How to Install a V Belt on a BMW

1. Pop the hood. Locate the V-belt, which runs around the alternator and several pulleys. Follow it with your eye to a tensioner, which is identified by a hex-head bolt on one side and a bolt on the other side.
2. Loosen the locking bolt on the tensioner with an open-end wrench. Turn the tension bolt on the tensioner clockwise with the 3/8-inch ratchet and socket. Once you've taken the tension out of the belt, pull it off of the pulleys.
3. Run the replacement V-belt around the pulleys. Turn the tensioner clockwise with the 3/8-inch ratchet and socket again, then run the belt around the tensioner. Tighten down the lock bolt on the tensioner with an open-end wrench.