overheating issue..pls diagnose.

[rigd]

I'm posting this up for a friend of mine. He's pretty much looking for a second opinion on his overheating problem.

91 TSI

Issue: Coolant boiling over at idle with both fans on running constantly. He's tried with and without a thermostat (180*) and it still boiled over at idle. At freeway speeds, it would run hot also.

Things replaced: water pump, radiator, themostat, cap and hoses.

Any ideas what the problem is?? We have an idea, but we want to know your diagnosis on this.

Thanks in advance!

 

[AntiZeroTrip]

hmm, well the only thing you didnt replace is the sensor on the bottom of the radiator that would have the fans kick on to cool the engine. and if the cooling fan never kicked on I would say thats the problem, but you said that it has both fans running, so I dont know, just my guess.

 

[urcnjoe]

Test you cooling system to make sure it is flowing. Do a compression test and tell us the results. You may have a bad head gasket. Are you losing coolant? Check your oil to see if there is coolant in it and check your coolant for oil. Only things that I can think of off the top of my head.

 

[rigd]

hmm, well the only thing you didnt replace is the sensor on the bottom of the radiator that would have the fans kick on to cool the engine. and if the cooling fan never kicked on I would say thats the problem, but you said that it has both fans running, so I dont know, just my guess.

He changed that sensor also and it works. The fan is rigged so that he can have it on when ever he please.

 

[rigd]

Test you cooling system to make sure it is flowing. Do a compression test and tell us the results. You may have a bad head gasket. Are you losing coolant? Check your oil to see if there is coolant in it and check your coolant for oil. Only things that I can think of off the top of my head.

We suspected that it may be a blown head gasket too. I believe he pressure tested his cooling system a couple days ago. He says, it's fine. The only coolant loss is when it spits it out the overflow bottle. No coolant in oil and no oil in coolant.

We'll do a compression test on the car and I'll post up the results.

 

[boostcreep]

I have the same problem. Things I've changed since it started:

1. changed coolant mixture from 50/50 tp 75/25.
2. Added water wetter to help drop temps.
3. changed fuel trims to run slightly richer to help lower egt's

 

[PieTSI]

We suspected that it may be a blown head gasket too. I believe he pressure tested his cooling system a couple days ago. He says, it's fine. The only coolant loss is when it spits it out the overflow bottle. No coolant in oil and no oil in coolant.

We'll do a compression test on the car and I'll post up the results.

Are you sure he pressure tested the cooling system? There really isn't much more it could be besides the head gasket.

 

[rigd]

Are you sure he pressure tested the cooling system? There really isn't much more it could be besides the head gasket.

Yes, he did. I'll ask him what his results were on his cooling system check.

He is pretty much convinced that it's the head gasket. I hope that's the fix.