I have an 05 plate A6 2.7 Tdi, which unfortunately over the last couple of months developed what I can only describe as a clatter which lasts for about 2 seconds on start up. I am almost sure that it is one of the chain tensioners losing pressure when the car isnt running, and therefore renders the timing chain slack momentarily on start up. I presume the oil pressure thsn kicks in and actuates the tensioner hence removing the slack.
Can anyone advise me if this is a common problem, and if any harm will be done if left untreated. Thanks in advance.
p.s. The car runs beautifully once started, and it only clatters when left for more than about 20 mins