You might have noticed your bimmer’s air conditioner making louder blowing or grinding noise just like that on a morning or suddenly after starting the car on full power and it persists. Rest assured you air conditioned motor or blower if you more acquainted with is not failing. This is the result of dirt making its way to the blower over time despite all the restrictive plastic protection covers from where the car takes in outside air and even through the cabin filter which is located on the passenger side below the glovebox just before air enters the blower area.
I had exactly the same issue and I checked the engine bay cabin air intake and the cabin filter, there were signs of small leaves that made there way in. I cleaned both but the grinding noise persisted at max fan power. I then decided to do a last inspection by removing the 3 torx 20 srews which holds the blower itself. To my amazement the small dried thin leaf made its way all the way to the blower motor and that very leaf was the cause of all this mishap and trouble I had to go through. You can clean the blower or remove dirt without having to completely remove it from the car and make sure you do not start the a/c or the car when removing the blower – the ideal thing to do would be to disconnect the negative battery cable but with some care it might not be necessary.
Below is an explicit video by our friend mattsbeamer from YouTube of how to get to the filter, he doesn’t explain how to remove the blower but it’s just next to the cabin filter compartment with 3 screws as described above. You can’t miss it ,the blower cables are quite thick to feed in the amps.