Greggz72

The problem I am having is my temp guage quits working after about ten minutes. It will work fine for about that long and then it just goes dead. If I shut the car off and start it again it will work again for about ten minutes. Anyone know what could be causing this? Any ideas where to look first. I have already replaced the thermostat. Thanks in advance.

Mike Rohr

72 Corvettes have a single wire going to the sending unit in the block, (no ground wire), try removeing the sending unit and clean the threads on the brass unit and reinstall, DO NOT USE ANY TEFLON TAPE OR THREAD SEALANT. Or it will not make a electrical connection, I had the same problem on my old 72 .

Turbo-Jet

The temp gauge is based purely on a resistance change within the sender. You can measure this with an ohm meter. Take a measurement at start up, then again every 2 minutes. If the readings follow a fairly linear pattern as the head warms up, you know the problem is likely at the gauge itself. At the moment the gauge dies, check for continuity, indicating a short or ground in the system.

Ki m Le

The DG wire on the temp sender provides the ground path to the temp gauge! The temp sender acts as a resistor (as mentioned above) which controls how much the temp needle to deflect base on the coolant temp.

It's more like the temp sender is at false (resistant measures at infinity while hot engine is a bad sender).

Let's know what you find.

Greggz72

Thanks for the advice. I replaced the sending unit and it works great now. Gregg