Subject: Air Conditioning Compressor Noise
Model and Year: 1978 Corvette with RPO L48 Engine and M38 Automatic Transmission
Source: Chevrolet Dealer Service Technical Bulletin
Bulletin No: 78-T-76
Date: February 1979
TO: ALL CHEVROLET DEALERS
Some 1978 Corvettes with air conditioning may exhibit a rumbling type noise most noticeable at or just off idle RPM, with the air conditioning on, and the transmission in drive.
This condition usually occurs under high ambient temperatures and high head pressured and is caused by a reduction of compressor mounting bolt torque which results in compressor "wobble" and subsequent abnormal deflection of the compressor belt.
In production, the compressor mounting has been revised for 1979 Corvettes. Complaint vehicles can be corrected by using a new mounting bracket spacer, P/N 3976216, and the addition of a sleeve fabricated from a Corvette headlamp actuator sleeve, P/N 3922498, as outlined on page 2.
Article ID: 954
Created On: Mon, Oct 13, 2014 at 8:54 AM
Last Updated On: Mon, Oct 13, 2014 at 8:54 AM
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/1978-corvette-service-bulletin-air-conditioning-compressor-noise-954.html