Jeep TJ (2006 year). Manual — part 18

• More than 50% of your driving is at sustained high

speeds during hot weather, above 90°F (32°C)

• Taxi, Police, or delivery service (commercial service)
• Trailer towing
• Off-road or desert driving
• If equipped for and operating with E–85 (ethanol) fuel

If ANY of these apply to you, then change your engine oil
at every interval shown in schedule “B” of the “Mainte-
nance Schedules” section of this manual.

If none of these apply to you, then change your engine oil
at every interval shown on schedule “A” of the “Main-
tenance Schedules” section of this manual

NOTE:

Under no circumstances should oil change in-

tervals exceed 6,000 miles (10 000 km) or 6 months
whichever comes first.

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.

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Engine Oil Viscosity (2.4L Engines)
SAE 5W-30 engine oil is recommended for all operating
temperatures. This engine oil improves low tempera-
ture starting and vehicle fuel economy. Your engine oil
filler cap shows the recommended engine oil viscosity
for your vehicle.

Engine Oil Viscosity (4.0L Engines)
SAE 10W-30 engine oil is recommended for all operat-
ing temperatures. This engine oil improves low tem-
perature starting and vehicle fuel economy. Your engine
oil filler cap shows the recommended engine oil vis-
cosity for 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.

Materials Added To Engine Oils
The manufacturer strongly recommends against the ad-
dition of any additives (other than leak detection dyes) to
engine oil. Engine oil is an engineered product and it’s
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.

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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

威 engine oil filters are high

quality oil filters and are recommended.

Drive Belts — Check Condition and Tension
At the mileage shown in the appropriate “Maintenance
Schedule,” check all drive belts for condition and proper
tension. Improper belt tension can cause belt slippage
and failure.

Inspect the drive belt for evidence of cuts, cracks, or
glazing and replace them if there is any sign of damage
which could result in belt failure. If adjustment is re-
quired, adjust the belts according to the specifications
and procedures shown in the Service Manual.

Special tools are required to properly measure tension
and to restore belt tension to factory specifications. Also,
check belt routing to make sure there is no interference
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 appropriate main-
tenance chart. The entire set should be replaced if there is
any malfunction due to a faulty spark plug.

Refer to the “Vehicle Emission Control Information” label
in the engine compartment 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.

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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
vehicle.

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 ex-
haust system. Do not park or operate your vehicle in
areas where your exhaust system can contact any-
thing that can burn.

In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune up to manufacturer’s specifica-
tions, should be obtained immediately.

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To minimize the possibility of catalytic converter dam-
age:

• Do not shut off the engine or interrupt the ignition

when the transmission is in gear and the vehicle is in
motion.

• Do not try to start the engine by pushing or towing the

vehicle.

• Do not idle the engine with any spark plug wires

disconnected or removed, such as when diagnostic
testing.

• Do not idle the engine for prolonged periods during

very rough idle or malfunctioning operating conditions.

• Do not allow vehicle to run out of fuel.

NOTE:

Intentional tampering with emissions control

systems can result in civil penalties being assessed
against you.

Engine Timing Belt — 2.4L Engine

Replace the engine timing belt at the intervals described
in the appropriate maintenance schedule.

Ignition Wiring System — 2.4L Engine

Replace the ignition cables at the intervals described in
the appropriate maintenance schedule.

Crankcase Emission Control System
Proper operation of this system depends on freedom
from sticking or plugging due to deposits. As vehicle
mileage builds up, the PCV valve and passages may
accumulate deposits. If a valve is not working properly,
replace it with a new valve. DO NOT ATTEMPT TO
CLEAN THE OLD PCV VALVE!

Check ventilation hose for indication of damage or
plugging deposits. Replace if necessary.

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Fuel Filter
A plugged fuel filter can cause hard starting or limit the
speed at which a vehicle can be driven. Should an
excessive amount of dirt accumulate in the fuel tank,
frequent replacement of the fuel filter which is mounted
in the fuel tank may be necessary.

Engine Air Cleaner Filter
Under normal driving conditions, replace the air filter at
the intervals shown on “Maintenance Schedule A.” 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 “Maintenance Schedule B.”

