GM Service Manual Online
For 1990-2009 cars only

NEW 1986 3.0L & 3.8L ENGINES PARTS NOT INTERCHANGABLE

VEHICLES AFFECTED: All Models Equipped with 1986 3.OL (VIN Code L) Or 3.8L (VIN Codes B, 3 & 7) SFI V-6 Engines

The 1986 Model 3.OL (VIN Code L) and 3.8L (VIN Codes A, B, 3 & 7) V-6 engines look very much like the 1985 version, however, changes have been incorporated in the 1986 model that prohibit interchangeability of numerous parts or assemblies between the two units. Some examples of the differences are: block deck height at the cylinder head surface has been lowered .965 mm (.038 in.); composition head gaskets are used; new torque to yield head bolts; and 5 mm injectors vs. 4 mm for some applications, etc.

Attempts to interchange any of these parts, that are not identified as compatible in the Parts Catalogue, could create anything from a driveability problem to an inability to reassemble the unit correctly.

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.