I have the exact same problem in my 89. I had my mechanic look at it, and he found nothing. Of course I had to drive it to him, and it was gone by then. If you find out anything, please email me. Thanks The first time I start my M635 each day, there is a horrendous groaning noise coming from the power steering. Its worse as I turn the wheel side to side. It goes away once the car is warmed up, about 5 minutes down the road. The fluid is full, and there arent any major leaks, accept a tiny one near the resevoir. The problem does not re-occur throughout the day, even once the car has sat for an hour or more. Had a similar problem with an E30 once, but it was also leaking fluid like crazy right from the unit itself, shortly after, I needed a rebuild. Any thoughts? I would hate to be facing a major rebuild by letting this go on, but no ideas where to start.