Navistar MaxxForce 7 - Operation; Suggested Warm-Up Time; Idle Speed; Extended Idling Periods

SECTION4–ENGINEOPERATION
Operation
SUGGESTEDWARM-UPTIME
NOTE:Thewarmupperiodallowslubricatingoiltoestablisha
lmbetweenmovingparts.Keeptheenginelowerthan1800
rpmsandbelowhalfthrottlefortherst5minutes.
Coldambientenginewarm-uptimecanbereducedbyoperating
theengineunderloadatreducedenginespeed.Beginnormal
operationwhenenginesystemsreachoperatingtemperature.
TheColdAmbientProtection(CAP)systemaidsinengine
warm-upandmaintainsengineheatduringextendedidling
periods.ForfurtherinformationseeExtendedIdlingPeriods
(page54).
IDLESPEED
WARNING:Topreventpersonalinjuryordeath,
provideventilationwhenoperatinganengineinaclosed
area.Inhalationofexhaustgascanbefatal.
LowidlespeedfortheMaxxForce
®
7DieselEnginesis700
rpm(nonadjustable).Iftheenginecoolanttemperatureisbelow
167°F(75°C)andCAPisenabled,theEngineControlModule
(ECM)adjuststhelowidlespeedfrom700rpmtoamaximumof
1400rpm.Highidlespeed(2950rpm)isanonadjustablefactory
setting.
EXTENDEDIDLINGPERIODS
CAUTION:T opreventenginedamage,donotextendlowidle
periods.
Extendedidlingperiodsshouldbeavoided.Dieselengine
efciencyisimprovedwhenthecylindertemperatureremains
high.Lowtemperatureincylindersmaycausethefollowing:
•Unburnedfuelmayseepfromexhaustmanifoldgasketsand
vehicleexhaustsystemconnections.Thisseepagehasthe
darkcoloredappearanceoflubricatingoil.
•Incompletecombustionandunburnedfuelwillwash
lubricatingoilfromcylindersleeves.Unburnedfuelwillbe
carriedintothelubricatingoil,dilutetheoil,andchangeoil
viscosity.
•Carbonwillformoninternalcomponentsofturbocharger
andExhaustGasRecirculation(EGR),reducingengine
efciency.
•CarbonwillcloganddamagetheDieselParticulateFilter
(DPF).
Page54