My 2001 Audi A4 Quattro (99.5K miles) died while I was on a highway. Fortunately no accident. My mechanic showed me that the camshaft chain tensioner failed (had some slack), valves damaged, etc. He has to replace that part, new valves, and rebuild the cylinder head. Replacing timing belt/water pump while he's in there. Obviously a very expensive job. Why would the tensioner fail? Is it normal wear and tear? Several years ago Audi issued a warranty extension covering "oil sludge" related repairs. Could oil sludge be the cause? Any help will be greatly appreciated!

 

What i find is sludge engines are the fault of the owners not changing the oil enough & the incorrect oil being used. That is what probably happened to yours.

As far as the repair get a exchange cylinder head from Audi. They come complete with valves , lifters , cams & tensioner. It is silly to try & rebuild the cylinder head by piece meal , especially after it has been previously neglected.