during a weekly warmup drive my temperature gage needle started dropping and ended up dropping to nearly sero during a period of about 5 minutes of driving at 35 to 50 mph. I restarted the car almost immediately after turning it off after arriving home, and the temperature started rising. Not to take chances, I shut the car down and waited for it to cool down. It showed no signs of running hot or overheating, and radiator fluid was full and certainly very hot. a few months ago I moved the sending unit from the overflow tank to the water pump as the new Hall tank had no provision for a sending unit. in the process I installed a new sending unit. I am assuming a contact problem, or the new sending unit or gage is acting up. Do any of you have a better idea? Old cars are fun.
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