Since I have had my car (1.9Tdi PD130) there has been an odd noise whenever I put the air con on, well now it happens sometimes when I put it on econ too and also in the morning when the engines cold for the first few minutes. The sound only occurs when the engine is running between about 1000-1500rpm. It sounds like a rattle and can be quite loud. I have googled this a lot and from what I can tell it can possibly be the alternator clutch.
Any one else had this problem before?