CYLINDER HEAD GASKET FAILURES CHECK COOLANT SYSTEM

VEHICLES AFFECTED: 1982-86 1.8L OHC 'J' MODEL L4 ENGINE (VIN CODE O)

Some cylinder head gaskets are being replaced on 1982 thru 1986 I.BL OHC engines. Investigation has determined that the cause of this failure may be an engine coolant system related condition. Specifically, some cylinder head gasket failures have been accompanied by failed coolant temperature sensors or failed coolant fan switches. Either of these conditions could expose the cylinder head gasket to excessive temperatures and thermal stresses.

The 1.8L OHC turbo cylinder head gasket, P/N 90200347, has been designed to accomodate higher stress levels and is less susceptible to the type of failures being encountered, and is recommended as the service replacement.

It is recommended that the cooling system temperature sensor and fan switch (section 8A, Shop Manual) be checked to insure proper function.

It is essential that the engine be started and run until the thermostat opens. Torque all cylinder head / cam carrier bolts an additional 30 - 50 degrees in sequence as shown in the shop manual, section 6A.

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.