The serpentine belt starting squeaking on cold and damp mornings about 18 months ago at about 60K. I replaced it with a Dayco belt, and the noise went away for about 6 months. When the weather turned cold last winter, the noise came back. So I changed the tensioner with both pulleys right about when the weather warmed up, and it was fine all summer. Now that it has gotten cold again, the squeak is back yet again and as before it goes away when the car warms up. I did do the power steering pump o-ring replacement as well. I know it is the serpentine belt because when I spray it with water the noise immediately stops. Any other ideas?

 

Personally, I would buy a new OEM belt, and make sure the pulleys are clean before installing it. When my first belt started to squeak (at 84k miles) a little (on cold damp mornings), I massaged the tensioner (to loosen it up) and that stopped the squeak until 90k miles when I changed the original belt. I haven't had to change a pulley or tensioner yet. I hate noises too.