Squeaking SerpBelt/ Pullys in Morning

On my 99 5.7 The Serp Belt was replaced once about a year ago, however I get squeaking in the morning especially when Damp while idling... A squirt of WD 40 just behind the topmost small pulley silences it a bit for a while, however it sounds like birds live under my hood. Any common probs or fixes? The belt is in good shape, with no oil or contaminents on it... Last vehicle I had I sprayed a Belt lube on it and it made it WORSE!

I have a similar problem now with my 01 K2500 8.1L. I don't think it has anything to do with the belt itself. It seems that the bearing or bushing on the tensioner pully is going south. I will probably take it to the dealer soon to fix, as I have a 100K B to B GMPP.

My 94 used to do that. I replaced 2 pulleys and a tentioner also, and it still squeeked in the mornings, or when there was moister in the air. I finally figured out the belt I was using, (even though new) was cheap and stretched out quickly. I went through like 3 of these belts in a year. I finally switched to a different brand of belt, and it didnt squeek for years. Try a different belt brand.