Overheating on 2005 Pontiac GTO

Car temp gauge reads over heating when electric fans kick on no signs of water leak or actual over heating symptoms seems to come and go and the radiator never boils over or shows signs of over heating... What could the problem be? concerned goat owner

Asked by for the 2005 Pontiac GTO
I wonder if the thermostat is sticking or the temperature gauge is just inaccurate. A repair shop will use a non contact inferred temperature gun to detect the actual temperature around the radiator, thermostat housing to see the real operating temperature of the engine. No coolant loss is a good signs, cooling fans coming on also good. Using a non contact infer-red temp gun to verify running temperature should be an easy in expensive test.

I read your answer on the 05 GTO over heating. I'm having the same prob. fans on, coolant level up, gm dealer says pump is working fine, tells me in excess of $700 to replace thermo because you have to replace the pump at the same time. You seem to indicate that the thermo can be replaced without replacing the pump. If so, how can I do this at home? PS I am not a mechanic nor technically inclined but I think even I can do this simple fix, I've done it before on an older car.
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Did you find out why your GTO was overheating? I also have a 05 GTO that says it's over heating after it idles for a while like at stops signs or heavy traffic. I rev the engine once and it goes down. Thanks for the help! My email is
did you get a response to your question about the second time your GTO overheated? If so, what was the suggestion? I'm having the same issue. FYI, local GM dealer tells me in excess of $700 to replace the thermostat because, as he tells me, the water pump must be replaced at the same time as it is a stand alone unit, one cannot be replaced without the other