Water Temp gauge acting odd in an '81

[Michael J.]

I have been having a funny problem with my '81's water temp gauge. When it is cold and just started, it pegs all the way right, way past the 250, but when I drive it a while and it warms up, it goes back to working properly and accurately. Any ideas what is going on? Thanks.

[Edward J.]

Re: Water Temp gauge acting odd in an '81

Mike, try to un-plug sender when cold and take a test light and ground it to block, then the touch the terminal with key on, generally the gauge will go up half way, (the bulb in test light acts a resistor) and see what happens, But sounds like the sender to me. This is a quick test of circuit and gauge.

[David H.]

Re: Water Temp gauge acting odd in an '81

Michael,

Any chance it could be the resistor on the back of the gauge going wonky?

http://repairs.willcoxcorvette.com/category/temperature-gauge-info/

[Michael J.]

Re: Water Temp gauge acting odd in an '81

Thanks guys. Ed, when I unplug the wire at the sending unit, nothing happens, the gauge stays pegged over to the right before and after starting. David, that could well be the issue, thanks!

[Edward J.]

Re: Water Temp gauge acting odd in an '81

Thanks guys. Ed, when I unplug the wire at the sending unit, nothing happens, the gauge stays pegged over to the right before and after starting. David, that could well be the issue, thanks!

Mike try a test light on the plug with the key on, you should see the gauge move to about to middle of the sweep. The temp. sender works like the rheostat on a light switch at home works on the same principal, turn the dial up and the light gets brighter . just to make it as simple as possible. sounds like there's a open in sender til the temp gets to a certain point.

[Michael J.]

Re: Water Temp gauge acting odd in an '81

Thanks Ed, I tried that and nothing happened to the gauge needle, still pegged over way past 260.