2008 JEEP GRAND CHEROKEE engine

Towing Tips Ð Electronic Speed Control (If
Equipped)
þ
Don't use in hilly terrain or with heavy loads.
þWhen using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
þUse speed control in flat terrain and with light loads to
maximize fuel efficiency.
Towing Tips Ð Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
þCity Driving
When stopped for short periods of time, put transmission
in neutral and increase engine idle speed.
þHighway Driving
Reduce speed.
þAir Conditioning
Turn off temporarily.
þrefer to Cooling System Operating information in the
Maintenance section of this manual for more informa-
tion.
RECREATIONAL TOWING (BEHIND
MOTORHOME, ETC.)
Recreational towing is not allowed.
296 STARTING AND OPERATING

WHAT TO DO IN EMERGENCIES
CONTENTS
mHazard Warning Flashers.................298
mIf Your Engine Overheats.................299mJump Starting.........................300
6

IF YOUR ENGINE OVERHEATS
In any of the following situations, you can reduce the
potential for overheating by taking the appropriate ac-
tion.
²On the highways Ð Slow down.
²In city traffic Ð While stopped, put transmission in N
(Neutral), but do not increase engine idle speed.
NOTE:There are steps that you can take to slow down
an impending overheat condition. If your air conditioner
is on, turn it off. The air conditioning system adds heat to
the engine cooling system and turning off the A/C
removes this heat. You can also turn the Temperature
Control to maximum heat, the Mode Control to floor, and
the Fan Control to High. This allows the heater core to act
as a supplement to the radiator and aids in removing heat
from the engine cooling system.
CAUTION!
Driving with a hot cooling system could damage
your vehicle. If the temperature gauge reads ªHº,
pull over and stop the vehicle. Idle the vehicle with
the air conditioner turned off until the pointer drops
back into the normal range. If the pointer remains on
the ªHº, and you hear continuous chimes, turn the
engine off immediately, and call for service.
WHAT TO DO IN EMERGENCIES 299
6

1. Remove all metal jewelry such as watch bands or
bracelets which might make an unintended electrical
contact.
2. Park the booster vehicle within cable reach but with-
out letting the vehicles touch. Set the parking brake on
both vehicles, place the transmission in P (Park), and turn
the ignition OFF.
3. Turn off the heater, radio, and all unnecessary electri-
cal loads.
4. Connect one end of a jumper cable to the positive
terminal of the booster battery. Connect the other end of
the same cable to the positive terminal of the discharged
battery.WARNING!
Do not permit vehicles to touch each other as this
could establish a ground connection and personal
injury could result.
5. Connect the other cable, first to the negative terminal
of the booster battery and then to the engine of the
vehicle with the discharged battery. Make sure you have
a good contact on the engine.
6. Start the engine in the vehicle which has the booster
battery, let the engine idle a few minutes, then start the
engine in the vehicle with the discharged battery.
7. When removing the jumper cables, reverse the above
sequence exactly. Be careful of the moving belts and fan.
WHAT TO DO IN EMERGENCIES 301
6

MAINTAINING YOUR VEHICLE
CONTENTS
mEngine Compartment ± 6.1L...............306
mOnboard Diagnostic System Ð OBD II........307
NLoose Fuel Filler Cap Message............308
mEmissions Inspection And Maintenance
Programs............................308
mReplacement Parts......................310
mDealer Service.........................310
mMaintenance Procedures..................311
NEngine Oil..........................311NEngine Oil Filter......................315
NDrive Belts Ð Check Condition And
Tensioner...........................315
NSpark Plugs.........................316
NEngine Air Cleaner Filter................316
NFuel Filter..........................317
NCatalytic Converter....................317
NMaintenance-Free Battery................318
NAir Conditioner Maintenance.............319
7

NFront Turn Signal.....................349
NFront Fog Light......................350
NRear Tail, Stop, Turn Signal, And Back-Up
Lights.............................350
NCenter High Mounted Stop Light (CHMSL) . . . 351mFluid Capacities........................352
mFluids, Lubricants, And Genuine Parts........353
NEngine.............................353
NChassis............................354
MAINTAINING YOUR VEHICLE 305
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ENGINE COMPARTMENT ± 6.1L
306 MAINTAINING YOUR VEHICLE

ONBOARD DIAGNOSTIC SYSTEM Ð OBD II
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBD II. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the ªMalfunction Indicator Light.º It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your dealer for service as soon as
possible.CAUTION!
²Prolonged driving with the ªMalfunction Indica-
tor Lightº on could cause further damage to the
emission control system. It could also affect fuel
economy and driveability. The vehicle must be
serviced before any emissions tests can be per-
formed.
²If the ªMalfunction Indicator Lightº is flashing
while the engine is running, severe catalytic con-
verter damage and power loss will soon occur.
Immediate service is required.
MAINTAINING YOUR VEHICLE 307
7