Temperature gauge pegged out

1991 GMC C2500
150,000 MILES • 3.7L • V8 • 2WD • AUTOMATIC
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KJEAN176
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  • 1 POST
Changed the water pump and thermostat last week. Temperature gauge was pegged out but vehicle was not over heating. Changed temperature switch and sensor and same thing. Hooked up after market temperature gauge and it is where it should be. I did not drain any coolant when I changed the sensor, could that be the problem? Do you have to drain the coolant to replace it?
Aug 17, 2018 at 7:27 AM
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HARRY P
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  • 2,292 POSTS
The problem is most likely in the gauge itself. It's stuck. Usually, they'll unstick themselves when you drive it and it warms up to normal operating temperature. Sometimes you might have to also tap on the dash with your knuckles a bit to get it going.

You can also drill a small hole right in front of it and push it back manually.
Aug 17, 2018 at 1:25 PM