ALUMINUM HEAD ENGINE SPARK PLUG SERVICE PROCEDURE

Model and Year: 1986 CORVETTE 5.7L PFI L98 -------------- (VIN CODE 8) ENGINE

TO: ALL CHEVROLET DEALERS

Removing spark plugs from 5.7L PFI engines with aluminum heads for inspection, servicing or replacement is a relatively simple task, but it does require care and attention.

NOTICE: To remove spark plugs from engines with aluminum heads, allow the ------ engine to cool. The heat of the engine, in combination with a spark plug that has run for many hours, may cause the spark plug to seize.

Whenever spark plugs are to be reused, the crushable design gasket, P/N 5612328, must be replaced each time the spark plug is removed. The correct spark plug installation torque is 18-22 ft. lbs. (25-30 NM).

NOTICE: Over tightening of a spark plug can cause stretching of the spark ------ plug shell and could allow blow by to pass through the gasket seal between the shell and insulator. Over tightening also results in extremely difficult removal.

Use applicable labor time and labor operation numbers for this operation.

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.