Temp gauge bounces from hot to cold

2001 PONTIAC GRAND PRIX
107,120 MILES • 6 CYL • FWD • AUTOMATIC
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MDIETZ
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  • 3 POSTS
A month ago my car temp gauge was registering hot. It would bounce up to almost Red and back down to normal in the blink of an eye. I noticed it happened when I stopped and went to normal when the car was moving. I checked fans and they were working fine. I then had the radiator flushed and changed the thermostat and that seemed to work for about three weeks. Now I noticed a few days ago that the gauge would do the same thing, bounce up to almost red and then down to normal in a matter of 5 seconds. Now it happens even when the vehicle is moving. I don't hear any noises such as a water pump bearing , and I checked fluid levels. I commute 70 miles a day an worry its going to overheat. What should I do now. Someone suggested it could be a head issue, but I don't see how ,,what are some possible issues?
Jul 7, 2008 at 10:16 AM
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BMRFIXIT
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I have seen this problem before there is a loose connection at the engine coolant temperature sensor. Remove the connector and enhance the connection by creating a bend in the terminal.

Please run this test and get back to us.

Cheers
Jul 10, 2008 at 6:32 AM
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MDIETZ
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You nailed it, works perfect now thanks man.
Jul 15, 2008 at 6:02 AM
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