belt noise or something!

[sparkyork]

hi all since ive had me van which is about 2.5 months now, its always made an annoying noise when its got warm. for ages ive been trying to think what it sounds like so i can post somethin on ere! to me it sounds like a kinda mechanical cherp! anyone got any ideas?

also first things in the morning it ticks over all right but you can just tell a little bit that the revs are dropping off verey very slightly and coming back again, in a repetative motion, is this cos the deisel is cold or something else?