2002 Police Impala Overheating

I'm hoping that someone here has experienced this problem and can help shed some light on a possible solution.

We have a 2002 Police Impala with the 3.8 V6. Within the past two weeks we noticed that the car will overheat while idling. The idling period can last a few minutes to a half hour. This car has about 122,000 miles. The car produces good heat and everything is working the way it should.

The complaint that my firefighters have been telling me is that after the vehicle has been idling after being driven, the temp gauge pegs out in the red and some coolant boils out and onto the ground.

This car has been back to the dealership (Chevrolet) three times for this mysterious overheat problem and they have not been able to find the problem. Every time that the car has been at the dealership, they can not produce the same problem and the tests that they are running show no issues.

This latest overheat occurred last Friday when the outside temperature was 4 degrees.

I've had the thermostat replaced thinking that was causing the problem but now I"m left wondering what the problem could be.

Has anyone experienced a similar problem and had a solution presented to them about this?

My first thought would be the fans are not coming on but I am sure the dealer would have found that.

My first thought would be the fans are not coming on but I am sure the dealer would have found that.

thats what I was thinking but at 4 deg f its into the red and overheating that is not something I ever seen...with no fans....

It is possible that the water pump is n/g...if the internal fins are corroded the pump can't circulate the coolant enough at idle...but at 1500-2000rpm its ok....

this is simular to a water pump failure in a mercrusier out drive...at idle engine over heats when going at wot temp drops...

I have read about this before but never seen it for myself in these engines...

I would look to see if the fans are coming on when it's overheating, if they don't then you know where to start. If they are coming on then maybe it could be the water pump fins, but most intermittent probelms like this usually turn out to be a bad connection, an open in a wire or something like that.

I had a police package Chev Caprice that did the same thing and it was the fans not coming on. I just dont remember if it was a broken wire or sensor but whatever it was only costs $55

The complaint that my firefighters have been telling me is that after the vehicle has been idling after being driven, the temp gauge pegs out in the red and some coolant boils out and onto the ground.



This latest overheat occurred last Friday when the outside temperature was 4 degrees.
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Has anyone experienced a similar problem and had a solution presented to them about this?

the other possible componet that could cause this would be a head gasket leaking exhaust gases into the coolant and then the water pump can't pump air....this will require a coolant system pressure testing...

It would be also possible that the coolant cap is not holding pressure in the coolant system this would cause the coolant to boil then water pump can't pump air bubbles..

when you correct this let the forums know what was found..