Hi all 2003 A4 fsi 150.000 miles on clock, oil breather pipe crappy plastic design, one that has a bit attached to it split. Also dipstick funnel was replaced by a rubber hose who ever had car before me replaced the funnel or had it done no idea why didnt spend Â£3. so i booked car into garage to get sortd i no the manifold had to come off, i also asked to check timing chain tensioner as i had no proof was done at cam belt change. and also to price cylinder head gasket as there is a very slight oil leak not major I phoned garage to see how he got on he said that he didnt have specialist tools to get to timing chain. And to remove cylinder head. Ino rule of thumb is if it rattles change if not leave well alone..i have read stories of chains going. So he phoned an engine specialist and was told if the car is running ok. Advise customer to leave alone when changing breather pipes and chain tensioner and cylinder head gasket this would affect the bottom end of the engine ie blowing it out.He has had experiance of this on 3 engines 1 audi when he did head gasket and decoked valves it destroyed the bottom end..and he will only work on engines upto 90.000. Am i right to be slightly confused with this. As several guys on her and other forums changed theres with no problem at all especilly blowing out the bottom end..