i recently have developed a whistling noise (very slight but consistent and
proportional to the engine RPM) ... coming from the engine of my 94 325is ...

i suspect one of the following:

1. main belt
2. alternator
3. a/c compressor

i remember a thread discussing this
topic some time ago but i don't find it
now ...

u guys think i should change belts first ?

any ideas/opinions welcome !

thanks,
radu.

http://www.bimmerforums.com/forum/showthread.php?s=&threadid=24321&highlight=whistling+noise i found the thread for you. sometimes u just have to use different spellings of the words used:D