Engine - Diagnosis of Rear Main Seal Noise
Number: 88-21Section: 6A
Date: MAY, 1987
Subject: DIAGNOSIS OF REAR MAIN SEAL NOISE
Model and Year: 1987 CAVALIER WITH 2.0L, L-4 (V.I.N. CODE 1) ENGINE
1987-88 BERETTA/CORSICA WITH 2.0L, L-4 (V.I.N. CODE 1) ENGINE
TO: ALL CHEVROLET DEALERS
Rear main seals are being replaced because of a "chirping" or "squealing" noise that goes away when an oil is sprayed into the area. However, improper engine ventilation can produce an internal vacuum depression which draws air past the seal.
If the noise symptom disappears when the dipstick cap is removed, preventing sump depression, then check the fresh air feed hole in the air inlet rubber duct for blockage where it connects to the rocker cover. Cut out any blockage to eliminate the noise problem and the need for rear seal replacement.
Labor Operation Number: T1224
Labor Time : .3 Hours