I'm trying to figure out a cooling issue on a 2001 Chevy Lumina with the 3.1L V6. I've topped of the radiator and the overflow reservoir. If I start the motor and let it run for awhile, the top radiator hose gets significantly warmer than the bottom, which it is supposed to. I removed the t-stat this evening (which was located in the most ridiculous place possible, thanks GM!) and tested it in boiling water. It opens up just fine and closes just the same. The water pump does not appear to be leaking, which is usually a symptom of a bad water pump. I don't think the electric fan works, but is that enough to cause it to overheat? It will overheat driving down the road, not just sitting still and it will boil over, so I don't think it's the temp sensor. Any other ideas of what might be wrong? Could it be air in the system and it needs to be bled?

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I don't think the electric fan works, but is that enough to cause it to overheat?

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uhm yes.

there a bunch of grass, bugs, etc blocking the airflow? i would think you might get away with a busted fan while moving but maybe that car doesn't get good airflow to begin with.

Electric fan not working is a big deal. Or possibly the relay that turns on the fan?

[This message has been edited by madd_ag_05 (edited 4/10/2012 6:32a).]

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i would think you might get away with a busted fan while moving but maybe that car doesn't get good airflow to begin with.

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This usually happens while driving, which is why I think it is more than just the fan. If it was only overheating sitting still, then I would suspect the fan. I'll have to double check the fan when I get everything back together, because I'm not sure if it's working or not.

IF the coolant was never changed, the water pump impeller may be trashed.

See this:

This was a guys Towncar at work, 140K, never changed coolant.



No rattles, no coolant leaks.

Is this the last Lumina still running (kinda) in the United States?

My vote would be the impeller. No impeller, no water movement.

No water movement, no cooling, no matter what is going on.

~egon

sounds like a strong candidate to me as well

My first thought was the water pump too, but almost everything I've read says the pump will be leaking when it goes bad. I've had to replace the impeller on my boat a few times, so that's nothing new to me, I'll check it tonight.

I actually see a lot of lumina driving around, but yes it is a piece of crap and no it isn't mine.

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but almost everything I've read says the pump will be leaking when it goes bad

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If the shaft seals and bearings go out, you get a leak. If the impeller goes bad, the bearings and seals may still be good, therefore no leak.

I stopped at Lumina and just LOL'd a lot