For 1990-2009 cars

# HEAD BOLT BREAKAGE POSSIBLE INCORRECT BOLTS

#### VEHICLES AFFECTED: 1984 'B-D-E' Series Vehicles Equipped With 5.0L V8 Gas Engines (VIN Code Y, 9)

A limited number of 1984 5.0L V-8 gas engines may have been built with head bolts which may vary in hardness. The bolts are from one of the batches of bolts marked 'F' on the bolt head. See Fig. 1. If an instance of head bolt breakage is encountered, head bolts marked 'F' on the bolt head should be replaced in that engine, as well as the head gaskets.

Bolts marked 'F' from Dealer stock, WDDGM, or in an engine where bolt breakage has not occurred should be considered usable bolts.

Part No. 22510580 for short bolts and Part No. 22510579 for long bolts are 5.7L diesel head bolts, which may be used in the 5.0L gas engine when replacement bolts are required.

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.