SQUEAL OR POPPING NOISE CRANKSHAFT PULLEY AREA. GMC Truck GMC G Van 1986

MODELS: 1986 C,K,G,P 10/1500 - 30/3500 EQUIPPED WITH THE 4.3L (VIN CODE N), 5.OL (VIN CODE F,H), 5.7L (VIN CODE L,M,K)

Some 1986 C,K,G,P model trucks equipped with the 4.3L, 5.0L, 5.7L engines without air conditioning (A/C) may experience a belt squeal or popping noise from the crankshaft pulley area. These noises may be caused by a separation in the generator belt groove portion of the pulley.

If this condition is encountered, it can be repaired by replacing the pulley with a new design pulley. These pulleys were changed in production effective with the following VIN breakpoints.

Model Plant VIN Breakpoint ----- ----- -------------- C/K Flint - Line 1 GMC 729913 Chevrolet 426588 Line 2 GMC 528408 Chevrolet 192683 St. Louis GMC 530639 Chevrolet 119883 Janesville GMC 511469 Chevrolet 128233

G Van lordstown GMC 518113 Chevrolet 118449 Scarborough GMC 525644 Chevrolet 163060

P Detroit Assembly GMC 503976 Chassis Chevrolet 330510

PARTS INFORMATION

New Part Quantity Number Description Application Required ------ ----------- ------------ -------- 10069912 Pulley C/K,1,2,3, 4.3L 1 (N) w/o A/C

C/K,1,2,3, 5.0L 1 (F,H) 5.7L (L,M) w/o A/C

P2,3 5.7L (M,K) 1 w/o BM3, w/o A/C

10069913 Pulley G1,2 4.3L (N) 1 w/o A/C, V05

G3 (03-05-06) 4.3L 1 (N) w/o A/C, V05

G1,2 5.OL (F,H) 1 5.7L (L) w/o A/C, V05

G3 5.7L (L,M) 1 w/o A/C, V05

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.