Jeep XJ. Manual — part 77
• Holds Steady: If the pointer remains steady for
two minutes, there are no serious coolant leaks in
the system. However, there could be an internal leak
that does not appear with normal system test pres-
sure. Inspect for interior leakage or do the Internal
Leakage Test. Do this if it is certain that coolant is
being lost and no leaks can be detected.
• Drops Slowly: Shows a small leak or seepage is
occurring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect the radiator,
hoses, gasket edges and heater. Seal any small leak
holes with a Sealer Lubricant or equivalent. Repair
leak holes and reinspect the system with pressure
applied.
• Drops Quickly: Shows that a serious leakage is
occurring. Examine the system for serious external
leakage. If no leaks are visible, inspect for internal
leakage. Large radiator leak holes should be repaired
by a reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove the oil pan drain-plug and drain a small
amount of engine oil. Coolant, being heavier will
drain first, or operate engine to churn oil, then exam-
ine dipstick for water globules. Operate the engine
without the pressure/vent cap on the coolant tank
until thermostat opens.
Attach a radiator pressure tester to the tank filler
neck. If pressure builds up quickly, a leak exists as
result of a faulty cylinder head gasket or crack in the
engine. Repair as necessary.
WARNING: DO
NOT
ALLOW
PRESSURE
TO
EXCEED 117 KPA (17 PSI). TURN THE ENGINE OFF.
TO RELEASE THE PRESSURE, ROCK THE TESTER
FROM SIDE TO SIDE. WHEN REMOVING THE
TESTER, DO NOT TURN THE TESTER MORE THAN
1/2 TURN IF THE SYSTEM IS UNDER PRESSURE.
If there is no immediate pressure increase, pump
the pressure tester until the indicated pressure is
within the system range. Vibration of the gauge
pointer indicates compression or combustion leakage
into the cooling system.
PRESSURE/VENT CAP
PRESSURE TESTING
Remove the cap from the coolant tank. Be sure
that sealing surfaces are clean. Moisten rubber gas-
ket with water.
A two-piece, threaded adapter set (Fig. 11) must be
used to adapt a standard pressure-type tester (Fig.
12) when testing either the coolant tank or pressure
cap.
Use
Kent-Moore
t
adapter
set
number
J-24460-92 or Snap-On
t numbers TA-32 and TA-33.
Attach the adapter to the cap. Adapter must first be
threaded to cap. Attach pressure tester to adapter.
Operate the tester pump and observe the gauge
pointer at its highest point. The cap release pressure
should be 90-to-117 kPa (13-to-17 psi). The cap is sat-
isfactory when the pressure holds steady. It is also
good if it holds pressure within the 90-to-117 kPa
(13-to-17 psi) range for 30 seconds or more. If the
pointer drops quickly, replace the cap.
CAUTION: Radiator pressure testing tools are very
sensitive to small air leaks, which will not cause
cooling system problems. A pressure cap that does
not have a history of coolant loss should not be
replaced just because it leaks slowly when tested
with this tool. Add water to tool. Turn tool upside
down and recheck pressure/vent cap to confirm
that cap needs replacement.
LOW COOLANT LEVEL- AERATION
CAUTION: Engine damage could occur if the cool-
ant level is allowed to get this low. Always ensure
that the coolant level is not below the full mark. For
better visibility of the coolant level use a shop lamp
to light the pressurized coolant tank and look
through the pressurized coolant tank.
Fig. 12 Typical Cooling System Pressure Tester
1 – PRESSURE CAP
2 – TYPICAL COOLING SYSTEM PRESSURE TESTER
7 - 16
COOLING SYSTEM
XJ
DIAGNOSIS AND TESTING (Continued)
2000 JEEP CHEROKEE
BELT DIAGNOSIS
When diagnosing serpentine accessory drive belts,
small cracks that run across the ribbed surface of the
belt from rib to rib (Fig. 13), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) are not nor-
mal. Any belt with cracks running along a rib must
be replaced (Fig. 13). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
Refer to the Serpentine Drive Belt Diagnosis chart
for further belt diagnosis.
