INFORMATION ON ENGINE BLOCK HEATER APPLICATION

SUBJECT: INFORMATION ON ENGINE BLOCK HEATERS

MODELS AFFECTED: ALL 1982-1994 CADILLACS WITH 4.1L, 4.5L, 4.9L V8 ENGINE

Beginning with model year 1987, 4.1L V8 engines received a structural redesign to the engine crankcase which prevents the 1982 through 1986 clamp-on engine block heater from being used. Consequently a revised block heater was released.

As these engines have now been subject to remanufacturing, situations may arise where the revised crankcase is used to produce a 1982-1986 application. Figure 1 shows the 1982-1986 version, and by comparison with Figure 2 it can be seen that each crankcase requires a specific heater design. When conditions arise where the ribbed crankcase is used in a pre- 1987 vehicle with the engine block heater option, a new heater assembly (P/N 1642788) must be purchased.

Both block heater kits are currently available from GMSPO.

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.