My '85 244 and '86 245 (both b230f/m46) seem to be afflicted with the same problem. Best way to describe it is that they "whistle" at idle. If I increase the throttle, or under load, the "whistle" goes away (or is drowned out). I can't tell what part of the engine it's coming from on either car. Thought that maybe it was the WP, but can't imagine that I'd have two waterpumps going bad in two different cars at the same time. Sounds almost like a loose belt/pulley, or maybe an accesory bushing vibrating with the frequency of the engine?

Is this a normal noise for high mileage b230 engines to make? I've heard a few other 240/740 cars making this noise while idling in traffic/at lights, which means that it's normal and I'm worrying about nothing or that the cars all have the same thing wrong with them. :-)

Any ideas?

Thanks gentlemen...