CONDITION
POSSIBLE CAUSES
CORRECTION
RIB CHUNKING (ONE OR MORE
RIBS HAS SEPARATED FROM
BELT BODY
1. Foreign objects imbedded in
pulley grooves.
1. Remove foreign objects from
pulley grooves. Replace belt.
2. Installation damage.
2. Replace belt.
RIB OR BELT WEAR
1. Pulley(s) misaligned.
1. Align pulley(s).
2. Abrasive environment.
2. Clean pulley(s). Replace belt if
necessary.
3. Rusted pulley(s).
3. Clean rust from pulley(s).
4. Sharp or jagged pulley groove
tips.
4. Replace pulley.
5. Rubber deteriorated.
5. Replace belt.
LONGITUDINAL BELT CRACKING
(CRACKS BETWEEN TWO RIBS)
1. Belt has mistracked from pulley
groove.
1. Replace belt.
2. Pulley groove tip has worn away
rubber to tensile member
2. Replace belt.
Fig. 13 Serpentine Belt Wear Patterns
1 – NORMAL CRACKS BELT OK
2 – NOT NORMAL CRACKS RELACE BELT
XJ
COOLING SYSTEM
7 - 17
DIAGNOSIS AND TESTING (Continued)
2000 JEEP CHEROKEE
CONDITION
POSSIBLE CAUSES
CORRECTION
BELT SLIPS
1. Belt slipping because of
insufficient tension.
1. Replace automatic belt tensioner.
2. Incorrect belt.
2. Replace belt.
3. Belt or pulley subjected to
substance (belt dressing, oil,
ethylene glycol) that has reduced
friction.
3. Replace belt and clean pulleys.
4. Driven component bearing
failure.
4. Replace faulty component
bearing.
5. Belt glazed and hardened from
heat and exessive slippage.
5. Replace belt.
88
GROOVE JUMPING” (BELT
DOES NOT MAINTAIN CORRECT
POSITION ON PULLEY)
1. Belt tension either too high or too
low.
1. Replace automatic belt tensioner.
2. Incorrect belt.
2. Replace belt.
3. Pulley(s) not within design
tolerance.
Replace pulley(s).
4. Foreign object(s) in grooves.
4 Remove foreign objects from
grooves.
4. Pulley misalignment.
4. Check and replace.
5. Belt cordline is broken.
5. Replace belt.
BELT BROKEN (NOTE: IDENTIFY
AND CORRECT PROBLEM
BEFORE NEW BELT IS
INSTALLED)
1. Excessive tension.
1. Replace belt and automatic belt
tensioner.
2. Incorrect belt.
2. Replace belt.
3. Tensile member damaged during
belt installation.
3. Replace belt.
4. Severe misalignment.
4. Check and replace.
5. Bracket, pulley, or bearing
failure.
5. Replace defective component
and belt.
NOISE (OBJECTIONAL SQUEAL,
SQUEAK, OR RUMBLE IS HEARD
OR FELT WHILE DRIVE BELT IS
IN OPERATION)
1. Belt slippage.
1. Replace belt or automatic belt
tensioner.
2. Bearing noise.
2. Locate and repair.
3. Belt misalignment.
3. Replace belt.
4. Belt-to-pulley mismatch.
4. Install correct belt.
SERPENTINE DRIVE BELT DIAGNOSIS
SERVICE PROCEDURES
COOLANT LEVEL CHECK
The coolant level is checked and adjusted at the
pressurized coolant tank (Fig. 14). The tank is
located at the right-rear side of the engine compart-
ment and is mounted as the highest point of the cool-
ing system. This will allow any air or vapor
exceeding the pressure/vent cap rating to escape
through the cap. The coolant tank is equipped with a
threaded-on pressure/vent cap. Refer to Pressure/
Vent Cap for additional information.
A coolant reserve/overflow system with a separate
tank is not used with the 2.5L diesel engine.
NOTE: The coolant level should be checked after
the engine has been operated at normal operating
temperature for approximately 5–10 minutes.
