Upon arriving home from 4 mile round trip light city traffic (25 mph aver speed), and entering base of my driveway, my well-serviced 2001 BMW 525I (60,000 miles) suddenly lost power steering, engine quit, battery warning lighting, and "service engine soon" light came on, and loud clanging noise came from engine compartment. Restarted car to pull from street into my driveway and smoke starting coming out of engine compartment. Shut car off and opened hood, saw steam coming out of cooling system expansion tank which had cracked. No more than 2 minutes occurred from time problem started until engine shut off. Upon investigation, all belts were shredded and belt pulley disc had come off and was sitting at bottom of engine compartment. Had car towed to BMW dealer next day. Although no injuries and car is covered by warranty, I am reporting as safety problem as dealer said that problem could have happened while driving on highway, which would have been catastrophic with engine suddenly quitting and loss of power steering. Dealer says that unusual that belt pulley would fail and simultaneous crack would occur in cooling expansion tank, although would seem logical to me that loss of water pump function would cause heat/pressure back up and cause tank to blow. Dealer says problem is due to wear on pulley rotator, which would cause wobbling over time. My safety concern is that there was absolutely no warning, car had been running smoothly with no indication of wobbling belt (total service 3,000 miles prior) and this was very sudden. Pulley should not come off -- somebody could be killed. New fan was installed in Dec 2001 per recall.

- Honolulu, HI, USA