I recently replaced all my belts; PS, AC and Alt. Everything was fine after the install - no noise. I've put about maybe 1300 miles on it since then install with about 800-100 on a recent trip. It was hot out so I used the AC a lot.
I was driving earlier and started to noise a fair amount of noise - I was on the freeway and had my music on and didn't know till I got off - drove about 29m before I noticed it. I had to drive that distance back to my house
I stopped at a gas station before my departure home and looked at the belts. The AC belt seemed to have a little bit of darkness on the bands of the belt - perhaps melting (though I didn't smell anything) or liquid of sorts (though I didn't see anything leaking)
The sound does not occur when I start the engine or rev it in park/neutral. Starts around 30mph and continues.
I'm hoping that maybe the belt is just a little loose, either the lock nut on the pully or tighten the adjusting bolt..
If there was a problem with the water pump, would it make this noise, or would other problems be occurring?