JEEP GRAND CHEROKEE 2008 WK / 3.G Owners Manual

The radiator normally remains completely full, so there is
not need to remove the radiator cap unless checking for
antifreeze/coolant freeze point or replacing antifreeze/
coolant. Advise your service attendant of this. As long as
the engine operating temperature is satisfactory, the
coolant bottle need only be checked once a month.
When additional antifreeze/coolant is needed to main-
tain the proper level, it should be added to the coolant
bottle. Do not overfill.
Points To Remember
NOTE:When the vehicle is stopped after a few miles
(kilometers) of operation, you may observe vapor coming
from the front of the engine compartment. This is nor-
mally a result of moisture from rain, snow, or high
humidity accumulating on the radiator and being vapor-
ized when the thermostat opens, allowing hot antifreeze/
coolant to enter the radiator.If an examination of your engine compartment shows no
evidence of radiator or hose leaks, the vehicle may be
safely driven. The vapor will soon dissipate.
²Do not overfill the coolant recovery bottle.
²Check antifreeze/coolant freeze point in the radiator
and in the coolant recovery bottle. If antifreeze/
coolant needs to be added, contents of coolant recov-
ery bottle must also be protected against freezing.
²If frequent antifreeze/coolant additions are required,
or if the level in the coolant recovery bottle does not
drop when the engine cools, the cooling system should
be pressure tested for leaks.
²Maintain antifreeze/coolant concentration at 50%
HOAT antifreeze/coolant (minimum) and distilled
water for proper corrosion protection of your engine
which contains aluminum components.
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²Make sure that the radiator and coolant recovery
bottle hoses are not kinked or obstructed.
²Keep the front of the radiator clean. If your vehicle is
equipped with air conditioning, keep the front of the
condenser clean, also.
²Do not change the thermostat for summer or winter
operation. If replacement is ever necessary, install
ONLY the correct type thermostat. Other designs may
result in unsatisfactory cooling performance, poor gas
mileage, and increased emissions.
Hoses and Vacuum/Vapor Harnesses
Inspect surfaces of hoses and nylon tubing for evidence
of heat and mechanical damage. Hard or soft spots,
brittle rubber, cracking, tears, cuts, abrasions, and exces-
sive swelling indicate deterioration of the rubber.Pay particular attention to the hoses nearest to high heat
sources such as the exhaust manifold. Inspect hose rout-
ing to be sure hoses do not touch any heat source or
moving component that may cause heat damage or
mechanical wear.
Insure nylon tubing in these areas has not melted or
collapsed. Inspect all hose connections such as clamps
and couplings to make sure they are secure and no leaks
are present. Components should be replaced immedi-
ately if there is any evidence of degradation that could
cause failure.Fuel System Connections
Electronic Fuel Injection high pressure fuel systems are
designed with tubes and special connects, connections
and clamps which have unique material characteristics to
provide adequate sealing and resist attack by deterio-
rated gasoline.
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You are urged to use only the manufactures-specified
tubes, connections and clamps, or their equivalent in
material and specification, in any fuel system servicing.
Brake System
In order to assure brake system performance, all brake
system components should be inspected periodically.
Refer to the Maintenance Schedule in Section 8 for
suggested service intervals.
WARNING!
Riding the brakes can lead to brake failure and
possibly an accident. Driving with your foot resting
or riding on the brake pedal can result in abnormally
high brake temperatures, excessive lining wear, and
possible brake damage. You wouldn't have your full
braking capacity in an emergency.
Brake and Power Steering System Hoses
When servicing the vehicle for scheduled maintenance,
inspect surface of hoses for evidence of heat and me-
chanical damage. Hard and brittle rubber, cracking, tears,
cuts, abrasion, and excessive swelling suggest deteriora-
tion of the rubber. Particular attention should be made to
examining those hose surfaces nearest to high heat
sources, such as the exhaust manifold.
Inspect all hose clamps and couplings to make sure they
are secure and no leaks are present.
