For 1990-2009 cars

# SPARK PLUG HOLE THREAD DAMAGE SPARK PLUG RECESS RETENTION

#### VEHICLES AFFECTED: 1987 'J-L AND Y' CARS WITH LL8 (VIN CODE 1) L-4 ENGINES, LT3 (VIN CODE M) OHC-4 ENGINES, LT2 (VIN CODE K) OHC-4 ENGINES, LB6 (VIN CODE W) V6 ENGINES, AND L98 (VIN CODE B) V8 ENGINES

Contamination in the spark plug recess is not a new concern for any engine. However, for the above engines with aluminum heads, this collected debris could cause spark plug hole thread damage.

Continued good service practice of dirt removal for this engine, as well as others, during spark plug removal and installation should be maintained. This "extra care" will lessen any unnecessary followup engine repairs and hence eliminate dissatisfied customers.

This bulletin is for information only.

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.