Replacing the alternator belt on most cars is relatively easy, since they are usually somewhere pretty accessible. Thanks the tight packaging on the uniquely styled Audi TT, however, replacing the alternator belt on this car is a bit more challenging. By using the following procedure, it should be pretty straightforward, though, and can be done in a couple of hours. This applies to the first generation Audi TT, made from 1998 to 2006.
Tools Used: Tools, 15-mm box wrench, Set of sockets and ratcheting wrench, Screwdriver, Allen wrenches
Change the Alternator Belt
Disconnect the negative terminal of the battery. Remove the plastic trim on the passenger’s side of the engine bay. The alternator is located on the left side of the engine (as you are looking at it) between the bottom and top of the motor. Remove the trim that covers the manifold. Loosen the clamp that holds the air intake pipe and remove the rubber hose portion for access. There is also a black canister above the alternator that needs to be moved.