VALVE TRAIN NOISE - REPLACE LIFTER WITH NEW P/N LIFTER
Some 1987-1988 Allantes and 1988 DeVilles, Fleetwoods, Eldorados, and Sevilles (all vehicles equipped with roller valve lifters) produced prior to engine unit number T10L315315 may experience abnormal valve train noise with the engine at normal operating temperature. This condition may be caused by inconsistencies in the lifters' manufacturing processes. Engines built after the above breakpoint have received lifters, P/N 5235498 built with new process controls.
Revised lifters, P/N 5235498, can be physically identified by a dark blue pushrod seat and a gold colored snap ring. The earlier design lifter, P/N 5234660, should not be used.
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.