GM Service Manual Online
For 1990-2009 cars only

EXHAUST NOISE 4.3L HO NEW EXHAUST ASSY. RELEASED

SUBJECT: EXHAUST NOISE

MODELS: 1990-91 M VANS with 4.3L (LU2) HI-OUTPUT ENGINE (VIN CODE B)

Some owners of 1990-91 M vans equipped with the 4.3L (LU2) Hi-Output engine may comment about a high level of exhaust noise during a variety of driving conditions.

If this condition is encountered, and there are no leaks found in the exhaust system, a newly released, quieter muffler/exhaust assembly (P/N 15650877) may be installed. This new assembly consists of a one piece exhaust pipe, muffler and tailpipe.

VEHICLES INVOLVED

Vehicles built after the following VIN breakpoint were manufactured with this quieter exhaust system.

1991 GMC 1GKDM19B4MB509183

SERVICE PARTS INFORMATION

Part Number Description ----------- ---------------- 15650877 muffler assembly

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty use: Labor Operation: L2584 Labor Time: 0.5 hr.

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.