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 compart-
ment 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.

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WARNING!

Battery posts, terminals, and related accessories con-
tain lead and lead compounds. Always wash hands
after handling the battery.

To determine the battery charge, check the battery test
indicator (if equipped) on top of the battery. Refer to the
illustration.

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 be-
fore connecting the charger to battery. Do not use a
“fast charger” to provide starting voltage.

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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
additional 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.

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Refrigerant Recovery and Recycling
R-134a Air Conditioning Refrigerant is a hydrofluorocar-
bon (HFC) that is endorsed by the Environmental Pro-
tection Agency and is an ozone-saving product. How-
ever, the manufacturer recommends that air conditioning
service be performed by dealers or other service facilities
using recovery and recycling equipment.

Power Steering Fluid Check
Checking the power steering fluid level at a defined
service interval is not required. The fluid should only be
checked if a leak is suspected, abnormal noises are
apparent, and/or the system is not functioning as antici-
pated. Coordinate inspection efforts through a certified
DaimlerChrysler Dealership.

⬙

WARNING!

Fluid level should be checked on a level surface with
the engine off to prevent injury from moving parts,
and to insure accurate fluid level reading. Do not
overfill. Use only the manufacturer’s recommended
fluid.

If necessary, add fluid to restore to the proper indicated
level. With a clean cloth, wipe any spilled fluid from all
surfaces. Refer to Fluids, Lubricants, and Genuine Parts
for correct fluid type.

NOTE:

Upon initial start-up in cold weather, the power

steering pump may make noise for a short period of time.
This is due to the cold, thick fluid in the steering system.
This noise should be considered normal, and does not in
any way damage the steering system.

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Driveline And Steering Component Lubrication
U-joints (cardan joints) are sealed and do not require
lubrication. Prop shafts, yokes, ball joints and other
driveline and steering components may be provided with
grease fittings for lubrication. Lubrication of these com-
ponents at the intervals specified in the appropriate
“Maintenance Schedule” in Section 8 is very important,
particularly if your vehicle is subjected to off-road or
other heavy-duty use. See your authorized dealer for
complete service information.

Body Lubrication
Locks and all body pivot points, including such items as
seat tracks, doors, tailgate and hood hinges, should be
lubricated periodically to assure quiet, easy operation
and to protect against rust and wear. Prior to the appli-
cation of any lubricant, the parts concerned should be
wiped clean to remove dust and grit; after lubricating
excess oil and grease should be removed. Particular

attention should also be given to hood latching compo-
nents to insure proper function. When performing other
underhood services, the hood latch, release mechanism
and safety catch should be cleaned and lubricated.

The external lock cylinders should be lubricated twice a
year, preferably in the fall and spring. Apply a small
amount of a high quality lubricant such as Mopar

威 Lock

Cylinder Lubricant directly into the lock cylinder.

Windshield Wiper Blades
Clean the rubber edges of the wiper blades and the
windshield periodically with a sponge or soft cloth and a
mild non-abrasive cleaner. This will remove accumula-
tions of salt or road film.

Operation of the wipers on dry glass for long periods
may cause deterioration of the wiper blades. Always use
washer fluid when using the wipers to remove salt or dirt
from a dry windshield. Avoid using the wiper blades to

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remove frost or ice from the windshield. Keep the blade
rubber out of contact with petroleum products such as
engine oil, gasoline, etc.

Windshield Washers

The fluid reservoir in the engine compartment should be
checked for fluid level at regular intervals. Fill the

reservoir with windshield antifreeze (not radiator anti-
freeze) rated not to freeze at -25°F (-31°C). Operate the
system for a few seconds to flush out the residual water.

WARNING!

Commercial windshield washer solvents are flam-
mable. They could ignite and burn you. Care must
be exercised when filling or working around the
washer solution.

Exhaust System
The best protection against carbon monoxide entry into
the vehicle body is a properly maintained engine exhaust
system.

