chirping noise from engine

I have a 2000 suburban, 5.3L. On cold days I get a chirping noise coming the engine when running or a pulley. I have replaced the a/c belt, and idler pulleys. I am thinking it may be the alternator, but have had no symptoms to indicate it. It doesn't do it if the temperature is above 45F. Has anyone had similiar issues? thanks

I have a 2000 suburban, 5.3L. On cold days I get a chirping noise coming the engine when running or a pulley. I have replaced the a/c belt, and idler pulleys. I am thinking it may be the alternator, but have had no symptoms to indicate it. It doesn't do it if the temperature is above 45F. Has anyone had similiar issues? thanks

I have had this occur since 2000..the upper idler pully bearing was causing this on the main drive belt..I put some lube at the bearing a couple of drops 20wt oil and it stops for a long time...

what is also common in cold damp weather is belt squeal...as the belt makes noise until the mositure is gone usually a few seconds.