2008 JEEP WRANGLER maintenance

MAINTENANCE PROCEDURES
The pages that follow contain therequiredmaintenance
services determined by the engineers who designed your
vehicle.
Besides the maintenance items for which there are fixed
maintenance intervals, there are other items that should
operate satisfactorily without periodic maintenance.
However, if a malfunction of these items does occur, it
could adversely affect the engine or vehicle performance.
These items should be inspected if a malfunction is
observed or suspected.
Engine Oil
Checking Oil Level
To assure proper lubrication of your vehicle’s engine, the
engine oil must be maintained at the correct level. The
best time to check the engine oil level is about five
minutes after a fully warmed up engine is shut off or
before starting the engine after it has sat overnight. Checking the oil while the vehicle is on level ground will
improve the accuracy of the oil level readings. Always
maintain the oil level within the SAFE zone on the
dipstick. Adding 1 U.S. Quart (0.95L) of oil when the
reading is at the bottom of the SAFE zone will result in a
reading at the top of the safe zone on these engines.
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7

CAUTION!
Overfilling or underfilling the crankcase will cause
aeration or loss of oil pressure. This could damage
your engine.
Change Engine Oil
Refer to the Maintenance Schedule in Section 8 for
recommended engine oil change intervals.
Engine Oil Selection
For best performance and maximum protection for all
engines under all types of operating conditions, the
manufacturer recommends engine oils that are API Cer-
tified and meet the requirements of DaimlerChrysler
Material Standard MS-6395.
American Petroleum Institute (API) Engine Oil
Identification Symbol
This symbol means that the oil has
been certified by the American
Petroleum Institute (API). The
manufacturer only recommends
API Certified engine oils.
Engine Oil Viscosity (3.8L Engines)
SAE 5W-20 engine oil is recommended for all operating
temperatures. This engine oil improves low temperature
starting and vehicle fuel economy.
The engine oil filler cap also shows the recommended
engine oil viscosity for your engine. For information on
engine oil filler cap location, refer to the “Engine Com-
partment” illustration in this section.
384 MAINTAINING YOUR VEHICLE

Lubricants which do not have both, the engine oil certi-
fication mark and the correct SAE viscosity grade num-
ber, should not be used.
Synthetic Engine Oils
Synthetic engine oils can be used if the recommended oil
quality requirements are met, and the recommended
maintenance intervals for oil and filter changes are
followed.
Materials Added To Engine Oils
The manufacturerstrongly recommends against the ad-
dition of any additives (other than leak detection dyes) to
engine oil. Engine oil is an engineered product and its
performance may be impaired by supplemental addi-
tives.
Disposing of Used Engine Oil
Care should be taken in disposing of used engine oil from
your vehicle. Used oil, indiscriminately discarded, can
present a problem to the environment. Contact your authorized dealer, service station, or governmental
agency for advice on how and where used oil 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
All of the manufacturer’s engines have a full-flow type
disposable oil filter. Use a filter of this type for replace-
ment. The quality of replacement filters varies consider-
ably. Only high quality filters should be used to assure
most efficient service. MOPAR
engine oil filters are high
quality oil filters and are recommended.
MAINTAINING YOUR VEHICLE 385
7

Drive Belts — Check Condition and Tension
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
At the mileage indicated in the Maintenance Schedule,
the condition of all the belts and tensioner should be
checked. Refer to Section 8 of this manual. 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
generator belt tension can cause battery failure.
Also, check belt routing to make sure there is no inter-
ference between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure engine perfor-
mance and emission control. New plugs should be in-
stalled at the mileage specified in the Maintenance Sched-
ule. Refer to Section 8 of this manual. The entire set
should be replaced if there is any malfunction due to a
faulty spark plug. Refer to Fluids, Lubricants, and Genu-
ine Parts in this section for spark plug information.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
converter 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.
386 MAINTAINING YOUR VEHICLE

Engine Air Cleaner Filter
Refer to the Maintenance Schedule in Section 8 for
recommended engine air cleaner filter change intervals.
WARNING!
The air cleaner can provide protection in the case of
engine backfire. Do not remove the air cleaner unless
it 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.
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.
WARNING!
Battery posts, terminals, and related accessories con-
tain lead and lead compounds. Always wash hands
after handling the battery.
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 “fast charger” is used while battery is in the
vehicle, disconnect both vehicle battery cables before
connecting the charger to battery. Do not use a “fast
charger” to provide starting voltage.
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7

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 should
include cleaning of the condenser fins and a performance
test. Drive belt tension should also be checked at this
time.WARNING!
•Use 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.
•The 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.
390 MAINTAINING YOUR VEHICLE

Cooling System — Drain, Flush, And Refill
The cooling system should be drained, flushed, and
refilled, at the intervals shown on the Maintenance
Schedule. Refer to Section 8 of this manual.
If the solution is dirty and contains a considerable
amount of sediment, clean and flush with reliable cooling
system cleaner. Follow with a thorough rinsing to remove
all deposits and chemicals. Properly dispose of old
antifreeze/coolant solution.
Discard old antifreeze/coolant solution according to rec-
ommended procedure.
Selection Of Engine Coolant
Use only the manufacturer’s recommended antifreeze/
coolant. Refer to Fluids, Lubricants, and Genuine Parts in
this section for correct antifreeze/coolant type.
CAUTION!
•Mixing of antifreeze/coolants other than the speci-
fied HOAT antifreeze/coolants, may result in en-
gine damage and may decrease corrosion protec-
tion. If a non-HOAT antifreeze/coolant is
introduced into the cooling system in an emer-
gency, it should be replaced with the specified
antifreeze/coolant as soon as possible.
•Do not use plain water alone or alcohol-base
antifreeze/coolant products. Do not use additional
rust inhibitors or antirust products, as they may
not be compatible with the antifreeze/coolant and
may plug the radiator.
•This vehicle has not been designed for use with
Propylene Glycol based antifreeze/coolants. Use
of Propylene Glycol base antifreeze/coolants is not
recommended.
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Adding Engine Coolant
Your vehicle has been built with an improved antifreeze/
coolant that allows extended maintenance intervals. This
antifreeze/coolant can be used up to 5 Years or 100,000
mi (160 000 km) before replacement. To prevent reducing
this extended maintenance period, it is important that
you use the same antifreeze/coolant throughout the life
of your vehicle. Please review these recommendations for
using Hybrid Organic Additive Technology (HOAT)
antifreeze/coolant. When adding antifreeze/coolant:
•The manufacturer recommends using MOPAR
Antifreeze/Coolant 5 Year/100,000 Mile Formula
HOAT (Hybrid Organic Additive Technology).
•Mix a minimum solution of 50% HOAT engine coolant
and distilled water. Use higher concentrations (not to
exceed 70%) if temperatures below -34°F (-37°C) are
anticipated.
•Use 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 antifreeze/coolant types will decrease
the life of the antifreeze/coolant and will require more
frequent antifreeze/coolant changes.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss of
antifreeze/coolant, and to ensure that antifreeze/coolant
will return to the radiator from the coolant reserve tank.
396 MAINTAINING YOUR VEHICLE