My wifes '96 E36 323 coupe has started to whine. The best way I can describe it sounds like a supercharger whine. The first time I heard it I thought it was sucking air but I have since changed my mind. It is mainly when the engine is cold but driving home from a friends place last nite it went on for most of the drive home. I have tried to pinpoint where it is coming from and i think it may be either the drive belt itself or an alternator bearing (the rear bearing possibly) or the tensioner pulley. has anyone experienced the kind of noise before? Any suggestions would be most appreciated.