2008 JEEP GRAND CHEROKEE maintenance

Synthetic Engine Oils
You may use synthetic engine oils provided the recom-
mended oil quality requirements are met, and the recom-
mended maintenance intervals for oil and filter changes
are followed.
Materials Added to Engine Oil
The manufacturer strongly recommends against the ad-
dition of any additives (other than leak detection dyes) to
the engine oil. Engine oil is an engineered product and
it's performance may be impaired by supplemental ad-
ditives.
Disposing of Used Engine Oil And Oil Filters
Care should be taken in disposing of used engine oil and
oil filters from your vehicle. Used oil and oil filters,
indiscriminately discarded, can present a problem to the
environment. Contact your dealer, service station, or
governmental agency for advice on how and where used
oil and oil filters can be safely discarded in your area.
Engine Oil Filter
The engine oil filter should be replaced at every engine
oil change.
Engine Oil Filter Selection
The manufacturer's engines have a full-flow type oil
filter. Use a filter of this type for replacement. The quality
of replacement filters varies considerably. Only high
quality filters should be used to assure most efficient
service. Mopar Engine Oil Filters are a high quality oil
filter and are recommended.
Drive Belts Ð Check Condition and Tensioner
Belt tension is controlled by means of an automatic
tensioner. No belt tension adjustments are required.
However, belt and belt tensioner condition should be
inspected at the specified intervals, and replaced if re-
quired. See your authorized dealer for service.
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At the mileage indicated on the appropriate ªMainte-
nance Schedule,º all belts and tensioner should be
checked for condition. Improper belt tension can cause
belt slippage and failure.
Belts should be inspected for evidence of cuts, cracks,
glazing, or frayed cords and replaced if there is indication
of damage which could result in belt failure. Low gen-
erator belt tension can cause battery failure.
Also check belt routing to make sure there is no interfer-
ence between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure engine perfor-
mance and emission control. New spark plugs should be
installed at the specified mileage. The entire set should be
replaced if there is any malfunction due to a faulty spark
plug. Refer to ªFluids, Lubricants, and Genuine Partsº in
this section for spark plug information.
Engine Air Cleaner Filter
Under normal driving conditions, replace the air filter at
the intervals shown on ªMaintenance Schedule A.º If,
however, you drive the vehicle frequently under dusty or
severe conditions, the filter element should be inspected
periodically and replaced if necessary at the intervals
shown on ªMaintenance Schedule B.º
WARNING!
The air cleaner can provide a measure of protection
in the case of engine backfire. Do not remove the air
cleaner unless such removal is necessary for repair or
maintenance. Make sure that no one is near the
engine compartment before starting the vehicle with
the air cleaner removed. Failure to do so can result in
serious personal injury.
316 MAINTAINING YOUR VEHICLE

