Why do some Audi cars have chain belts and some cam belts, i`m sure there`s a simple reason, i think i`m one of the lucky ones who have a chain belt after i was told from a local garage after a service that the cam belt had never been replaced and without taking the front of the car off they could not be sure if i was running on a cam or chain belt even when they made a call to a local parts firm who said i was on a cam belt, my garage advised me to call Audi where the car was sold from and they confirmed my A6 was using a chain belt, sigh of relive as i was not looking forward to a cam belt change and the costs involved 

Can sometimes be a mixed blessing as cam chains can also break the same as belts...think the 3.0 TDi is okay though