Hello everyone. 2001 Honda Civic LX 5-Speed 169,935 miles temperature gauge has started glitching it'll rise up then go back down repeatedly. I let it cool down some opened the radiator and coolant is visible. And when I open the hood to feel the engine its not overheated. Also when I turn the car off then turn it to ACC the temperature gauge reads as High. What could be the caused of this and should I be concerned?
First thing I'd check on a 20-year-old car are the grounds, particularly the ground cable from the engine to chassis but other ground points as well. Hopefully it's that rather than a problem with a computer module. (I had a car with that problem and it was due to a bad ground but that was an older model where the temperature gauge was not operated by computer.)
Turns out it was my heater core plus a cable