For 1990-2009 cars

# SERPENTINE BELT NOISE OR VIBRATION-INSTALL IDLER PULLEY

SERPENTINE DRIVE SYSTEM NOISE

#### VEHICLES AFFECTED: 1987 2.8L F CARS WITH 2.8L PFI ENGINE (VIN CODE W)

Some 1987 Chevrolet Camaros and/or Pontiac Firebirds, with automatic transmission, air conditioning and 2.8L multi-port fuel injection engine may exhibit a growl and/or vibration from the serpentine drive system. This noise or vibration condition results from belt flutter and is due to the long belt span which exists between the generator and crankshaft pulleys.

If customer comments are received concerning accessory drive system noise or objectionable vibration, an idler pulley should be incorporated into the accessory drive system. The hardware and instructions for installing the idler pulley system may be obtained by ordering service package, P/N 10099902 from General Motors Service Parts.

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.