Chrysler 1991 Service Manual Supplement page 68

•
5.9L (DIESEL) ENGINES 9 - 5
SERVICE DIAGNOSIS • MECHANICAL (CONT.)
CONDITION POSSIBLE CAUSES
CORRECTION
EXCESSIVE VIBRATION Loose or broken engine mounts. Replace engine mounts.
Damaged fan or improperly
operating accessories.
Check and replace the vibrating components.
Improperly operating vibration
damper.
Inspect/replace the vibration damper.
Improperly operating fan hub. Inspect/replace the fan hub.
Worn or damaged alternator
bearing.
Check/replace the alternator.
Flywheel housing misaligned. Check/correct flywheel alignment.
Loose or broken power
component.
Inspect the crankshaft and rods for damage that causes an
unbalance. Repair/replace as required.
Worn or unbalanced driveline
components.
Check/repair driveline components.
EXCESSIVE ENGINE
NOISES
Drive belt squeal, insufficient
tension or abnormally high
loading.
Check the tensioner and inspect the drive belt. Make sure water
pump, tensioner pulley, fan hub and alternator turn freely.
Intake air or exhaust leaks. Refer to Excessive Exhaust Smoke (Engine Diagnosis—
Performance).
Excessive valve lash Adjust valves. Make sure the push rods are not bent and rocker
levers or adjusting screws are not severely worn. Replace bent
or severely worn pads.
Turbocharger noise. Check turbocharger impeller and turbine wheel for housing
contact. Repair/replace as required.
Gear train noise. Visually inspect and measure gear backlash. Replace gears as
required.
Power function knock. Check/replace rod and main bearings.
ALTERNATOR NOT
CHARGING OR IN-
SUFFICIENT CHARGING
Loose or corroded battery
connections.
Alternator belt slipping.
Clean/tighten battery connection.
Check/replace belt tensioner. Check/replace belt.
Alternator pulley loose on
shaft.
Tighten pulley.
Improperly operating
alternator.
Check/replace alternator.
J9109-253