NOTE:Often fluids such as oil, power steering fluid,
and brake fluid are used during assembly plant opera-
tions to ease the assembly of hoses to couplings. There-
fore, oil wetness at the hose-coupling area is not neces-
sarily an indication of leakage. Actual dripping of hot
fluid when systems are under pressure (during vehicle
operation) should be noted before hose is replaced based
on leakage.
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NOTE:Inspection of brake hoses should be performed
whenever the brake system is serviced and every engine
oil change. Inspect hydraulic brake hoses for surface
cracking, scuffing, or worn spots. If there is any evidence
of cracking, scuffing, or worn spots, the hose should be
replaced immediately! Eventual deterioration of the hose
can take place resulting in a possibility of a burst failure.
WARNING!
Worn brake hoses can burst and cause brake failure.
You could have an accident. If you see any signs of
cracking, scuffing, or worn spots, have the brake
hoses replaced immediately.
Brake Master Cylinder Ð Brake Fluid Level Check
The fluid level of the master cylinder should be checked
when performing under the hood service, or immedi-
ately if the brake system warning lamp indicates system
failure.
The brake master cylinder has a translucent plastic
reservoir. On the outboard side of the reservoir, there is a
ªMAXº dot and an ªMINº dot. The fluid level must be
kept within these two dots. Do not add fluid above the
MAX mark, because leakage may occur at the cap.
With disc brakes the fluid level can be expected to fall as
the brake linings wear. However, an unexpected drop in
fluid level may be caused by a leak and a system check
should be conducted.
Refer to Fluids, Lubricants and Genuine Parts for the
correct fluid type.
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WARNING!
Use of a brake fluid that may have a lower initial
boiling point, or is unidentified as to specification,
may result in sudden brake failure during hard
prolonged braking. You could have an accident.
WARNING!
Overfilling the brake fluid reservoir can result in
spilling brake fluid on hot engine parts and the
brake fluid catching fire.
Use only brake fluid that has been in a tightly closed
container to avoid contamination from foreign matter or
moisture.
CAUTION!
Do not allow a petroleum-base fluid to contaminate
the brake fluid. Seal damage may result.
Front/Rear Axle Fluid
Front Axle Fluid Level Check
Lubricant should be to the bottom of the oil fill hole.
Rear Axle Fluid Level Check
Lubricant should be 1/2º (1 cm) below the oil fill hole.
Adding Fluid
Add lubricant only at the fill hole and only to the level
specified above.
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Selection of Lubricant
Use only manufacturer's recommended fluid, refer to
Fluids, Lubricants, and Genuine Parts for correct fluid
type.
Transfer Case
Fluid Level Check
Inspect the transfer case for fluid leaks. If a fluid leak is
found, the transfer case fluid level can be checked by
removing the filler plug located on the back side of the
transfer case. The fluid level should be at the bottom edge
of the filler plug hole when the vehicle is in a level
position.
Adding Fluid
Add fluid at the filler hole until it runs out of the hole
when the vehicle is in a level position.
Drain
First remove fill plug, then remove drain plug. Recom-
mended tightening torque for drain and fill plugs is
15±25 ft. lbs (20±34 N´m).
CAUTION!
When installing plugs, do not overtighten. You could
damage them and cause them to leak.
Selection of Lubricant
Use only manufacturer's recommended fluid, refer to
Fluids, Lubricants, and Genuine Parts for correct fluid
type.
416 MAINTAINING YOUR VEHICLE

Automatic Transmission
Selection of Lubricant
It is important that the proper lubricant is used in the
transmission to assure optimum transmission perfor-
mance. Use only manufacturer's recommended transmis-
sion fluid, refer to Fluids, Lubricants, and Genuine Parts
for correct fluid type. It is important that the transmission
fluid be maintained at the prescribed level using the
recommended fluid.
CAUTION!
Using a transmission fluid other than the manufactur-
er's recommended fluid may cause deterioration in
transmission shift quality and/or torque converter
shudder. Using a transmission fluid other than the
manufacturer's recommended fluid will result in more
frequent fluid and filter changes. Refer to Fluids,
Lubricants, and Genuine Parts for correct fluid type.
