EXHAUST SYSTEM MOAN NOISE (REVISED INTERMEDIATE HANGER)

SUBJECT: EXHAUST MOAN NOISE (REVISED INTERMEDIATE EXHAUST HANGER)

VEHICLES AFFECTED: 1992 PONTIAC N-CAR 1992 BUICK N-CAR 1992 OLDSMOBILE N-CAR WITH 3300 ENGINE (VIN CODE N)

Condition:

--------- Some 1992 N cars may exhibit a "moan" type noise which may be heard throughout the passenger compartment of the vehicle. This noise is especially heard in the 2400 - 2500 engine RPM range.

Cause:

----- The intermediate exhaust pipe hanger may not be properly isolating the exhaust systems vibrations at these engine speeds.

Correction:

---------- Starting in early January, Production vehicles were being assembled with a revised style intermediate exhaust hanger. The revised hanger may reduce the amount of vibrations which could cause a "moan" type noise. The revised hanger may be used for service when addressing customer's concerns.

Early production vehicles before the following VIN breakpoints have the original style of intermediate exhaust hanger which may require the revised hanger:

Division VIN Breakpoint -------- -------------- Buick NC626474 Oldsmobile NM407650 Pontiac NC221040 (Lansing South Plant - "C") NM040997 (Lansing North Plant - "M")

Procedure:

--------- 1. Raise vehicle.

2. Remove original intermediate exhaust hanger.

3. Install revised hanger P/N 22577467 (Tighten to 27 N.m or 20 ft.lbs.)

4. Lower vehicle.

For vehicles repaired under warranty use:

Labour Operation Number: L2020 Labour Time: 0.3 Hour

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.