Regal V6-231 3.8L VIN L SFI (1990)
Timing Cover: Customer Interest
Engine - Hum/Whine Noise
Bulletin 91-6-8
Date Oct. '91
Ref. No. 91-258-6
Corp. Ref. No. 106002
SUBJECT:
HUM/WHINE NOISE FROM FRONT OF ENGINE (INSTALL NEW ENGINE FRONT COVER)
1990-91 MODELS WITH 3800 TPI/3800 SUPERCHARGED V-6
MODELS AFFECTED:
1990-91 REGAL 1991 PARK AVENUE AND RIVIERA
A hum or whine noise between 1200 and 1600 RPM's on the above model Buicks can sometimes be corrected by installing a 1992 style engine front
cover. Some vehicles were built with front covers that may exhibit a harmonic resonance between the oil pump and cover.
DIAGNOSIS:
1.
Engine at normal operating temperature
2.
Sitting in vehicle with windows closed
3.
Raise engine RPM's to approximately 4000
4.
Gradually lower RPM's to approximately 1500 and listen for hum/whine noise
5.
If noise is present, install engine front cover, part number 12353384. Follow the service procedure outlined in the appropriate service manual.
Parts are currently available from GMSPO.
