Lumina V6-191 3.1L (1990)
Parking Brake Cable: Customer Interest
Vehicle - Diagnosing Underbody Noise From Rear
Number:
90-113-3D
Section:
3D
Date:
December 1989
Corporate Bulletin No:
933404
Subject:
REAR UNDERBODY NOISE DIAGNOSIS
Model and Year:
1990 W CAR
TO:
ALL CHEVROLET DEALERS
Some 1990 W-cars may exhibit various noises emanating from the rear of the vehicle that may be caused by a variety of conditions in the rear
suspension, exhaust, fuel or park brake cable systems.
It is the intent of this bulletin to summarize prior issued bulletins and provide insight into other conditions that have been noted to aid in the proper
diagnosing of customer noise comments.
When prior published bulletins are referenced, they should be utilized to insure proper service procedures are followed.
SQUEAK/SQUAWK NOISE
Condition:
Squeaking during normal suspension/vehicle operation.
Cause:
Park brake cable movement through grommet in cable support brackets.
Correction:
Apply lubricant to cables in area of grommets. Reference Dealer Service Bulletin No. 90-90-5, dated November 1989.
Condition:
Squawking during normal vehicle operation and most prevalent in cold or wet weather.
Cause:
Auxiliary spring rubbing against edge of spring mounting bracket.
Correction:
Remove auxiliary spring per procedure outlined in Service Manual and reinstall with clearance to edge of mounting brackets.
CLUNK NOISE
Condition:
Clunk noted during normal suspension/vehicle movements.
Cause:
Exhaust system contacting rear stabilizer bar.
Correction:
Inspect exhaust system and stabilizer bar for witness marks due to metal to metal contact. Align exhaust system to provide
adequate clearance if interference condition is noted.
RATTLE NOISE
Condition:
Metallic rattling during normal vehicle operation or engine run up in neutral.
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:
Dull rattling noted during normal suspension/vehicle operation.
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 Dealer Service Bulletin No. 90-90-5,
dated November 1989.
Condition:
Metallic rattling noted during engine run-up in neutral or normal suspension/vehicle operation.
Cause:
Loose exhaust system heat shields.
Correction:
Inspect and tighten loose exhaust system heat shield fasteners insuring sufficient clearance is maintained.
