# Temp gauge acting like Loma Prieta richter scale



## Sonoma GTO (Jun 16, 2019)

Extreme high temp gauge fluctuation. All original gauges and want to keep it that way. 1965.. Going to replace thermostat tomorrow. Anyone have experience with temp sending unit and or gauge restorations?


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## Safe-T-Track (Jun 17, 2019)

Large variations in temp gauge are often due to pockets of air trapped in the cooling system. Lower coolant level so radiator is 1/2 full and let car warm up with heater running full blast. Watch water flow in radiator to determine if water pump and thermostat operate properly as engine fully warms up. As air is purged start refilling radiator with motor running at idle until 3" below filler neck then install radiator cap before shutting off engine or coolant can burp out of radiator upon shutdown. Let cool down, then check level in tank, top off to 3" below filler neck then check to see if temp gauge operates differently.


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## Sonoma GTO (Jun 16, 2019)

Thanks for the advise Saf-T... After it finally went flat dead, it dawned on me it was acting like an electrical short.. SAS the sending unit connector had vibrated lose... First loose, then finally completely off. Very embarrassing but... A quick cheap easy fix.. Works like new..


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