# Cooling Issue Again.



## Weisberg16 (Jan 5, 2011)

Okay so my GTO has had more cooling issues then ever and so about a month ago I replaced the radiator and thermostat plus all the hoses and coolant. Well just the other day I noticed my cars temp get up to 217 and it usually runs at 192. Well the temps only climb during idle and when I start driving they start to go back down. I am stumped at this point and might have to let this project go because truthfully I am about ready to pull my teeth out over this car. If someone would be willing to give me some ideas that would be great. Oh all the fluids are fine and pressure tested the system and it is fine. Don't know.


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## poof1887 (Sep 21, 2010)

Is ur car an A4? What position on the temp gauge is the needle at when it's "running normally" vs. when it's running hot?


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## 06BLACKGTO64 (Oct 30, 2010)

did you check fan operation? if its only doing it at an idle that seems to be a good chance


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## poof1887 (Sep 21, 2010)

The 05 A4 I had used to change temps a lot, it was just a byproduct of driving and getting fresh flowing air in the engine compartment then stopping the flow when I slowed down and she would then heat up


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## Weisberg16 (Jan 5, 2011)

Yea I checked the fans and they are running perfectly. It is a manual and it has always ran between 192-197. Never above.


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## 06BLACKGTO64 (Oct 30, 2010)

how well did you "burb" the system when you did the radiator? this might be far fetched and idk how much driving you have done but there maybe an air bubble causing it..id run the engine with the radiator cap off and see if the coolant ever drops


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## poof1887 (Sep 21, 2010)

Weisberg16 said:


> Yea I checked the fans and they are running perfectly. It is a manual and it has always ran between 192-197. Never above.


Yea, temperature fluctuation doesn't happen on the manuals.... I'm stumped, sorry


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## GTO JUDGE (May 14, 2005)

Sounds like you may have air in the system. What degree thermostat are you using? Where did you get the thermostat? Is it a quality one or a cheap one? I had gotten a thermostat already for my '70 from AutoZone and it didn't function properly. Went to NAPA and got a stant and its been working fine.

When you worked on the car did you have say a paper towel or cloth in the hoses etc to protect from dirt etc and forgot to remove before assembling? I have heard of this happening.


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## Poncho Dan (Jun 30, 2009)

If you weren't aware, the stock tune doesn't engage the radiator fan(s) until like 223 or something like that. So until you get it tuned for tighter fan settings, it's going to have wild temperature swings. Even worse if you run a colder thermostat.


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## 06BLACKGTO64 (Oct 30, 2010)

just to back up GTO JUDGE if your thermostat is bad check to see if the upper radiator hose is pressurizing after the engine has been running for a bit, you will notice that once the coolant temp reaches the thermostat temp the upper hose will pressurize to where you would not be able to collapse it be gently squeezing it.


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## Weisberg16 (Jan 5, 2011)

Yea thanks for all the input. Today I tried burping the system again and it still climbed very slowly up. Got to about 210. I have a tune and I can set my fan temps to whatever. So today so I took out the stock T-stat and put in an SLP 160 degree stat. I am waiting for the car to cool down for a minute. This car is being a nightmare. The hoses are pressurizing and the temps are still climbing. GTO Judge I was also running a stock stant T-stat. What other options are there?


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## GTO JUDGE (May 14, 2005)

Weisberg16 said:


> Yea thanks for all the input. Today I tried burping the system again and it still climbed very slowly up. Got to about 210. I have a tune and I can set my fan temps to whatever. So today so I took out the stock T-stat and put in an SLP 160 degree stat. I am waiting for the car to cool down for a minute. This car is being a nightmare. The hoses are pressurizing and the temps are still climbing. GTO Judge I was also running a stock stant T-stat. What other options are there?


I only use Stant. The one from autozone was a Stant that was bad. I prefer dealing with NAPA, I rarely ever use AutoZone or Advanced auto for parts unless its a non essential minor item.


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## Weisberg16 (Jan 5, 2011)

Yea I always go to autozone but if it is the t-stat then we will find out out soon as I check the coolant levels after the cool down.


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## Poncho Dan (Jun 30, 2009)

Again, you're not going to see a change until you tune your fans down to a lower temp. Otherwise your temps are free to float anywhere in the range between when your thermostat opens and when your fans kick on.

Tune your fans down to 199 or less, you'll never see your temps go over 200 again.


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## Weisberg16 (Jan 5, 2011)

My fan is tuned to 195 for high and 185 for low and it is still jumping above 200. At this point I think there is something else wrong. Hmmm. For the 160 when should I tune the fans to turn on???


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## Poncho Dan (Jun 30, 2009)

Weisberg16 said:


> My fan is tuned to 195 for high and 185 for low and it is still jumping above 200. At this point I think there is something else wrong. Hmmm. For the 160 when should I tune the fans to turn on???


The stock operating system in the PCM only controls down to 192. You need a custom OS below that. If you're truly tuned to those numbers, I'd see if I could force fan function through the tuner (manual "ON") to see if the cooling fan circuit works, then go from there.


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## Weisberg16 (Jan 5, 2011)

I do have a custom OS done by F.A.S.T. but it is locked right now so I think I am going to have to wait to get the tuner to unlock it. : /. I tried going through it but it wouldn't do anything.


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## Poncho Dan (Jun 30, 2009)

I'd give them a hard time about locking their tune - that's what I'd consider a pompous douchebag move. ...Like their tune is the be-all, end-all of tunes for that car, with "special" proprietary information...  Some tuners really inflate their ego once they figure out how to do it. Ask me how I know.


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## Weisberg16 (Jan 5, 2011)

How do you know??? LOL. Looks like I will have to pay someone to change my fan turn on points...


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## Poncho Dan (Jun 30, 2009)

Well, there's been a few instances where I've gotten into fights with "pro" tuners as to their methodology and inflated dyno numbers for a given mod. They sicken me with their elitist attitude.

I'd say tunes are probably locked 99% of the time because they don't want anyone finding out that they paid $400 for someone to do a worse job than a drunk kindergartner. Just because they have a dyno, people automatically trust them...


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## Weisberg16 (Jan 5, 2011)

Yea well now I have drop more money on a fresh new tune... Maybe I can make it worth while by upgrading something that will give me more power. I'll tell my new tuner to not lock it so the dealership can still do their diagnostics on the car.


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## Weisberg16 (Jan 5, 2011)

Alright well the car is overheating when the AC is turned on... Any ideas. I am about to scrap this project and move on if I don't fix it.


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## jpalamar (Jul 22, 2008)

Double check relays/fuses?

Check the fan setting on the tune?

Maybe the coolent temp sensor is out of wack?

Take the t-stat out and drive, see if it overheats then?

Water pump bad?

Flush the cooling system, partial clog?

Air pocket?


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## Weisberg16 (Jan 5, 2011)

K. I checked a couple of the fan relays and they look a bit toasted but the fans run fine...I also have burped the system so many times and nothing. Maybe it could be the water pump going but I want to fix all the least expensive stuff first. Then work on that. It is weird because it is fine until the A/C COMES ON but the fans turn on when the ac is on.


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