Special Additives
Automatic Transmission Fluid (ATF) is an engineered
product and its performance may be impaired by supple-
mental additives. Therefore, do not add any fluid addi-
tives to the transmission. The only exception to this
policy is the use of special dyes to aid in detecting fluid
leaks. In addition, avoid using transmission sealers as
they may adversely affect seals.
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Fluid Level Check (3.7L and 3.0L Diesel Engine)
Regular automatic transmission fluid level checks are not
required. For this reason, the dipstick is omitted.
If you notice fluid loss or gear shift malfunction, have
your authorized dealer check the transmission fluid level.CAUTION!
²Using a transmission fluid other than the manu-
facturer's recommended fluid may cause deterio-
ration in transmission shift quality and/or torque
converter shudder. Using a transmission fluid
other than that recommended by the manufacturer
will result in more frequent fluid and filter
changes. Refer to ªFluids, Lubricants, and Genu-
ine Partsº for the correct fluid type.
²The fluid level is preset at the factory and it does
not require adjustment under normal operating
conditions. If a transmission fluid leak occurs,
visit your authorized dealer immediately. Severe
damage to the transmission may occur. Your au-
thorized dealer has the proper tools to adjust the
fluid level accurately.
418 MAINTAINING YOUR VEHICLE

Fluid Level Check (4.7L and 5.7L Engine)
Check the fluid level while the transmission is at normal
operating temperature. This occurs after at least 15 miles
(25 km) of driving. At normal operating temperature the
fluid cannot be held comfortably between the fingertips.
To check the automatic transmission fluid level properly,
the following procedure must be used:
1. Operate the engine at idle speed and normal operating
temperature.
2. The vehicle must be on level ground.
3. Fully apply the parking brake and press the brake
pedal.
4. Place the gear selector momentarily in each gear
position ending with the lever in P (Park).
5. Remove the dipstick, wipe it clean and reinsert it until
seated.6. Remove the dipstick again and note the fluid level on
both sides. The fluid level should be between the ªHOTº
(upper) reference holes on the dipstick at normal operat-
ing temperature. The fluid level is only valid if there is a
solid coating of oil is seen on both sides of the dipstick. If
the fluid is low, add as required into the dipstick tube.Do
not overfill.After adding any quantity of oil through the
oil fill tube, wait a minimum of two (2) minutes for the oil
to fully drain into the transmission before rechecking the
fluid level.
NOTE:If it is necessary to check the transmissionbelow
the operating temperature, the fluid level should be
between the two ªCOLDº (lower) holes on the dipstick
with the fluid at approximately 70ÉF (21ÉC) (room tem-
perature). If the fluid level is correctly established at
room temperature, it should be between the ªHOTº
(upper) reference holes when the transmission reaches
180ÉF (82ÉC). Remember it is best to check the level at the
normal operating temperature.
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7

CAUTION!
Be aware that if the fluid temperature is below 50ÉF
(10ÉC) it may not register on the dipstick. Do not add
fluid until the temperature is elevated enough to
produce an accurate reading.
7. Check for leaks. Release parking brake.
To prevent dirt and water from entering the transmission
after checking or replenishing fluid, make certain that the
dipstick cap is properly reseated. It is normal for the
dipstick cap to spring back slightly from its fully seated
position, as long as its seal remains engaged in the
dipstick tube.
Maintenance After Off-Road Driving
After extended operation in mud, sand or water, or
similar dirty conditions, have your brake discs, brake
linings, and axle joints inspected and cleaned as soon as
possible. This will prevent any abrasive material from
causing excessive wear or unpredictable braking action.
After driving off-road, completely inspect the underbody
of your vehicle. Check tires, body structure, steering,
suspension and exhaust system for damage. Check
threaded fasteners for looseness, particularly on the
chassis, drivetrain components, steering and suspension.
Retighten, if required, to torque values specified in the
Service Manual. Also check for accumulations of vegeta-
tion or brush that could become a fire hazard, or conceal
damage to fuel lines, brake hoses, axle pinion seals, and
propeller shafts.
420 MAINTAINING YOUR VEHICLE