If you notice a change in the sound of the exhaust system;
or if the exhaust fumes can be detected inside the vehicle;
or when the underside or rear of the vehicle is damaged;

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have an authorized technician inspect the complete ex-
haust system and adjacent body areas for broken, dam-
aged, deteriorated, or mispositioned parts. Open seams
or loose connections could permit exhaust fumes to seep
into the passenger compartment. In addition, inspect the
exhaust system each time the vehicle is raised for lubri-
cation or oil change. Replace as required.

Cooling System

WARNING!

You or others can be badly burned by hot antifreeze/
coolant or steam from your radiator. If you see or
hear steam coming from under the hood, don’t open
the hood until the radiator has had time to cool.
Never try to open a cooling system pressure cap
when the radiator or coolant bottle is hot.

Engine Coolant Checks
Check antifreeze/coolant protection every 12 months
(before the onset of freezing weather, where applicable).
If antifreeze/coolant is dirty or rusty in appearance, the
system should be drained, flushed and refilled with fresh
antifreeze/coolant. Check the front of the A/C condenser
(if equipped) or radiator for any accumulation of bugs,
leaves, etc. If dirty, clean by gently spraying water from a
garden hose vertically down the face of the A/C con-
denser (if equipped) or the back of the radiator core.

Check the engine cooling system hoses for brittle rubber,
cracking, tears, cuts, and tightness of the connection at
the coolant recovery bottle and radiator. Inspect the
entire system for leaks.

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With the engine at normal operating temperature (but
not running), check the cooling system pressure cap for
proper vacuum sealing by draining a small amount of
antifreeze/coolant from the radiator drain cock. If the cap
is sealing properly, the antifreeze/coolant will begin to
drain from the coolant recovery bottle. DO NOT RE-
MOVE THE COOLANT PRESSURE CAP WHEN THE
COOLING SYSTEM IS HOT.

Cooling System — Drain, Flush, And Refill
At the intervals shown in the appropriate “Maintenance
Schedule,” the system should be drained, flushed, and
refilled.

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 for
correct antifreeze/coolant type.

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CAUTION!

• Mixing of antifreeze/coolant other than the speci-

fied HOAT antifreeze/coolant may result in de-
creased corrosion protection and engine damage.
If a non-HOAT antifreeze/coolant is introduced
into the cooling system in an emergency, 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/coolant. Use of
Propylene Glycol base antifreeze/coolant is not
recommended.

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
miles before replacement. To prevent reducing this ex-
tended 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, a minimum solution of
50% recommended Mopar Antifreeze/ Coolant 5 Year/
100,000 Mile Formula HOAT (Hybrid Organic Additive
Technology), or equivalent, in water should be used. Use
higher concentrations (not to exceed 70%) if temperatures
below -34°F (-37°C) are anticipated.

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Use only high purity water such as distilled or deionized
water when mixing the water/antifreeze (coolant) solu-
tion. 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 insure that antifreeze/coolant
will return to the radiator from the coolant reserve tank.

The cap should be inspected and cleaned if there is any
accumulation of foreign material on the sealing surfaces.

WARNING!

The warning words DO NOT OPEN HOT on the
cooling system pressure cap are a safety precaution.
Never add antifreeze/coolant when the engine is
overheated. Do not loosen or remove the cap to cool
an overheated engine. Heat causes pressure to build
up in the cooling system. To prevent scalding or
injury, do not remove the pressure cap while the
system is hot or under pressure.

Disposal of Used Engine Coolant
Used ethylene glycol based antifreeze/coolant is a regu-
lated substance requiring proper disposal. Check with
your local authorities to determine the disposal rules for
your community. To prevent ingestion by animals or

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children, do not store ethylene glycol based antifreeze/
coolant in open containers or allow it to remain in
puddles on the ground. If ingested by a child, contact a
physician immediately. Clean up any ground spills im-
mediately.

Engine Coolant Level
The coolant bottle provides a quick visual method for
determining that the coolant level is adequate. With the
engine idling, and warm to normal operating tempera-
ture, the level of the antifreeze/coolant in the bottle
should be between the ranges indicated on the bottle.

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 of

operation, you may observe vapor coming from the front
of the engine compartment. This is normally a result of
moisture from rain, snow, or high humidity accumulat-
ing on the radiator and being vaporized 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.

• Do not overfill the coolant bottle.

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