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Engine - Hum/Whine Noise From the Front
91oldsmobile05
NUMBER: 91-T-214
CORP.REF.NO: 106002
DATE: October 1991
SECTION: 6
SUBJECT: HUM/WHINE NOISE FROM FRONT OF ENGINE
INSTALL NEW
ENGINE FRONT (TIMING) COVER
MODELS/YEARS: 1991 NINETY EIGHT AND TORONADO WITH
3800 ENGINE (VIN CODE L)
A hum or whine noise between 1200 and 1600 RPM on the above model cars can sometimes be corrected by installing a 1992 style engine front (timing) 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 to approximately 4000.
4. Gradually lower RPM to approximately 1500 and listen for hum/whine noise.
5. If noise is present, install engine front cover (P/N 12353384). Follow the service procedure outlined in the appropriate service manual.
Parts are currently available from GMSPO.