VALVETRAIN NOISE/ROCKER ARM DAMAGE (DOUBLE SPRING SEATS)

VALVETRAIN NOISE/ROCKER ARM DAMAGE

VEHICLES AFFECTED 1988 L-4 ENGINE (VIN CODE 1) IN ----------------- J AND L CAR APPLICATIONS

Customer comments of excessive valvetrain noise may be the result of the incorrect use of a double spring seat. To isolate, remove the rocker arm cover and examine the rocker arms for cracks or breakage in the spherical ball area.

Correspondingly, all the valve spring seats should be looked at carefully for a "DOUBLE" spring seat misbuild condition. Removing oil from around the base of the valve spring or relieving valve spring assembly load may be necessary to best observe the condition. This "two-spring seat" condition puts excess loads into the rocker arm, which can lead to a rocker arm fatigue failure. Any "DOUBLE" spring seat condition should be corrected by reuse of a "SINGLE" spring seat per valve assembly, and replacement of a damaged or a "Non- Apparent Damaged" rocker arm.

Use the service manual procedure and applicable labor operation. 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.