Hello!

I have an audi A4 1.6 (european model, I live in Europe) and I noticed that I get some weird gunk in my waterexpansion tank (the place where you put the coolent which goes to the radiator).
Now, I have 0 issues with the car. Ir drives great, it dosent over heat, it has power etc etc etc. I'm takin it to the mechanic tomorrow. But any help would be great!

EDIT: The gunk is a bownish color

 

If its not acting up you probably don't have a blown headgasket, someone or you might have put in the wrong coolant inwhen topping it off.

 

Was at the mechanic today. He said that the oil for Audi A4 that are made from 1998 on have water cooled oil. Oil is cooled in a special oil radiator, and when that radiator breaks down you can get oil in thewater expansion tank. Reason for this is because the oil in this radiator isunder3.5 bars and the water is under 0.5 bars. He took a look at this radiator and it was covered in rust, had water leaks and looked like crap. So hopefully this will fix my problem.

 

Well, it was the headgasket after all I also changed out the oil radaitor along with a ton of other stuff and now time will tell if everything will be ok. The car seams to be performing much better now...