V 3500 P/U 4WD V8-454 7.4L VIN W 4-bbl (1988)
Drive Belt Tensioner: Technical Service Bulletins
Engine - Serpentine Belt W/ Worn Idler Pulley/Tensioner
GMC NUMBER:
89-6A-107
GROUP:
6A - Engine Mechanical
DATE:
October, 1989
CORPORATE
NUMBER:
936204
SUBJECT:
SERPENTINE BELT WITH WORN IDLER PULEY OR TENSIONER (REPLACE PARTS)
MODELS:
1987-89 C/K, S/T, R/V, M AND G W/4.3L, 5.0L, OR 7.4L ENGINES (VIN CODES Z, H, K, N)
Some 1987-89 hght-duty trucks with 4.3L, 5.0L, 5.7L, and 7.4L engines equipped with serpentine belt drive may experience a condition where the belt
becomes loose and squeals or the belt may come off the engine drive pulleys. This condition may be caused by a worm idler and/or worm belt tensioner
pulley (plastic). If this condition exists, the following procedures may be used to repair this condition:
IDLER PULLEY ONLY:
1.
Using procedures in 6B-Engine Cooling, remove remove and discard the serpentine belt.
2.
On trucks with 4.3L, 5.0L, and 5.7L engines, replace the existing idler pulley with a new metal pulley, P/N 10129560.
On trucks with 7.4L engines, replace the existing idler pulley with P/N 10129561.
Parts are expected to be available on October 9, 1989. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency
VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges.
However, the part will be shipped premium transportation at dealer's expense. All other order types win be canceled as incorrectly ordered while
the 400 control is in place.
3.
Install new serpentine belt.
