For 1990-2009 cars

# 3.8L V-6 GOODWRENCH ENGINE P/N'S AND MAJOR DIFFERENCES

BULLETIN 86-T-26 ADVISED THAT ENGINE PART NUMBER 25528795 REPLACED ENGINE 25525217. THESE ENGINES ARE FOR REAR WHEEL DRIVE CARBURETED ENGINES ONLY. THEY CANNOT BE USED IN A TRANSVERSE ENGINE APPLICATION. IT IS ESSENTIAL THAT YOU REFER TO THE PARTS MANUAL FOR PROPER APPLICATION. PART NUMBER 25528795 GENERAL MOTORS PARTS RECENTLY RELEASED THE ABOVE GOODWRENCH ENGINE FOR 1986 AND PRIOR MODEL YEAR USGAGE. THERE ARE, HOWEVER, SOME MAJOR DIFFERENCES THAT SHOULD BE NOTED PREVIOUS YEAR APPLICATIONS AND THEY ARE AS FOLLOWS: - CYLINDER HEAD GASKET - A NEW, THICKER GASKET IS BEING USED THIS YEAR. IT HAS A GRAPHITE MATERIAL LAMINATED OVER STEEL. THIS GASKET SHOULD IMPROVE CYLINDER HEAD TO BLOCK SEALING. - CYLINDER BLOCK - IN ORDER TO ACCOMODATE THE NEW CYLINDER HEAD GASKET, THE BLOCK DECK HEIGHT HAS BEEN LOWERED APPROXIMATELY .038 OF AN INCH. IN ORDER TO EASE IDENTIFICATION OF THE GOODWRENCH BLOCK, "6GW" WILL BE STAMPED NEXT TO THE THREE DIGIT JULIAN DATE ON THE FRONT FACE OF THE BLOCK. - CYLINDER HEAD BOLTS - ALSO NEW ARE THE CYLINDER HEAD BOLTS. THESE ARE DESIGNED TO IMPROVE CLAMPING OF THE HEADS TO THE BLOCK. - PISTON RING EXPANDER - A NEW, LOW TENSION EXPANDER IS USED IN THIS YEAR'S ENGINE. THIS SHOULD REDUCE INTERNAL ENGINE FRICTION. THE CRITICAL NATURE OF THE CHANGES TO THE CYLINDER HEAD AREA MAKE IT ABSOLUTELY NECESSARY THAT THE CYLINDER HEAD SERVICE LABEL BE INSTALLED PER THE INSTRUCTIONS PROVIDED WITH THE ENGINE. FAILURE TO DO THIS MAY RESULT IN INCORRECT PARTS OR SERVICE PROCEDURES BEING USED IF THE CAR IS SERVICED LATER. THIS, IN TURN, MAY RESULT IN CUSTOMER DISSATISFACTION WITH THE ENGINE YOU INSTALLED AND A CUSTOMER COMEBACK. THIS INFORMATION SHOULD BE CONVEYED TO ALL DEALERSHIP TECHNICIANS WHO MIGHT BE INVOLVED IN THE INSTALLATION OF ONE OF THESE UNITS, OR REQUIRED TO WORK ON IT AT A LATER DATE.

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.