So i bought this audi knowing of it's overheating issue, thinking I could fix it.
I fell in love with the car after seeing it.

The problem with it, is that when I drive for about 10 minutes, the coolant tank boils and overflows from the reservoir. It never actually overheats, but the coolant temp gets to a crazy high.

I replaced the thermostat, timing belt, water pump, heater valve, and the coolant tank and cap. And the radiator is on it's way.

The thing is I didn't bleed the system when I did all these, but it was doing this before I even changed these things. Could this be the culprit? Or is the next thing the head gasket??

 

Anyone?

 

If it is the head gasket you will see indications of combustion products or oil in your coolant. If you coolant is clean then that is probably not your problem. Have you done a pressure test on your system? If the cooling system cannot hold pressure then the boiling point will be lower and you will get boiling coolant. Normally if it will not pressurize it is because of a bad cap or a cracked coolant reservoir. Since you have replaced both the the next culprits are the radiator and the heater core. In either case you would probably see or smell evidence of the leak. If the heater core is leaking you will smell coolant in the car when you turn on the heat. The leaking coolant would probably be caught in the condensate drip pan and drain out onto the road so you may not see evidence of the leak.

 

Thank you for the response

I did pressure test the system, and it holds it at 15 psi for however long I kept it on there.

And yes no pressure is coming from where you put in oil, no coolant in the oil, and vice versa.

And the radiator is the next thing I am going to replace, hopefully it works

 

when I did work on my car, and did not properly bleed the coolant system, the pressure release when the air bubble came through was enough to blow my upper radiator hose clean off! Not the same thing as the issue you appear to be having, but be sure you bleed the system properly after working on it.

good luck

 

I'm ( finally ) doing the head gasket on my 97 a6. Mine was doing a similar thing to yours, but it was putting steam out of the exhaust also. Look to see if you're getting steam too. You should hardly be able to see any exhaust at the tail pipe if all is well. White (coolant) or blue (oil) exhaust will point to the heads. When these cars overheat, the heads warp. No oil got into my coolant system, but the heads are definitely in need of machining.