DIESEL VALVE TRAIN'TICKING' ENGINE BACKFIRE/PIVOT WEAR

Some 5.7L diesel engines may experience a valve train ticking noise and/or a backfiring condition. This condition may be caused by premature rocker arm pivot wear.

Original rocker arm pivots were sourced from two vendors. The vendor identification for both vendors can be found on the underside of the rocker arm pivot bridge (see illustration).

The pivot assemblies that are exhibiting premature wear are those illustrated in Figure B.

It is recommended that ONLY the pivots illustrated in Figure A be used when servicing an engine for the above mentioned 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.