Subject: Air Pump Noise - Air Injection Reactor System
Model and Year: 1966 Corvette
Source: Chevrolet Technical Service Bulletin
Bulletin No: TSB #66-62
Section: VIt
Date: May 20, 1966
TO: ALL CHEVROLET SERVICE PERSONNEL
An objectionable "chirping" noise in the air pump may be noted on early units equipped with an Air Injection Reactor System. This noise may be due to the vane ends rubbing the housing and the rear cover, vane shoe vibration, and/or vibration of the rotor seals under light back pressure conditions.
In production, beginning with date code 0126XX stamped on the pump housing, improvements have been incorporated as noted on page 2, to alleviate the above conditions.
Date Code
| 012 | 6 | XX |
| 12th Day of the Year | Last Digit of the Year 1966 | Shift and Plant Identifying Code |
If the "chirping" noise is most noticeable at idle speeds and is intermittent, it may be corrected by increasing the pump idle speed or by allowing additional wear-in time. if this fails, the pump must be disassembled and the vane ends lightly touched with emery cloth.
If upon completion of the above, the "chirp" still persists, or if the "chirp" is heard at higher pump speeds, the entire pump assembly must be replaced with a pump having a date code of 0126XX or later. Control of pump service components is such that there is no identifying feature to indicate the latest improvements.
Oil should not be injected into the pump to correct "chirp" since the bearing grease will become diluted and failure will result.
Article ID: 1026
Created: December 8, 2014
Last Updated: December 8, 2014
Author: Rob Loszewski
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article.php?id=1026