Head Gasket? Coolant incompatibilty?

Hi everybody!

I'm flummoxed.

1. I flushed and changed the coolant in my A4 V6 2.8 to normal blue coolant.

2. Car overheated and had brown foam in the header tank.

3. Thought it must be a head gasket, so I changed both head gaskets. Both looked fine and the heads weren't warped.

4. Flushed the system out many times and still brown foam in the tank.

5. Today I have about an inch of oil sat in the top of the expansion tank.

Any thoughts? I'm stuck now. :confused:

Cheers!

Gary

Oil cooler !

I've pressure tested the oil cooler on the water side and no leaks...

Just to be sure I have bypassed the oil cooler. I'm going to see how it goes, but I think I can see oil dripping out of the redundant water take-off. Fingers crossed you're right.