Welcome to Allpar, Looks like a nice ride. When you get a chance post some pics.
Try what KOG is saying to help narrow down the noise, I think it has something to do with the serpentine belt. Could be a hydraulic pump or A/C unit or a bearing attached to any part of the belt. Most of the time humming noise is a wheel bearing but the noise is surging so that why I think it's in the belt somewhere. Try moving each pully/bearing on the serpentine belt and if you have any play(side movement) that would be a good indicator.
Try what KOG is saying to help narrow down the noise, I think it has something to do with the serpentine belt. Could be a hydraulic pump or A/C unit or a bearing attached to any part of the belt. Most of the time humming noise is a wheel bearing but the noise is surging so that why I think it's in the belt somewhere. Try moving each pully/bearing on the serpentine belt and if you have any play(side movement) that would be a good indicator.
