Navistar ProStar+ User Manual

Operation
AirCompressorCycling
Theenginescanbeequippedwithoneoftwodifferenttypesof
aircompressorandmayhaveoneortwocylinders.
•HeadUnloadedAirCompressor:Thissinglecylinder,
constantlyengagedaircompressorworksinconjunction
withtheairgovernorandairdryertopumpcompressed
airtotheairdryerandairtanks.Whenadditional
compressedairisnotneeded,airisshutofffromthe
aircompressordischargelineandconnedtotheair
compressorcylinderanditshead.
•ClutchedAirCompressor:Thishigh-capacity,two
cylinder,aircompressorisperiodicallyengagedby
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.
CoolingSystem
WARNING
Topreventpropertydamage,personalinjury,
and/ordeath,useonlythefollowingprocedure
toremovethepressurecapfromtheradiator
orexpansiontank.Allowtheenginetocool
rst.Wrapathick,heavyclotharoundthecap.
Unscrewthecapslowlytoallowpressureto
releasefromunderthecap.Afterthepressure
hasbeenreleased,thepressurecapmaybe
removed.
WARNING
Topreventpropertydamage,personalinjury,
and/ordeath,exercisegreatcarewhenworking
onvehicleswithrunningenginesthatare
equippedwithanautomaticfanclutch.The
fanengageswhenenginecoolantreachesa
predeterminedtemperatureortherefrigerant
pressure(ifequippedwithairconditioning)
reachesapredeterminedsetting.Thefanwill
startwithnoadvancewarning.
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Navistar ProStar+ Specifications

General

Brand	Navistar
Model	ProStar+
Category	Trucks
Language	English