I've got an oil leak on AFB 2.5 tdi A6 (175K miles). Audi changed timing belt at Christmas and advised the leak was from the upper sump gasket and quoted to fix that. I've now had the gaskets replaced - but by my local garage ( not audi) and the leak is still there. My local garage now thinks camshaft seal on left hand side of engine ( left hand side if stood at rear of the car looking forwards) is the cause of the leak - with oil running down inside the timing belt cover and across the bottom and then leaking out down the sump. If this is right then I've wasted money having the sump gaskets changed on the advice of Audi and to fix the leak now means taking the timing belt off again with the associated costs that incurs. What's the view - my mechanic says (if he's right on the camshaft seal) he can't see how Audi could/should not have spotted the leak when they did the timing belt. If that's true then is it worth my while raising this with Audi to see if they will help with the cost of having to take the front of the car off again ? In addition has any one any advice on changing these seals - anything else to think of - my mechanic says to change rocket cover seals at same time.