First of all, let me welcome you to iRV2. You will find lots of great people here and lots of great info.
I had your same problem on my Ford chassis at the beginning. They replaced two fan belts and a belt tensioner. It would fix the problem for a short term and then it would come back. Finally figured out that for some reason, the OEM belt was just a tad to long and would make the noise after a short time. They replaced it with a AC Delco belt that was just a tad shorter and havent had the problem since.
Mike And Debbie- Northeast Ohio
2011 Ford F150 Ecoboost engine- SWEET!!
2011 Jayco Eagle 322FKS TT