engine JEEP WRANGLER 2004 TJ / 2.G Repair Manual

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.
To minimize the possibility of catalytic converter dam-
age:
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 the 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.
²Do not idle the engine for prolonged periods during
very rough idle or malfunctioning operating condi-
tions.
²Do 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 Ð 2.4L Engine
Replace the engine timing belt at the intervals described
in the appropriate maintenance schedule.
Ignition Wiring System Ð 2.4L Engine
Replace the ignition cables at the intervals described in
the appropriate maintenance schedule.
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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.
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 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 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.
WARNING!
Battery posts, terminals, and related accessories con-
tain lead and lead compounds. Always wash hands
after handling the battery.
234 MAINTAINING YOUR VEHICLE

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.
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.
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.
NOTE:Air Conditioning systems found to be contami-
nated with A/C System Sealers, Stop Leak Products, Seal
Conditioners, Compressor Oil, or Refrigerants not ap-
proved by the manufacturer, voids the warranty for the
Air Conditioning system.
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.9
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.
236 MAINTAINING YOUR VEHICLE

If necessary, add fluid to restore to the proper indicated
level. With a clean cloth, wipe any spilled fluid from all
surfaces. Refer to Recommended Fluids, Lubricants, and
Genuine Parts for correct fluid type.
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
ªMaintenance Scheduleº 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. Particularattention 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 MopartLock
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
remove frost or ice from the windshield. Keep the blade
rubber out of contact with petroleum products such as
engine oil, gasoline, etc.
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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 -25ÉF (-31ÉC). 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.
Windshield Washer Aiming
To change the aim of the windshield washers, place a
safety pin into the nozzle opening and move the nozzle
slightly. Continue making slight adjustments until you
obtain the desired pattern.
Exhaust System
The best protection against carbon monoxide entry into
the vehicle body is a properly maintained engine exhaust
system.
238 MAINTAINING YOUR VEHICLE

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;
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 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 radia-
tor or coolant bottle is hot.
Coolant Checks
Check coolant protection every 12 months (before the
onset of freezing weather, where applicable). If coolant is
dirty or rusty in appearance, the system should be
drained, flushed and refilled with fresh coolant.
Check the front of the radiator for any accumulation of
bugs, leaves, etc. Clean the radiator by gently spraying
water from a garden hose at the back of the core.
Check the engine cooling system hoses for condition and
tightness of connection. Inspect the entire system for
leaks. Any hoses that show cuts or severe abrasion must
be replaced.
Cooling System Ð Drain, Flush, And Refill
At the intervals shown in the appropriate ªMaintenance
Schedule,º 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.
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Engine Coolant Disposal
Used ethylene glycol based engine coolant is a regulated
substance requiring proper disposal. Check with your
local authorities to determine the disposal rules for your
community. Do not store ethylene glycol based engine
coolant in open containers or allow it to remain in
puddles on the ground. Prevent ingestion by animals or
children. If ingested by a child, contact a physician
immediately.
Selection Of Coolant
Use only the manufacturer's recommended coolant, refer
to Recommended Fluids, Lubricants, and Genuine Parts
for correct coolant type.
CAUTION!
²Mixing of coolants other than the specified HOAT
coolant may result in decreased corrosion protec-
tion and engine damage that may not be covered
under the new vehicle warranty. If a non-HOAT
coolant is introduced into the cooling system in an
emergency, it should be replaced with the speci-
fied coolant as soon as possible.
²Do not use plain water alone or alcohol base
antifreeze products. Do not use additional rust
inhibitors or antirust products, as they may not be
compatible with the radiator coolant and may
plug the radiator.
²This vehicle has not been designed for use with
Propylene Glycol based coolants. Use of Propy-
lene Glycol base coolants is not recommended.
240 MAINTAINING YOUR VEHICLE

Adding Coolant
When adding coolant, a minimum solution of recom-
mended 50% ethylene glycol antifreeze coolant in water
should be used. Use higher concentrations (not to exceed
70%) if temperatures below -37ÉF (-38ÉC) are anticipated.
Use only high purity water such as distilled or deionized
water when mixing the water/antifreeze solution. The
use of lower quality water will reduce the amount of
corrosion protection in the engine cooling system.
NOTE:Mixing coolant types will decrease the life of the
engine coolant and will require more frequent engine
coolant changes.
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.
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 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 coolant when the engine is overheated.
Do not loosen or remove the cap to cool an over-
heated 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.
Coolant Level
The coolant bottle provides a quick visual method for
determining that the coolant level is adequate. The
coolant level must be at the FULL mark or above the
ADD mark on the bottle.
The radiator normally remains completely full, so there is
not need to remove the radiator cap unless checking for
coolant freeze point or replacing coolant. Advise your
MAINTAINING YOUR VEHICLE 241
7

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 coolant is needed to maintain 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 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 bottle.
²Check coolant freeze point in the system.
²If frequent coolant additions are required, or if the
level in the recovery bottle does not drop when the
engine cools, the cooling system should be pressure
tested for leaks.
²Maintain coolant concentration at 50% ethylene glycol
antifreeze (minimum) in water for proper corrosion
protection of your engine that contains aluminum
components.
²Make sure that the radiator and coolant bottle hoses
are not kinked or obstructed.
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.
242 MAINTAINING YOUR VEHICLE

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.
Brake System
In order to assure brake system performance, all brake
system components should be inspected periodically.
Refer to the appropriate ªMaintenance Scheduleº 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:Inspection of brake hoses should be done
whenever the brake system is serviced and every engine
oil change.
MAINTAINING YOUR VEHICLE 243
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