SERVICING CAM AND/OR CRANK GEARS (REPLACE GEAR SET)

MODELS AFFECTED: 1980-1990 SKYLARKS, SOMERSETS, AND CENTURYS WITH 2.5L ENGINES (VIN CODES R AND U)

THIS BULLETIN SUPERSEDES AND REPLACES BULLETIN 89-6-7B.

THIS BULLETIN HAS BEEN REVISED TO PROVIDE A SEPARATE TORSIONAL DAMPER FOR 1985-86 VIN CODE U ENGINES WHICH REQUIRE A DISTRIBUTOR TIMING MARK AND TO INCLUDE THE 1990 MODEL YEAR. ALSO, TO DELETE THE THIRD PARAGRAPH RE: THE 1985-86 SOMERSET AND SKYLARK AS THE REVISED PARTS ARE NOW AVAILABLE.

When servicing the camshaft and/or crankshaft gears on 2.5L engines, it is recommended that a new gear set kit be used to replace the individual gears. The gear kit is comprised of a set of camshaft and crankshaft gears for improved wear resistance.

It is also recommended that a crankshaft torsional damper be installed along with the gear set kit. The damper reduces critical crankshaft vibrations thereby decreasing camshaft and crankshaft gear wear. When the new damper is installed, the old crankshaft pulley may be discarded. If the engine currently has a damper, it should be reinstalled.

IMPORTANT: --------- The camshaft/crankshaft gear kit should be installed anytime the camshaft or crankshaft gears need to be replaced.

The kit part numbers are as follows:

Gear Kit Applicable Torsional Damper VIN Engine Code Part Number Model Years Part Number --------------- ----------- ----------- ----------- R 10101790 1980 - 1986 NOT APPLICABLE - Use existing crank pulley

R 10101790 1987 - 1990 10101369

U 10101789 1985 - 1986 10112485

U 10101789 1987 - 1990 10124651

GMSPO has superseded the individual camshaft gear part numbers with the gear kit part numbers.

Parts are currently available from GMSPO.

Use the appropriate Labor Time from the Labor Time Guide when replacing a Camshaft and Crankshaft Gear.

Refer to Buick Bulletin # 88-6-24 for details on camshaft gear removal and installation.

For vehicles repaired under warranty use:

Labor Operation: J0840

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.