Exhaust - Information On Rattle/Ringing Noise

9214pontiac01

Bulletin Number: 92-6-37
Reference Number: 236603
Publish Date: 3/92


Subject: INFORMATION ON EXHAUST
RATTLE/RINGING NOISE

Models
Affected: 1991-92 GRAND PRIX MODELS
WITH 3.4L V-6 ENGINE (RPO LQ1)


This bulletin provides information regarding a potential customer concern of an audible noise condition that may be perceived as a metallic rattle/ringing on some 1991-92 Grand Prix models with 3.4L V-6 engines (RPO LQ1).

Condition:

An audible metallic rattle/ringing type noise that appears to be coming from the rear underbody area of the vehicle, evident during vehicle warm-up after cold start.

Cause:

Combination of the engine fuel/air ratio prior to reaching normal operating temperature and unequal length exhaust takedown pipes, generate exhaust pulses that create a resonance in the exhaust system.

Do not attempt any modifications or repairs to the engine and/or exhaust system to correct this condition.

This information is being conveyed to keep car dealers and customers informed and to alleviate any unnecessary repairs.

When repair information becomes available, this bulletin will be updated.