(1) Add coolant into the coolant tank up to the
FULL mark. If possible, only add coolant when
the engine is cold. Coolant level in a warm
7 - 18
COOLING SYSTEM
XJ
DIAGNOSIS AND TESTING (Continued)
2000 JEEP CHEROKEE
engine will be higher in the tank due to ther-
mal expansion.
(2) After the engine has been operated through a
few heat-up and cool-down cycles, recheck the coolant
level in the tank.
DRAINING COOLING SYSTEM
The cooling system is equipped with a pressurized
coolant tank using a pressure/vent cap.
WARNING: DO
NOT
REMOVE
THE
CYLINDER
BLOCK DRAIN-PLUG, THE COOLANT TANK CAP,
THE RADIATOR FILL VENT VALVE, OR LOOSEN
THE RADIATOR DRAINCOCK WITH THE SYSTEM
HOT AND PRESSURIZED. SERIOUS BURNS FROM
THE COOLANT CAN OCCUR.
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,
WAIT AT LEAST 15 MINUTES BEFORE REMOVING
COOLANT TANK CAP. WITH A RAG, SQUEEZE THE
UPPER RADIATOR HOSE TO CHECK IF SYSTEM IS
UNDER PRESSURE. PLACE A RAG OVER THE CAP.
VERY
SLOWLY
ROTATE
THE
CAP
COUNTER-
CLOCKWISE ALLOWING PRESSURE TO SLOWLY
RELEASE. AFTER ALL PRESSURE
HAS
BEEN
RELEASED, REMOVE THE COOLANT TANK CAP
COMPLETELY.
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
(1) Observe the previous WARNINGS and remove
the coolant tank pressure/vent cap.
(2) The plastic radiator draincock is located on the
bottom of the left radiator tank. It can be accessed by
removing the left front headlamp bezel and the radi-
ator grille assembly from the bottom of vehicle.
(a) Attach one end of a 24 inch long X 1/4 inch
ID drain-hose to the nipple below the radiator
draincock.
(b) Put the other end of drain-hose into a clean
container.
(c) Open
the
draincock
(counterclockwise
as
viewed from left side of vehicle) and drain coolant
from radiator.
(3) If the complete cooling system must be drained,
raise the vehicle and remove the cylinder block
drain-plug. This hex- headed plug is located on the
right/rear side of the engine above the starter motor.
REFILLING COOLING SYSTEM
The cooling system is equipped with a pressurized
coolant tank using a pressure/vent cap. Refilling of
the system is done through this tank.
NOTE:
The radiator draincock is equipped with a
rubber o-ring. Do not over tighten draincock.
(1) Tighten
the
radiator
draincock
and
(if
removed), the cylinder block drain-plug.
(2) Open
the
plastic
radiator
fill
vent
valve
(unscrews counter- clockwise) from the radiator. The
fill vent valve is located on the top of the right radi-
ator tank.
(3) With the fill vent valve open, proceed to fill the
system using a 50/50 mixture of water and antifreeze
as described in the Coolant section of this group.
(4) Continue to fill the cooling system until coolant
is observed escaping from the fill vent opening. When
this occurs, close the fill vent valve. The plastic fill
vent valve is equipped with a rubber o- ring. Do
not over tighten the fill vent valve.
(5) Continue to fill the system until the coolant
tank is full.
(6) Install and tighten the coolant tank pressure/
vent cap. Do not use any type of tool when tight-
ening the cap. Hand tighten only.
(7) Operate engine with coolant tank cap tight-
ened.
(8) After engine has reached normal operating
temperature, shut engine off and allow it to cool.
(9) Remove coolant tank cap.
(10) Add coolant into the coolant tank up to the
FULL mark. If possible, only add coolant when
the engine is cold. Coolant level in a warm
engine will be higher in the tank due to ther-
mal expansion.
(11) After the engine has been operated through a
few heat-up and cool-down cycles, recheck the coolant
level in the tank.
Fig. 14 Coolant Tank and Pressure/Vent Cap
1 – PRESSURE/VENT CAP
2 – PRESSURIZED COOLANT TANK
3 – LOW COOLANT LEVEL SENSOR
XJ
COOLING SYSTEM
7 - 19
SERVICE PROCEDURES (Continued)
2000 JEEP CHEROKEE
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст