Hi folks, recently had a massive trawl through YouTube and found one of the worst horror stories I have ever come across, the company is called Vag Technic and they have done multiple videos on the V6 petrol engines fitted to the later RS4s and the Q7, it would appear that Q7s suffer with timing chain and cam gear failure due to the fact that the electronically controlled oil pressure on idle is so low it starves the gears of oil and causes premature wear and gear failure, the car concerned had 80k on the clock and was booked in to have the chains replaced as preventative maintenance quoted at £3000 and once inside the engine they discovered the cam gears were worn as well therefore they had to fit new cams only available from Audi at £4000 for both banks plus gaskets and seals, total £12,000 plus a remap for the oil pressure system which should make it last longer and the reason for the low oil pressure, yeah you got it, to cut down on the emissions as there is less friction caused by the oil pressure when idling, we then come to the RS4 of which they had two in both with the same problem, one had 60,000 on it and the other 26,000, the lower milage car had a scrap engine in the end and the higher milage they fixed, both had suffered cam follower failure except the lower milage engine had flipped a follower which jammed itself into the opposite side which held the valve open whilst beating the piston to death, hence the catastrophic failure, Audi apparently send vehicles like this to their company because no one wants to spend £25,000 up on a replacement engine which apparently will do the same thing again at some point soon, all third generation V6s fitted to VAG cars are suspect and depending on which model have built in failure points, therefore the lower milage car was apparently worth around £39,000 and as the guy doing the commentary said why would you buy something thats going to cost telephone numbers to repair sooner rather than later, if you are in the market for this type of engine I would seriously suggest this site as part of your in depth research.
Steve.