96 blazer belt or pully squeak

[bprosise]

I just bought a 96 Blazer 4door 4x4 with 72000 miles. I caught it at a dealer mis-advertised with a really low price. He agreed to sell it to me for that price but he wasnt gonna fix anything on it. Before I bought it I took it to a mechanic who told me it was in good shape but it had a gunked up radiator, and the serpentine belt was glazed. The belt was squeaking pretty bad at the time. So, it was still a good deal even with the repairs so I bought it. I had the belt replaced and the squeak went away. The mechanic sent me to a radiator shop to have the gunk cleaned out. Now after that is sqeaks again! Even more than before! The radiator shop said it got some coolant on it and it will drive off. Well I have put 200 miles on it and it still does it. I put some belt dressing on it and it helps at Idle but still squeaks under load. This wears off eventually. SO, could this new belt be ruined already? Could a pully be bad and how would I identify which pulley? Is there some sort of adjustment that needs to be done? The car runs great, I just hate my new wheels to sound like a hunk of junk!
Thanks for any help

[comp]

i've had to clean all the pulley's on different cars to quiet some down,
build up on them messin' with new belt