Check the link below kenny tells how he installed a replacement fan 10x10 fan from mouser bfb0512hha c with good results.
Xbox one psu fan noise fix.
My sons xbox kept making this weird noise while he was playing it was driving me mad someone said it was dust on the fan so while he was out i cleaned it i got the hoover and hoovered any where i could see that there was and vent leading inside the xbox and it worked for a short while so now every time i hoover up i go over the xbox and since i ve been doing that no whistling thank god.
My xbox one ac adapter started buzzing one day.
Put the psu away from sources of direct heat like radiator oven furnace amplifier or heat register.
Clearing out the dust made no difference.
Rune i had previously posted the wrong replacement fan apparently oem power supply fan hard to find a lot of links say fan not available plenty of complete power supplies though if you had too go that way.
Loud xbox fans are the bane of many gamers looking to get completely immersed in their game.
I took it apart and found the fan was the cause.