Temperature guage on 79 chevy g20 goes haywire, back and forth between hot and cold
Have replaced the thermostat twice and guage keeps doing the same
craziness, back and forth. If I'm up to high speed on freeway, the guage levels
off on cool. Sometimes, as Im driving along a street, it'll level off to cool. Other
times, its a back and forth thing. If it idles, sometimes it's okay and not moving
and other times it's all over the place. What could be causing this?
Carefully inspect the wire(s) coming from the temperature gauge sending unit on the engine. Make sure there's no bare spots on the insulation. If the wire has a bare spot and intermittently touches metal it will cause the gauge to jump around. HTH. -Jim
Check head gaskets too.
Jim, do you know where the temp guage sending unit is on this engine?
Not off the top of my head. It's probably either at the thermostat housing or screwed into the side of one of the heads. It'll have at least 1 wire plugged onto it. HTH. -Jim
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