Hello All,
Just replaced the belts, idlers and tensioners on my 540i last night, and changed a PS hose too. On the way home from dinner tonight a whining noise developed, changes with RPM, and intermittently there will be a very loud screeching for a few seconds. The engine actually stalled during one of these screeching events!! Slight "burnt rubber" smell. Sometimes it will do it when I rev the engine up, sometimes not. Since its electronic throttle I cannot be under the hood and rev it at the same time, and no one to do that for me just yet....

There was a little hairpin looking bit with the alt/wp/ps tensioner that I had no idea what to do with it. Anyone know what it was for? I thought maybe it locked a tensioner but I couldn't find anywhere it would fit.....

If I had to guess I would say an accessory, alt, wp or ps is about to fail. Maybe the new tensioner instigated it, maybe not. I know that tensioning the alt/wp/ps belt is a b!tch, if somehow I screwed up the process, too much tension could have killed something?

I may tear into it tonight. Pull the belts and spin everything to see if I can feel the problem.

Any ideas welcome!