It started making the noise while I was using the BMW 5W-30 oil. When I changed the oil to Mobil 1 the noise went away for about 3000 miles then came back. I'm thinking of changing the oil again soon to the new Amsoil 5W-40 European formula (code EFMQT-EA) that meets the BMW LL-01 specification (it just came out in Oct).
I've been using Amsoil for years in other cars and it works well.
I do mostly highway driving with mine. I'm starting to think that it's fresh oil that helps, not necessarily the type. After the oil starts breaking down it's not quite lubricating as well, and the noise creeps up. Hopefully it's a problem that won't manifest itself for a long while!
Last edited by RoyFokker; 11-11-2012 at 10:21 AM.