I am a mechanic and have a problem with my audi a6 2.5 tdi bau engine code that has me exasperated!!!
Car overheated when wife was on her way to work - tested head gasket and it failed - Head gasket went on car aaagh!! - I drove car in to workshop with the engine running ok and no oil in water. Changed both head gaskets, water pump and timing belts - car starts and runs absolutely fine, brilliant.
However I now have neat oil from the engine going directly into the coolant system (no cream), within a matter of minutes the coolant has changed to neat oil in appearance.
I have joined the two coolant pipes from the oil cooler together to bypass this and rule this out, but it continues to refill with oil.
Does anyone know if there is a possible oil feed pipe that could have been reconnected incorrectly or is it a case of an oil/waterway having a crack in it allowing the oil in.
Heads were not pressure tested but were checked to see if they were warped and the oil was not previously showing in coolant.
As a follow up, if it is that I need to change the engine over, is it the same basic engine for all the 2.5 tdi's from 1999 to 2004 and I just need to transfer over ancilliaries?
Mant thanks in advance for any help you can offer