S15/T15 2WD P/U V6-262 4.3L (1988)
Fan Clutch: Customer Interest
Cooling - Cold Start Fan Noise
BULLETIN NUMBER: 92-66-56A
SECTION: 6B Engine Cooling
NUMBER: 2
CORPORATE REFERENCE NUMBER: 1662O3R
DATE: May 1993
SUBJECT:
COLD START FAN NOISE (INSTALL REVISED "QUICK DUMP" FAN CLUTCH)
MODELS:
1987-92 M-VANS WITH 4.3L ENGINE
1990-92 L-VANS WITH 4.3L ENGINE
1988-92 S/T TRUCKS WITH 4.3L ENGINE
THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 92-6B-56. IT IS BEING REVISED TO INCLUDE M/L VANS, AND TO
SERVICE PARTS INFORMATION AND RPO DEFINITIONS. ALL COPIES OF 92-6B-56 SHOULD BE DISCARDED.
CONDITION
Some owners of 1987-92 M-vans, 1990-92 L-vans, and 1988-92 S/T vehicles with a 4.3L engine (RPO LB4, LU2, or L35) and air conditioning (RPO
C60) may experience higher than normal fan noise upon cold start up (usually fan noise extended beyond 90 seconds after start up).
CAUSE
This condition may be due to an extended engagement of the fan clutch.
CORRECTION
The condition may be corrected by installing a revised fan clutch which reduces the fan clutch engagement cycle. Vehicles built after the following VIN
breakpoints have the new fan clutch installed in production:
Plant
VIN
Moraine
N2514836
Shreveport
N8512403
Pontiac West
N0508347
Baltimore
NB534465
SERVICE PROCEDURE
Refer to section 6B1 "FAN CLUTCH REPLACEMENT" in the appropriate Service Manual for removal and installation of the fan clutch.