1965 - 1966 Corvette: Service Bulletin: Temperature Gauge Reading Too High
Source: Chevrolet Technical Service Bulletin
Subject: 1965 Corvette Temperature Gauge Reading Too High
Model and Year: 1965 Corvette
Bulletin Number: DR #774
Date: November 23, 1965
TO: ALL CHEVROLET DEALERS
On the 1965 Corvette, objections to high engine temperature may be encountered. Hard driving, heavy stop and go traffic or prolonged idle periods, especially in high ambient temperatures, will produce a gauge reading in the upper part of the band. This positions the gauge needle close to the "HOT" position even though the coolant temperature is within safe operating limits (indicated by no coolant loss).
The 1966 Corvette temperature gauge has been re-calibrated so at any given temperature, the needle will be positioned farther to the left. Under most operating conditions, gauge readings will be around the center mark or left of center. Under extreme operating conditions, gauge readings to right center are normal.
The 1966 gauge, Part No. 6402594, should be used to satisfy owner complaints off high temperature gauge readings on the 1965 Corvette.