DIAGNOSIS OF NOISE FROM REAR MAIN SEAL

MODELS AFFECTED: 1987 SKYHAWKS WITH THE LL8 2.OL L-4 ENGINE VIN CODE 1)

Reports have been received of rear main seals being replaced because of a "chirping" or "squealing" noise that goes away when an oil is sprayed into that area. However, improper engine ventilation can produce an internal vacuum depression which draws air past the seal.

If the noise symptom disappears when the oil dipstick is removed (preventing internal vacuum depression), check the fresh air feed hole in the air inlet rubber duct for blockage where it connects to the metal pipe going to the rocker cover. Cut out any blockage to eliminate the noise problem and the need for rear seal replacement.

WARRANTY INFORMATION

Labor Operation Number: T1224 Labor Time: .3 Hour Trouble Code: 92

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.