V 2500 P/U 4WD V8-350 5.7L (1987)
Fan Clutch: All Technical Service Bulletins
Cooling System - Excessive Fan Noise
GMC NUMBER:
88-T-49
GROUP:
6B - Engine Cooling
DATE:
November, 1987
CORPORATE
NUMBER:
866203R
SUBJECT:
EXCESSIVE FAN NOISE
MODELS:
1987 S/T MODELS EQUIPPED WITH 2.8L (VIN CODE R) ENGINES AND AIR CONDITIONING AND 1987-88 C/K, R/V, G AND
M MODELS WITH 4.3L, 5.0L, AND 5.7L (VIN CODES Z, H, K) ENGINES
Some 1987 S/T and 1987-88 C/K, R/V, M and G models may experience an excessive fan noise (roaring) condition. This condition will display itself as
the same type of noise on all affected light duty trucks, however, depending on specific model, may have a different cause.
^
ON S/T TRUCKS - this condition may be caused by the fan clutch remaining in maximum engagement Under normal operations, maximum fan
clutch engagement usually occurs following a cold engine start-up until the internal silicone fluid can be re-distributed and the clutch goes into a
normal engagement mode. The fan also goes into maximum engagement during maximum cooling demand conditions.
FIGURE 1 - S/T TRUCK
If a "roaring" noise is encountered, it can be repaired by installing a new design fan clutch, P/N 15602918 (See Figure No. 1). The new design fan
clutch will also be coded GN on the rear of the clutch housing. Use the service procedures in Section 6B-Engine Cooling of the S/T Service Manual.
