Anyone know of a decent supplier for BMW parts, I need a coolant cap for a 1989 325i, it seems to be specific to the 325 model.

if you find it on www.realoem.com, you can get the oem part number, normally a quick google of that will get you suppliers with that in stock.

Alternativley a scrappy?

Last time i was down my local scrappy they had a few E36 Beemers

GSF or eurocarparts.

Eurocarparts usually have had most of the parts I've wanted and considerably less than dealer prices. Both OEM and pattern parts are available.