Navistar International LT Series - Self Diagnostics; Air Compressor Cycling; Engine Oil

Operation
SelfDiagnostics
Allwarninglampsarelocatedontheelectronicgaugecluster.
WhentheignitionswitchisturnedON,thewarninglamps
areilluminatedandremainonwhiletheECMrunsnormal
start-uptests,thengoesOFF.Ifawarninglampstaysonor
comesonwhileoperatingthevehicle,itisanindicationthatthe
vehicleneedsservice.Whenthewarninglampisilluminated,
aDiagnosticTroubleCode(DTC)willbegenerated.T akethe
vehicletoaservicecenterassoonaspossibleassomeoptional
featuresand/orenginepowermaybelostwhiletheindicator
islit.
AirCompressorCycling
Theenginescanbeequippedwithoneoftwodifferenttypesof
aircompressorandmayhaveoneortwocylinders.
•HeadUnloadedAirCompressor:Thissingle-cylinder,
constantlyengagedaircompressorworksinconjunction
withtheairgovernorandairdryertopumpcompressed
airtotheairdryerandairtanks.Whenadditional
compressedairisnotneeded,airisshutofffromthe
aircompressordischargelineandconnedtotheair
compressorcylinderanditshead.
•ClutchedAirCompressor:Thishigh-capacity,
two-cylinderaircompressorisperiodicallyengagedby
usinganON/OFFclutch.Itworksinconjunctionwith
airgovernorandairdryertopumpairtotheairdryer
andairtanks.Whenadditionalcompressedairisnot
needed,theclutchisdisengaged,compressorspeed
goestozero,andallairpumpingceases.Thissystem
providesrelativelylowcylindertemperaturesandsound
versusothercompressorsduringtheunloadedcycle.Itis
usedtopromotemaximumfueleconomybyeliminating
pumpingenergylossduringtheunloadedcycle.
Asthecompressorreachesapproximately130psi(896kPa),
theairgovernorwill,throughvariousmethods,stoptheair
compressorfrompumpingpressurizedairtotheairsystem.
Whentheairpressurereachesapproximately110psi(758
kPa),thegovernorsignalstheaircompressortoresume
pumpingpressurizedairtotheairsystem.Duringnormal
engineoperation,thiscyclewillbeevidentbytheuctuationof
theprimaryairtankpressuregauge.
EngineOil
KeepoillevelbetweentheADDandFULLmarks.Neveroperate
anenginewithoillevelbelowtheADDmark.
Toobtainanaccurateengineoillevelreading,thevehiclemust
beparkedonalevelsurfacewiththeengineoffforatleast15
minutesbeforecheckingtheoillevel.Thiswillensuretheoil
islevelintheoilpanandthecirculatedoilhashadachanceto
returntothepan.Itisnotnecessaryfortheoiltobehottoobtain
anaccuratereading.
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