I recently bought a high-mileage (159,000) '88 M3 and am enjoying the heck out of it. I have one concern that I would like an opinion on.
Sometimes when I start the car it makes a loud clattering noise similar to a diesel. After a couple of seconds, things quiet down. It happens about one time out of ten, sometimes hot, sometimes cold, sometimes parked at an angle, sometimes parked flat....
When I negotiated for the car, I was convinced that it was bad bearings from lack of a modified oil pan baffle and priced accordingly. But I've noticed that the oil light goes off quickly while the engine is still rattling away. I have adjusted the valves but this didn't seem to make any difference.