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I would suggest pulling out the sensor (have a plug or rag ready to plug the hole) and cleaning it off. Put it back in and see if it works. See what happens and then move forward from there.
Originally Posted by mike914
Hello
Well This was a self inflicted problem
I have a 1968 with a 327 HO motor
Was running at about 210 steady no overheating just felt it was a bit high.
I poured in a bottle of Hyper cool super coolant
now the temp guage will not move from zero
after running car for 20 miles the top coolant hose still feels cool to the touch
should I drain some out and replace with distilled water or 50/50 coolant
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I agree on the sensor. Adding fluid shouldnt have any effect and 210 on the highway at 3000 to 3500 rpm is about normal. Im guessing thats your rpm since my 3.55 and 3.70 gears both ran at that temp
First I'd go watch the Youtube video, then take a look at the picture below.
Testing a 68-76 Temperature Gauge -or- What your non working gauge can tell you!
The gauge will tell you what the problem is... .
So go to the sender make sure the wire is connected, if not connect it. If it is connected pull the ohms wire off and with the key on look at the temp gauge. It should read like the lower left corner. Then ground out the sender wire with the key on and it should read like the upper left corner in the picture below. If the gauge functions like this the issue is the sender.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
If it doesnt work and you pull the temp gauge to test it, you may as well replace the 90 ohm paper resistor on the back with one of Willcox's adjustable resistors. They work awesome and you can fine tune the gauge to be correct. I tested mine with the thermostat and the electric fan Thermostat on my 68 and it was dead on on both once adjusted. My fan comes on at 195*F and my t-stat opens at 160*F. Then I used a infrared thermomter on the t stat housing to verify and they matched.
temp gauge stopped working
