Cooling fans issue

[yetisn0wman]

Hi all. Google searches have brought me here and I have tried many suggestions with the issue that I am having

The car is an 06 Grand prix - I recently noticed the car getting hotter than usual. The fans will kick on if the AC is on, and also if I unplug from the coolant temp sensor and pop a paperclip in. They will not at any other time.

So far I have replaced the thermostat, coolant temp sensor and checked the relays. I do still hear a few air bubbles in the cooling system but I do not believe this would cause the fans to not kick on. I am running out of ideas from the web and I would one to be able to figure this out so I decided to join the community. I hope I just didn't buy a bad coolant temp sensor and this is all it really is.

Thanks for any advice ahead of time.

[BillBoost37]

When you say hotter than usual. How hot is that? In most 97-03's the fans were programmed on at 216F and 228F. I'm unsure of your year, but likely it's very similar.

[yetisn0wman]

When you say hotter than usual. How hot is that? In most 97-03's the fans were programmed on at 216F and 228F. I'm unsure of your year, but likely it's very similar.

It gets up to 3/4 of the way up and keeps going up if it sits idle. Fans used to kick in before it got to that point.

[BillBoost37]

It would be good to be able to see what actual temp it's hitting on a scan gauge. That way you can verify if it's the gauge, temp sensor or some other issue.

Nice thing is ..you know the pcm can command them on based on your AC test. You can do it based on shorting out the temp sensor. Or disconnecting..whichever it was.

But the question is.. does the pcm see the proper temp, or is the gauge off....or is there some other issue.

[yetisn0wman]

I wish I had all the tools a mechanic would have but unfortunately that is not the case. I was happy to see the fans kick on tricking the car, but was sad when replacing the CTS did no good.

[BillBoost37]

Maybe put up a post in your regional section to see if anyone can help you with a scanner etc.

[yetisn0wman]

Ok, it seems as my original issue was fixed by cold starting the car with the radiator cap off and letting it get very hot. Now the fans are kicking on when they should.

Now another problem I have is I hear bubbles brewing like there is air trapped in the reservoir. What is the best way to rid of this problem, and how bad is it for my car right now when it is doing this? Thanks all.

[boostedcompg]

bleed it out. little nut on top of the therm housing

[Scottydoggs]

the cap itself may be bad,

this is how i bleed my car.

i open the cap cold start, top it off, let car idle till the fans come on, that way you know the t stat opened, top off again if needed, open the bleeder, (up to 3 or 4 turns) keep it open till a stream of coolant comes out, then shut it, top off the rad again if needed, cap rad, done.

you can also squeeze the upper hose softly, as if you do it fast and hard coolant will blow out the open rad cap, air sometimes get caught up in the hose. do this after the fans come on.


and if all that fails, remove the t stat housing, and pour coolant right into the block till is full, then replace it, and re bleed it.

[yetisn0wman]

Thank you, I will let you know how it goes. Unfortunately the bleeder cap is currently broke so I am going to run to the parts store tomorrow for another.

[yetisn0wman]

So I thought everything was fine. I drove the car with no overheating issues all day, then tonight after a 10 mile drive the guage indicated I was almost to the point it could not go much higher. It was strange because the guage at one point would drop very steadily like it wasn't reading it correctly. I have never seen the guage drop that quick and it doesnt seem like the car is running that hot.

I did replace the thermostat but from my understanding there is also another one for the guage reading in the car. Where is this located and would it be worth replacing this first before I bring it in somewhere? The fans are kicking on just fine and coolant is flowing through. Thank you.

[boostedcompg]

The coolant temp sensor is right under the therm housing

[buck531]

I had an issue with my wife's 99 LS where the fans wouldn't kick on at the temp. it would go one notch above the middle line and then fans would eventually come on. I downloaded the bin file from the PCm to see if I could change the temp where it came on and it said it was "corrupt". I ended up finding another L36 Bin for a 99 Regal LS and it's been fine ever since.

Not saying this is your fix but it might be.

[yetisn0wman]

My original issue was the cooling temp sensor that went out. The problem was completely remedied by replacing the heater hose connector by the alt. There was a small crack that was causing me to lose coolant. Of course I had a mechanic figure that one out for me - also I was told my transmission fluid is very dirty, kind of almost like an "oil'. Should I get this fixed right away? And is it something I can safely do? Thanks all.