GM Service Manual Online
For 1990-2009 cars only

NEW THERMOSTAT GASKET MAY REPAIR HEATER COMPLAINTS

THIS BULLETIN HAS BEEN REVISED TO INCLUDE 1989 MODELS, AND TO UPDATE PART NUMBER OF SEALING GASKET.

NOTICE: THIS BULLETIN SUPERSEDES CORPORATE BULLETIN 806202R, 88-6-10 DATED MARCH, 1988, DUE TO A CHANGE IN PRODUCTION DESIGN. PLEASE DISCARD 88-6-10 AND REPLACE IT WITH THIS REVISION.

AT THE START OF 1989 PRODUCTION, ALL 3800 ENGINES WILL BE ASSEMBLED WITH A NEW RUBBER THERMOSTAT GASKET. THIS GASKET IS ASSEMBLED ON THE TOP SIDE OF THE THERMOSTAT AND PROVIDES A SEAL TO THE COOLANT OUTLET. THE PREVIOUS PAPER GASKET, PART NUMBER 25534927, SHOULD NOT BE USED AND REPLACED WITH THE NEW THERMOSTAT SEALING GASKET, PART NUMBER 25535939.

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

NOTICE: THE INSIDE DIAMETER OF THE NEW GASKET IS CONICAL IN SHAPE AND SHOULD BE INSTALLED ON THE THERMOSTAT AS INDICATED IN FIGURE 1. REMOVE AND DISCARD OLD STYLE PAPER GASKET, IF USED ON 1988 MODELS, PRIOR TO INSTALLING NEW RUBBER GASKET. FIGURES: 0

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.