2003 a6 4.2 cooling probs
 

I am new here. I just searched the 14 pages of threads and found one similar but had my own questions and circumstances. The coolant level was a little low last week. My girlfriend was driving Friday and the temp needle went way up and sent off the buzzers and warnings.

I am a mechanic but not real familiar with these cars. I have removed the expansion tank looking for cracks. Nothing. There is no fluid leaking anywhere (until it gets real hot). The upper and lower radiator hoses are the same temp, pretty damn hot!!, The main cooling fan seems to turn slow. The other two are for the a/c I believe.

What the car does is sit at the halfway point on the gauge and after about 10 minutes of holding the car at 2000rpm's the needle rises rapidly. The coolant will come out of the tank onto the ground, which it looks like it's designed to do.

Does anyone have any advice. I'm hoping it's not a thermostat. Do the clutch fans go bad on these cars?

Any help is greatly appreciated.

The fan clutches do fail. Does your electric fan turn on? I am not positive, but I believe the mechanical fan does most of the cooling but the electric fan is a backup, that and used for the a/c.

Your fan clutch should definitely be stiffening up (turning on) if your car is getting that hot. I would start there. They're also cheap.

Welcome to the forums and hope you get your sick car working soon.

Unfortunately I kind of suspect thermostat. The fan clutch does go bad once in awhile, but it should not shoot the temperature way up north, if the secondary fan is coming on. As for checking the fan clutch, turn the car off once the engine temp reaches above normal. If you try to spin the fan when the temperature is above normal, it should not spin freely.

Also the other way of checking is to run your hand over the radiator once the car is above normal. If the radiator around the return hose is cool, then it is pretty obvious that the water is not circulating.

Thanks guys. Come to think of it, I think I tried the main fan and it did spin freely at temp. I'll check again tomorrow. When the car is up to normal temp, both radiator hoses are pretty warm....to me saying that the coolant is circulating.(thermostat working). But I know better than to rule it out.

Will the secondary fan come on without the a/c on? The a/c is always on so I wouldn't know what's normal.haha. I've done all my tests with it off though.

I did notice that there was steam coming from between the cap and the expansion tank, so I replaced the cap today. It did make a differance in that it took longer to run hot and me shut it down.

Is there a necessity to "bleed" the system on my model? I am a transmission guy and not looking forward to removing the whole front end to do a thermostat.

This place is cool and I'm sure I'll be around for quite some time.

Again....thanks guys, any other ideas are graciously welcomed.

If it was the t-stat, your hoses would not be hot as no coolant would be circulating. In your case, I would start by flushing the radiator as that might be partially clogged. Also, check your oil to see if there is any coolant in it. You could have a blown headgasket.

Bob

I did check to see if there was coolant in the oil and there was not. I also held a piece of paper up to each exhaust tip while the engine was being reved up to see if fluid was coming out of the exhaust again with no problems noticed.

I'm going to check the fan clutch in a bit and see what happens from there.

Thanks again

Clutch fan was shot. I replaced it and was able to drive the car. It drove fine until I turned on the a/c. I decided that I had so much time involved that I could make more money doing my own work here at the shop. So off to the dealer it went. It needs a thermostat and all the related goodies usually involved with that labor intensive process. $1700. Wow, I love this car but......ouch! $$$$$

What's strange is the radiator hoses were both the same temp. Hot air came out of the vents with the heater on. Perhaps the t-stat was stuck partially open?

How many miles on the car? It may be time for a new water pump, timing belt and etc anyway. As for the price, $1700 sounds about right from a dealer. An independent shop will do it for a few hundreds cheaper.

There is 98000 on the car. The dealer is doing t-stat, water pump, tensioners and rollers, timing belt and serpentine belt.