*see question if you don't want to read the background story *
Last month the serpentine belt on my outlander started making this ticking noise, it was replaced last Dec. It being under warranty I took it back to the shop that I had it replaced at (shop A). They charged me $20 to remove "gunk" off the belts and said it should be fine. 4 days later the ticking noise came back. Annoyed at shop A I took my outlander to another shop (shop B). They looked at the belt, sprayed water on it ticking noise disappeared, and recommended I take it back to shop A to get the belt replaced. So i take it to shop A, they look at the belt and after a work day of silence tell me that they replaced the serpentine belt. At the last second they call me to tell me that my idler and belt tensioner pulley are loose - which can cause the ticking noise and a bad belt. And here i am today with "new" belts and the ticking noise still exists.

My question is - if the ticking noise on my serpentine belt goes away after 40mins what could the cause be? If it were loose pulleys wouldn't the ticking noise last more than 40mins?