Recently, this happened: http://www.audi-sport.net/vb/a3-s3-...s-when-you-need-least-might-forced-brake.html Originally I thought one of the engine mount bolts had worked loose resulting in the engine mount moving and hitting the tensioner, a broken block and later went on to discover it had some how lost timing meaning bent vales and a head re-build. . . Expensive stuff if you're not capable of tackling it your self! When I came to put the car back together a few weeks ago I'd found that the bolt had actually snapped! . . Here's the offending culprit next to a healthy bolt: I know it's recommended to replace the bolts every time they're removed but I'd imagine very few people actually do, including independent garages. But as you can see, it could save you a hell of a lot of bother! . . So basically, if you're doing it your self, use new bolts and if it's an independent garage doing it make sure they use new bolts!