1993 Other Dodge Models Belt(?) Noises

I have a Dodge B150 van with a mysterious squealing serpentine belt problem that happens only when the engine is cold, once warmed up the noise slowly goes completely away. The noise does not come back while engine is warm, even if it rains. I should note that all repair work has been performed by ASE certified mechanics who have all but given up on my noisy problem. The first mechanic replaced the belt AND the belt tensioner. We thought all was fixed, the noise went away for about three weeks and then came back. Then mechanic replaced with a "GoodYear GatorBack" belt. Worked fine for three weeks and squeal came back again. Next, a visual inspection showed belt was aligned with all pulleys properly and it was decided to replace the belt yet again with one size smaller. Three weeks later the squeal is back and my mechanic does not know what else to try. While squealing, the volts do not drop and the oil pressure remains steady. I hope someone can help, I've taken it to three different shops and besides being embarrassing and having spent hundreds of dollars, the noise is very loud and I wake up the neighbors in the early mornings while leaving for work.