Fuel Filter
A plugged fuel filter can cause stalling, limit the speed at
which a vehicle can be driven or cause hard starting.
Should an excessive amount of dirt accumulate in the
fuel tank, filter replacement may be necessary. See your
local dealer for service.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
catalyst as an emission control device.
Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
CAUTION!
Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition. In
the event of engine malfunction, particularly involv-
ing engine misfire or other apparent loss of perfor-
mance, have your vehicle serviced promptly. Contin-
ued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and the
vehicle.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
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WARNING!
A hot exhaust system can start a fire if you park over
materials that can burn. Such materials might be
grass or leaves coming into contact with your exhaust
system. Do not park or operate your vehicle in areas
where your exhaust system can contact anything that
can burn.
In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may indicate severe
and abnormal catalyst overheating. If this occurs, the
vehicle should be stopped, the engine shut off and the
vehicle allowed to cool. Thereafter, service, including a
tune-up to manufacturer's specifications, should be ob-
tained immediately.To minimize the possibility of catalyst damage:²Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
²Do not try to start engine by pushing or towing the
vehicle.
²Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough
idling or malfunctioning operating conditions.
Maintenance-Free Battery
Your vehicle is equipped with a maintenance-free battery.
You will never have to add water, nor is periodic main-
tenance required.
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CAUTION!
It is essential when replacing the cables on the
battery that the positive cable is attached to the
positive post and the negative cable is attached to the
negative post. Battery posts are marked (+) positive
and negative (-) and identified on the battery case.
Also, if a ªfast chargerº is used while battery is in the
vehicle, disconnect both vehicle battery cables before
connecting the charger to battery. Do not use a ªfast
chargerº to provide starting voltage.
Air Conditioner Maintenance
For best possible performance, your air conditioner
should be checked and serviced by an Authorized Dealer
at the start of each warm season. This service shouldinclude cleaning of the condenser fins and a performance
test. Drive belt tension should also be checked at this
time.
WARNING!
²Use only refrigerants and compressor lubricants
approved by the manufacturer for your air condi-
tioning system. Some unapproved refrigerants are
flammable and can explode, injuring you. Other
unapproved refrigerants or lubricants can cause
the system to fail, requiring costly repairs. Refer
to Section 3 of the Warranty Information Book for
further warranty information.
²The air conditioning system contains refrigerant
under high pressure. To avoid risk of personal
injury or damage to the system, adding refrigerant
or any repair requiring lines to be disconnected
should be done by an experienced repairman.
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drain from the coolant recovery bottle. DO NOT RE-
MOVE THE COOLANT PRESSURE CAP WHEN THE
COOLING SYSTEM IS HOT.
Cooling System Ð Drain, Flush and Refill
At the intervals shown on the appropriate ªMaintenance
Schedule,º the system should be drained, flushed and
refilled.
If the solution is dirty or contains a considerable amount
of sediment, clean and flush with a reliable cooling
system cleaner. Follow with a thorough rinsing to remove
all deposits and chemicals. Properly dispose of old
antifreeze solution.
Selection Of Coolant
Use only the manufacturer's recommended coolant, refer
to Fluids, Lubricants and Genuine Parts for correct
coolant type.
CAUTION!
Mixing of coolants other than specified HOAT en-
gine coolants, may result in engine damage and may
decrease corrosion protection. If a non-HOAT coolant
is introduced into the cooling system in an emer-
gency, it should be replaced with the specified cool-
ant as soon as possible.
Do not use plain water alone or alcohol base engine
coolant (antifreeze) products. Do not use additional
rust inhibitors or antirust products, as they may not
be compatible with the radiator engine coolant and
may plug the radiator.
This vehicle has not been designed for use with
Propylene Glycol based coolants. Use of Propylene
Glycol based coolants is not recommended.
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Adding Coolant
Your vehicle has been built with an improved engine
coolant that allows extended maintenance intervals. This
coolant can be used up to 5 Years or 100,000 miles (160
000 km) before replacement. To prevent reducing this
extended maintenance period, it is important that you
use the same coolant throughout the life of your vehicle.
Please review these recommendations for using Hybrid
Organic Additive Technology (HOAT) coolant.
When adding coolant:
²The manufacturer recommends using Mopart
Antifreeze/ Coolant 5 Year/100,000 Mile Formula
HOAT (Hybrid Organic Additive Technology)
²Mix a minimum solution of 50% HOAT engine coolant
and distilled water. Use higher concentrations (not to
exceed 70%) if temperatures below234ÉF (237ÉC ) are
anticipated.
²Use only high purity water such as distilled or deion-
ized water when mixing the water/engine coolant
solution. The use of lower quality water will reduce
the amount of corrosion protection in the engine
cooling system.
Please note that it is the owner's responsibility to main-
tain the proper level of protection against freezing ac-
cording to the temperatures occurring in the area where
the vehicle is operated.
NOTE:Mixing coolant types will decrease the life of the
engine coolant and will require more frequent coolant
changes.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss of
coolant, and to insure that coolant will return to the
radiator from the coolant recovery bottle.
326 MAINTAINING YOUR VEHICLE

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 coolant 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 those hoses nearest to high
heat sources such as the exhaust manifold. Inspect hose
routing to be sure hoses do not come in contact with any
heat source or moving component which 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 cou-
plings to make sure they are secure and no leaks are
present.
Components should be replaced immediately if there is
any evidence of wear or damage that could cause failure.
Brake System
In order to assure brake system performance, all brake
system components should be inspected periodically.
Suggested service intervals can be found on the appro-
priate ªMaintenance Schedule.º Refer to Section 8 of this
manual.
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