If you're mechanically inclined, take it off and see if the blower wheel is scraping on the housing or the screws that hold the motor. I've seen that a time or two. Loosening the set screw and recentering the blower wheel on the shaft ever so slightly is an easy fix.
I offer than based on my hearing of that video you made... it sounds like metal to metal scraping to me. My high frequency hearing isn't all that keen though so maybe I'm missing something.
Anyway, worth a look... those I fixed that way are still running and it has been over 10 years. I think it was due to natural wear on a thrust washer and too close of an install from the factory but warned the users that the bearing might be going out. One of those repairs was for a friend and ever time I see him now he gives me a shout out about how that bearing is still alive and doing well. LOL
I offer than based on my hearing of that video you made... it sounds like metal to metal scraping to me. My high frequency hearing isn't all that keen though so maybe I'm missing something.
Anyway, worth a look... those I fixed that way are still running and it has been over 10 years. I think it was due to natural wear on a thrust washer and too close of an install from the factory but warned the users that the bearing might be going out. One of those repairs was for a friend and ever time I see him now he gives me a shout out about how that bearing is still alive and doing well. LOL
