CATALYTIC CONVERTER RATTLE NOISE

VEHICLES AFFECTED: 1985-87 R CAR

THIS BULLETIN HAS BEEN REVISED TO CORRECT THE PART NUMBERS LISTED FOR THE 1985 AND 1987 CATALYTIC CONVERTER.

Some of the subject vehicles may exhibit a rattle noise from the catalytic converter. This condition can be caused by insufficient thermal expansion of the substrate retaining mat internal to the converter. Vehicles that are primarily used for short journeys may exhibit this condition as the internal temperature of the converter does not reach the level required to cause expansion of the mat.

New parts have been made available through GMSPO which provide retention of the substrate independent of the mat expansion.

Vehicles exhibiting the described condition should have the converter replaced by the part number listed below appropriate to the model year of the vehicle.

* 1985 - P/N 25104654 Catalytic Converter

1986 - P/N 25104651 Catalytic Converter

* 1987 - P/N 25127472 Catalytic Converter

Replacement should be carried out following the appropriate service manual procedures.

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.