What the H#!! is this noise? Slant six mystery engine sound...

I noticed in the first video that the fan extension has been polished a bit by the PS belt. If the belt isn't under enough tension, it could hit the water pump pulley and cause both the polishing and the noise. The pump pulley moving back and forth could be what is causing the PS belt to not align properly on the crank pulley, throwing the belt onto the fan extension. If the car throws belts at higher rpm, the pulley alignment issue is the culprit. IMO