I have a 2004 (54) 2.2 136 bhp diesel. On start up in the morning there is quite a loud mechanical high pitched rattling sound from the alternator side of the engine. On depressing the accelerator it is continuous and sounds like a mechanical squeal (not slipping alternator belt sound). After a a couple of minutes it disappears. Only happens in the morning. Anybody got any suggestions? I was thinking mabe the water pump? Alternator belt is new.