1994 GRAND PRIX OVERHEATING

  • Tiny
  • Jay Davis
  • 1994 Pontiac Grand Prix
  • 187,000 miles

My 1994 Grand Prix recently overheated. I removed the thermostat and tested it in boiling water. It was bad, so I replaced it. Now the temp guage reads between 150-225 while driving and moves toward the red when stopped. When you accellerate, it comes back down. The water pump looked fine. Is the sensor the likely culprit, or is there something else I need to check?

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Wednesday, December 28th, 2011 AT 6:03 PM

9 Replies

  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Temp sensor may have been damaged located on rear of engine. Was coolant system air bleed?

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Wednesday, December 28th, 2011 AT 6:12 PM
  • Tiny
  • Jay Davis
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I bled the air according to the procedure in the Haynes manual. When I first started it, there was still air trapped in the heater core though, I could hear it gurgle.

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Wednesday, December 28th, 2011 AT 6:56 PM
  • Tiny
  • Docfixit
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  • 18,991 posts

So opened bleeder valve till only coolant came out?

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Wednesday, December 28th, 2011 AT 6:59 PM
  • Tiny
  • Jay Davis
  • Member

That is right.

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Wednesday, December 28th, 2011 AT 7:01 PM
  • Tiny
  • Docfixit
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Can Ohm check temp sender @1k cold droping to @80 at 220. What temp is cooling fan coming on?

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Wednesday, December 28th, 2011 AT 7:09 PM
  • Tiny
  • Jay Davis
  • Member

I am not sure. Will have to check that.

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Wednesday, December 28th, 2011 AT 7:19 PM
  • Tiny
  • Docfixit
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Maybe fan issue to check if it will operate turn AC on fan should come on to prove its operational

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Wednesday, December 28th, 2011 AT 7:23 PM
  • Tiny
  • Jay Davis
  • Member

To Ohm check the temp sensor, do I check resistance between the two terminals?

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Wednesday, December 28th, 2011 AT 7:27 PM
  • Tiny
  • Docfixit
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Yes connector off

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Wednesday, December 28th, 2011 AT 9:29 PM

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