For 1990-2009 cars

# ENGINE NOISE/KNOCK REMACHINE EXHAUST VALVE SEAT

COMMENTS MAY BE RECEIVED ABOUT A KNOCK OR NOISE CONDITION ON SOME 1982 3.8L AND 4.1L V-6 ENGINES WHICH IS SIMILAR TO A ROD KNOCK. IF IT IS ONLY PRESENT WITH A WARM ENGINE AND CAN BE SHORTED OUT ON NO. 2 AND/OR NO. 5 CYLINDERS ONLY, THE NOISE IS CAUSED BY AN INCORRECT MACHINING OF THE EXHAUST VALVE SEAT. REMACHINING THE NO. 2 AND/OR NO. 5 EXHAUST VALVE SEAT(S) WILL CORRECT THE CONDITION.

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.