Hi, this its a solution that will remove the warranty but it works normally...
Try to remove the PSU from the pc, open it, remove the sticker on the middle of the fan and then remove little rubber and put some lubricant where you removed the rubber, close it again and it should work again without any sound.
I did it with my PSU and all worked fine again and still does after 1 year from this process. Hope I helped you good luck 😀