NEW DESIGN CYL. HEAD GASKETS 90 DEGREE 'V' ENGINES

MODELS: 1987 AND PAST MODEL YEAR TRUCKS AND EARLY PRODUCTION 1988 C/K MODEL TRUCKS EQUIPPED WITH 4.3L, 5.OL AND 5.7L ENGINES

An improved cylinder head gasket of composite construction has been released to replace the metal gasket. The new gasket has improved sealing capabilities. The new part numbers shown below should be used for service.

Application Cylinder Head Gasket ----------- -------------------- 4.3L Truck 10066080 5.OL Truck 10066081 5.7L Truck 10066082

Engines manufactured after the following build date codes were built with the new composite gasket.

Engine Engine Build Date Date Codes ------ ---------- ---------- 4.3L May 15,1987 T0515XXX 5.OL July 1, 1987 V07OIXXX K07OIXXX 5.7L July 1, 1987 V0701XXX K0701XXX

Engine date codes are stamped on a pad at the block to passenger side cylinder head parting line, see Figure No. 1. The build date codes may be found in this area and appear as shown in the following example:

T1202ABC

The first letter indicates the plant where the engine was manufactured, the next four numbers indicate the date of manufacture, in this case, 12th month 2nd day, and the last three digits may be any broadcast code.

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.