(C) Rattle Noise

(C) RATTLE NOISE

CONDITION: I
Metallic rattling during normal vehicle operation or engine run up in neutral (1988-90 vehicles).

CAUSE:
Loose clinch nuts in either exhaust intermediate pipe or underbody hanger brackets.

CORRECTION:
Install washer P/N 11500367 between hanger and either or both the underbody and pipe brackets.


CONDITION: II
Metallic rattling noted during engine run-up in neutral or normal suspension/vehicle operation. (1988-90 vehicles).

CAUSE:
Loose exhaust system heat shields.

CORRECTION:
Inspect and tighten loose exhaust system heat shield fasteners insuring sufficient clearance is maintained.


CONDITION: III
Dull rattling from rear of vehicle noted during normal suspension/vehicle operation (1988-90 vehicles)

CAUSE:
Park brake cable grommets not properly installed in underbody retaining brackets.

CORRECTION:
Insure both underbody brackets are not distorted and install cable grommets (Reference Bulletin # 90-5-4).


CONDITION: IV
Light hammering/rattle type noise from front of vehicle after a cold start at low ambient temperatures on 1988 vehicles assembled prior to VIN J1452620.

CAUSE:
Pressure pulsations in the fuel system generated by fuel injector operation, resulting in hydraulic hammering in chassis fuel pipes.

CORRECTION:
Install new underhood fuel return hose and stand-pipe assembly, P/N 10114735, (Reference Bulletin # 88-6C-4).