I've had my valve cover gasket and cam tensioner seal replaced twice in the past 2 months. In each case, the valve cover area leak has come back. I trust my mechanic, as he claims that he's done over a hundred of these without a problem. The leak appears to be coming from the rear, passenger corner area of the valve cover.
Has anyone else experience such a thing? Any ideas? Both my mechanic and I are stumped.
Thanks in advance.

Tom
'98 Audi A4 1.8TQMS