A4's have a poorly designed cam tensioner that eventually leaks oil. the cost to repair the item is approximately $1000. the dealer (carousel audi) even admits to the fact that it is a poor design and there have been numerous complaints about it at the dealer. i've also read numerous complaints about it on audi forums. the leak typically found shortly after the warranty period has expired. i feel strongly that this should be a recall on all respective cars to have it repaired! *nm