Asked by May 03, 2016 at 12:50 PM about the 2003 Pontiac Grand Prix GTP

Question type: Maintenance & Repair

My grand prix gtp heats up to almost redline in about 10
minutes. I shut it off when it hits around 240. I just
replaced the motor. As far as i can tell all the air is out of it
but it doesnt cool down. The fans will only turn on if i
unplug then plug the temp sensor back in. Any ideas?

3 Answers


the temp sensor sounds bad, but you shouldn't overheat that quickly. If you are sure the system is full and the air is out of the system, you may want to do a combustion leak test. the kit is 40-50 bucks at napa. it tests the radiator for combustion gasses. not hard to do, but if the test is positive, you likely have a bad head gasket.


Water pump circulating the coolant?


I'd still guess you've got air in the system. It's extremely hard to get out for some reason and simply using the bleeder doesn't always do it.

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