I just got a 1996 Audi A6 2.8 wagon that I traded for my 1990 Honda civic worth probably like $1250 but when I got the Audi it was over heating thinking that it was in nice condition I got the car.I thought it would be an easy fix like the thermostat so I replaced the thermostat turns out it wasn't. What its doing is it will drive and stay at normal middle temp, and then while start bubbling and spray out of the cap and boil and steam and make a mess. I need help. Audi dealership is telling me $1800 for head gasket replace and I really hope you can help. Thanks! If you have any questions about it ask!

 

By the way, the half radiator fluid half water mix I have in the radiator is boiling and spraying out of The cap and its boiling so hot that it is melting my radiator tank. HELLLPPPP!!!!

 

Well I'm sure you have thought of this but you should not drive the car until you fix this issue :P

But now to some solutions:
Depending on how many miles the car has and when the last time someone replaced the timing belt you should consider in getting that done. Now while you are doing a timing belt job you will have access to the thermostat, the water pump and the radiator. Make sure you flush the coolant out of your system and make sure nothing is clogged (especially within the radiator).

Most likely doing the above will fix your overheating issue since those mentioned components (clogged lines or radiator and water pump) are the most common fail point for overheating issues.
Now you can also check if your fan(s) are running when the car is warming up, if they are not moving while the water is boiling it could add to the problem or even be the cause.

Unfortunately a timing belt job is not cheap if you go to a mechanic or even worse if you go to the dealership that above mentioned price does not sound to far fetched.

 

I just did that and replaced the thermostat and got the timing back to normal and got it done and I didn't think of flushing cause I don't exactly know how too. I want to be able to drive my new car that I got but no. It always has to be more.

 

You can have a local shop flush the coolant out, that way you don't have to do the the TB again.

If that doesn't help, you might have to look into the head gasket since that is the seal that makes sure you don't have coolant mix with oil or water and destroys your engine.

I have no more ideas if you have completed all these steps and still have the problem, sorry.

 

Have the coolant tested for combustion gases or pick up a test kit at a parts store. If combustion gases show up in the coolant, there is a a bad head gasket. If that is the case, do a compression test to verify.

 

I know this sound simple. But have your radiator cap tested.

 

^+1

If your system cannot hold pressure it will overheat.

Also, start the car when cold. If you see bubbles when it is cold you have a bad head gasket/warped head.

 

Where would the bubbles be coming out of? If it had warped heads and blowin head gasket it wouldn't there be white smoke coming out my tail pipe and it Would run crappy? I've been pouring radiator fluid into it and it is sucking fluid into radiator lines and stuff but it just keeps spraying the fluid out and the only time it says its over heating is after it sprays all the radiator fluid out. I have Audi mechanics telling me that they wanna charge me $375 to do a diagnostic on it but I don't need to be told all the problems just why its spraying radiator fluid.
Thanks!

 

On the compression stroke it would push air/fuel into the coolant, when the plug fires (if there is not too much water) it will push even more into the coolant and over pressurize the system. There is a lot more pressure in the system to force air into the coolant than there is vacuum to pull coolant into the cylinder.