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Temperature gauge fluctuates

W

wagatlng

New member
The temperature gauge in my 99 grand prix gt rises at idle, but never past 210 and then goes back down to while driving. I had a leaking radiator ane replaced it as well as both radiator hoses, thermostat, and cooling temperature sensor. After replacing these parts it stays at 210 while driving but goes up just before the red zone. Does anyone have any ideas as to what the problem could be? Please help. Thank you in advance.
 
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Sounds like air in the system. These cars seem to be sensitive to it.

Did you properly bleed the cooling system after replacing all those parts?
 
I bled it as best as I could, but I guess not good enough. I think I will buy a radiator funnel ans try to bleed it that way. Thanks for the help.
 


I don't understand your description.

I'm guessing it stays around 210F cruising down the road, but creeps up while idling and sitting still?

I would look into the fans if thats the case and forget bleeding. The fans should be running long before the red zone.
 
I have seen a couple issues in bleeding one or two cars. This can happen when an air bubble ends up in the million dollar location. Then it's a pain to bleed.

Best thing I've found is to pull the thermostat housing and thermostat back out. Fill to the top of the LIM if it isn't. Typically that's where I find the air bubble. Toss the stat back in and top it off.

That's what typically works. Best of luck..I once fought for 2 weeks. :confused:
Jack the front of the car up.. run it a little. change the T stat and refill through the hole was the best so far.
 


mr. tube your description is correct. the system seems to be working fine, i'm just having problems with the temp gauge
 
I finally found the problem. I had another leak, the heater hose fitting was leaking. I am set to change both of them on Wedenesday, hopefully this solves it for good!
 
wagatlng said:
I finally found the problem. I had another leak, the heater hose fitting was leaking. I am set to change both of them on Wedenesday, hopefully this solves it for good!
Click to expand...

This is where a pressure tester comes in handy, especially on an empty system filled with air :)

Air = far more likely to leak, and hiss.
 
I replace the elbows and that seems to have done the trick. I'll keep my fingers crossed that I have finally solved the problem. Thanks to all who have responded to my post.
 
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