V 30 P/U 4WD V6-262 4.3L (1987)
Fan Clutch: Customer Interest
Cooling System - Excessive Fan Noise
Number:
88-71-6B
Section:
6B
Date:
November, 1987
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 NO. 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.
FIGURE NO. 2 - C/K, R/V, M, G MODELS
^
ON C/K, R/V, M OR G MODELS - the condition may be caused by fan clutches that have mismachined housings. If this condition is encountered,
the fan clutch should be removed and the date code checked (See Figure No. 2). Use the service procedures in Section 6B-Engine Cooling of the
appropriate service manual. Fans built between Julian Date codes 07987 (079- March 20, 1987) and 11787 (117 - April 27, 1987) should be
replaced. New parts received from GMSPO should also have the date codes checked to insure a good part is installed.
