BELT NOISE/WEAR ADJUSTMENT

MODELS: 1988-89 C30, K30, AND R20 EQUIPPED WITH 7.4L ENG (VIN N)

Some C, K and R Trucks equipped with a 7.4L engine and serpentine belt system may have a belt noise/wear condition. This condition could be caused by a misaligned serpentine belt system. In a properly aligned system, the belt should be close to the center of the tensioner pulley, and the pulley should extend past belt edge both front and rear. If tensioner runs rearward of belt center, add 1/16" washer (P/N 120394) behind inboard rear leg of generator bracket and cylinder head (See illustra- tion). Rotate engine to reverify alignment. In cases of severe misalignment where pulley contacts 2/3 of the belt width, a 1/8" thick front end suspension shim at the same location will work. Parts are currently available from GMSPO.

Labor Operation Number: T7850

Labor Time: .4 Hours

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.