CLICKING NOISE DURING START P/N'S & INFORMATION

When diagnosing an apparent belt tensioner knocking or clicking noise heard mostly during start-up and shutdown on V6 diesel engines, check that the correct belt is being used. When a proper length belt is installed, the pointer on the belt tensioner should point to the shaded area shown in Figure 1 and 2. If the tensioner does not have a pointer, the stop lug on the tensioner pulley arm will be nearly midway between the stops on the ten- sioner body when the correct belt is installed (see chart below). Also make certain that the tensioner body is properly indexed on the mounting bracket.

SERPENTINE BELT USAGE

LENGTH ENGINE I.D. CODE (mm) P/N

(VIN V) Exc. A/C 6PK2523 2,523 22514557

(VIN V) & A/C 6PK2616 2,616 22514333

(VIN T) Exc. A/C 6PK1842 1,842 22514332

(VIN T) & A/C 6PK1867 1,867 22516490

If the tensioner is installed correctly and the correct belt is installed, inspect the crankshaft pulley for internal slippage. If the pulley has slipped internally, the attaching bolts will not be centered between the spokes (see Figure 3). If not, the pulley must be replaced.

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.