Another Temperature Gauge Problem

[Oliver S.]

Hello,

I read the Ray Carneys problem with the temperature gauge from 6 th. July. First I thought mine ('65 Corvette) is the exactly same. After observing it closer while driving my Corvette it is different though.
When starting the car after a day the needle goes to the left. During driving it goes up:
1. when the engine is shut down after a couple of miles an restarted within a couple of minutes.
2. itself after a couple of miles (5-7) . When you then shut down the engine and restart it within - say 30 minutes - everything is fine, no dropping to the left.
Can it be a problem with the sending unit rather than the gauge? Seems to depend on the water temperature.

Regards
Oliver

[Gerard F.]

Sounds normal to me.

Oliver,

When you only drive it a few miles, the thermostat may not be open yet. When you shut it down and restart you maybe reading the heat from the engine, and not the coolant.

After you drive it a while, the thermostat opens and you are reading the coolant temperature. On my 67 small block after a long drive, shutdown, and restart after a few minutes, the gauge will always go slightly upward until the radiator brings the coolant down in temperature. If you do not restart for a while longer, the shutdown engine will cool slightly and you will be reading the temperature of the coolant when restarted.

At least that's what I have found.

Jerry Fuccillo
#42179