applicationfactors which might lead to a problem.

Doing this will help control and stabilizeall the factors impa cting oil conditions

during the evaluation period.

Monitor oil consumptionNot show n on the chart (previous page)

is the addit ion of make-up oil. If make-up oil is added, all the oil analysis

results wi l l be affected. It is veryimportant to keep accurate records

and report on each oil sample labelthe quantity of oil added.

The oil change intervalbalanceAs with most business decisions,

establishing an engine oil changeinterval beyond the manufacturersrecommendation has both risks and

rew ards. Perhaps the biggest potentialreward is increased availabil ity due

to less maintenance downtime. But thisincrease can be quickly eroded if reduced

engine life causes premature w ear andrepair downtime. Extending oil change

intervals without a carefully plannedand executed program is gambling withthe l ife of your engines and your

cost of production.


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Four types of oil samplesThere are four categories of oil samplesinvolved in evaluating an oil change

interval:

1. Samples of New OilA sample of t he new oil is needed asa test reference to the used oil. The new

oil sample must be the exact same oilas the used oil being tested. Any tim e

a new shipment of oil is received, asample of that oil must be submitted

as the reference.6

ExtendOilChangeIntervals

Determining Optimal Oil Change Intervals

SAMPLE PERIODS FOR ESTABLISHING OPTIMAL OIL CHANGE INTERVALS(after two or t hree oil changes at the standard interval)

NEW OIL SAM PLE

BASELINE SAM PLE75 HOURS

150 HOURS

250 HOURS

300 HOURS

350 HOURS

ETC.

(recommended change interval)

(first extended interval)

(second extended interval)

(samples at shortened intervals)

For engineswith 250-hourrecommended oilchange intervals:

4.Samples at Oil ChangeTest results from the samples taken at thetime of each oil change will indicate thefinal levels of oil degradation and w ear

accumulation. These results, along withthe shortened interval sample results, will

be evaluated to establish the optimal oilchange interval for your engine. Once the

optimal interval has been established,submit a sample at each oil change.

Engine coolant samplesBecause many engine problems areinfluenced by the cooling system, coolant

samples should also be submitted. Level 2Coolant Analysis should be performed at

the beginning of the project and Level 1tests at each oil change thereafter duringthe project.

We suggest you proceed beyond themanufacturers recommended oil changeperiod cautiously in incremental steps of

50 hours. First, determine that wear ratesand oil condit ion are satisfactory at the

250 interval. Then, extend from the 250-hour recommended period to 300 hours.Stay with a 300-hour period for several

changes and closely monitor the SOSresults w ith samples taken as shown

on the chart below.

2.Baseline SamplesAfter changing the oil and filter, runthe engine until it reaches operatingtemperature (about 15 m inute s) and t ake

a sample. This determines wear metalcarryover from a ny oil left in the pan from

the previous interval. It also reveals if anyexternal contaminants were introduced

through the oil fill process. During theevaluation period, take a baselinesample aft er every oil change.

3.Samples at Shortened Intervals

Taking samples at less than the recom-mended oil change interval is essential

to monitoring the oil degradation process.This will allow you to determine a trend

line for wear accumulation and anyexternal contamination entry. You

must establish these rates for therecommended oil change intervalbefore you begin an extended interval

evaluation (see chart).

We suggest that engines with a 500-

hour recommended oil change interval

should not be extended beyond that

point. In some applications, it has

been necessary to reduce the interval

from 500 hours to a more frequent

schedule.

Proceed w ith caution


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Work with our expertsWe will work with you to optimize the oil

change periods for your Cat engines. Keepin mind, however, that the process of

determining new oil change intervals isnot simple. It requires that you work closely

with our staff over a period of severalmonths. Once new intervals are establish-ed, it w ill be more important than ever

to carefully monitor oil performance andengine wear using SOS analysis for

both oil and coolant to make surethere arent any problems.

Use Cat FiltersIf you w ant to evaluate

the possibility of oil change intervals ot herthan t hose published b y Caterpillar for

your engines, you must protect your enginewith high-quality products. Cat filters

are designed to do the job beyond thepublished oil change periods. This extraprotection assures you can maintain the

same filter change periods as your newlyestablished oil change periods. Although

there may be a small difference in price,it is well worth it to guarantee that yourengines are protected.

And Use Cat Diesel Engine Oil If notCat DEO, use a premium quality API

CG-4 or CH-4 oil. Diesel engine oils thatmeet API specifications CG-4 and CH-4

contain the best addit ive package andbase oil stock to help you achieve longeroil use and maximum engine l ife. But

even w ith those A PI categories therecan be w ide variations in performance

(w hich is reflected by the range of pricesfor CG-4 and CH-4 oil). Oil is viewed bysome as a commodity, but as a rule, you

get w hat you pay for a higher qual i tyadd pack and base stock costs more

than low er quality alternatives. Toensure you get the best oil for your

money use Cat oil in your engines.*

* Caterpillar now offers a full synthetic diesel

engine oil. This premium-priced lubricant is

designed to achieve longer oil change intervals.


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PEDP7035 For more information, see us today Printed in U.S.A.or visit our W eb site at w w w.CAT.com 1998 Caterpi l lar

Cat Fluids:Formulated to provide

higher standards in performance

and life.

Cat Fluid Filters:System engineered

for optimal performance andprotection.

SOS Analysis:The ultimate

approach for assuring maximum

productivity and achieving full

design life for your equipment.

Maintenance Software:Trend

Analysis Module (TAM) for SOS

results, Maintenance Control System(MCS) for scheduling and record

keeping and Preventive Maintenance

Planner (PMP) for comprehensive

maintenance checklists.

Extend equipment l i few i th qual it y Catmain tenance pr oducts .

Optimizing Oil Change Intervals

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