Jeep 1997 Grand Cherokee Service Manual page 239

ZG
DIAGNOSIS AND TESTING (Continued)
SERPENTINE DRIVE BELT DIAGNOSIS–4.0L 6-CYLINDER ENGINE
CONDITION
RIB CHUNKING (ONE OR MORE RIBS
HAS SEPARATED FROM BELT BODY)
RIB OR BELT WEAR
LONGITUDINAL BELT CRACKING
(CRACKS BETWEEN TWO RIBS)
BELT SLIPS
"GROOVE JUMPING" (BELT DOES NOT
MAINTAIN CORRECT POSITION ON
PULLEY)
BELT BROKEN (NOTE: IDENTIFY AND
CORRECT PROBLEM BEFORE NEW
BELT IS INSTALLED)
NOISE (OBJECTIONAL SQUEAL,
SQUEAK, OR RUMBLE IS HEARD OR
FELT WHILE DRIVE BELT IS IN
OPERATION)
TENSION SHEETING FABRIC FAILURE
(WOVEN FABRIC ON OUTSIDE,
CIRCUMFERENCE OF BELT HAS
CRACKED OR SEPERATED FROM
BODY OF BELT)
CORD EDGE FAILURE (TENSILE
MEMBER EXPOSED AT EDGES OF
BELT OR SEPERATED FROM BELT
BODY)
POSSIBLE CAUSES
1. Foreign objects imbedded in
pulley grooves.
2. Installation damage.
1. Pulley(s) misaligned.
2. Abrasive environment.
3. Rusted pulley(s).
4. Sharp or jagged pulley groove
tips.
5. Rubber deteriorated.
1. Belt has mistracked from pulley
groove.
2. Pulley groove tip has worn away
rubber to tensile member.
1. Belt slipping because of
insufficient tension.
2. Belt or pulley subjected to
substance (belt dressing, oil ethylene
glycol) that has reduced friction.
3. Driven component bearing failure.
4. Belt glazed and hardened from
heat and excessive slippage.
1. Belt tension either too high or too
low.
2. Pulley(s) not within design
tolerance.
3. Foreign object(s) in grooves.
4. Pulley misalignment.
5. Belt cordline is broken.
1. Excessive tension.
2. Tensile member damaged during
belt instalation.
3. Severe misalignment.
4. Bracket, pulley, or bearing failure.
1. Belt slippage.
2. Bearing noise.
3. Belt misalignment.
4. Belt-to-pulley mismatch.
5. Driven component induced
vibration
6. System resonant frequency
induced vibration.
1. Tension sheeting contacting
stationary object.
2. Excessive heat causing woven
fabric to age.
3. Tension sheeting splice has
fractured.
1. Excessive tension.
2. Belt contacting stationary object.
3. Pulley(s) out of tolerance.
4. Insufficient adhesion between
tensile member and rubber matrix.
COOLING SYSTEM
POSSIBLE CAUSES
1. Remove foreign objects from pulley
grooves. Replace belt.
2. Replace belt.
1. Align pulley(s).
2. Clean pulley(s). Replace belt if
necessary.
3. Clean rust from pulley(s).
4. Replace pulley.
5. Replace belt.
1. Repace belt.
2. Replace belt.
1. Replace automatic belt tensioner.
2. Replace belt and clean pulleys.
3. Replace faulty component bearing.
4. Replace belt.
1. Adjust belt tension.
2. Replace pulley(s).
3. Remove foreign objectsfrom grooves.
4. Align component.
5. Replace belt.
1. Replace belt and adjust tension to
specification.
2. Replace belt.
3. Align pulley(s).
4. Replace defective component and belt.
1. Adjust belt.
2. Locate and repair.
3. Replace belt/pulley(s).
4. Install correct belt.
5.Locate defective driven component and
repair.
6.Vary belt tension within specifications.
Replace belt.
1. Correct rubbing condition.
2. Replace belt.
3. Replace belt.
1. Adjust belt tension.
2. Correct as necessary.
3. Replace pulley.
4. Replace belt and adjust tension to
specifications.
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