Flettner Roof Vent

Help… its always been a little noisy and I thought that the bearings must be on the way out. The last few days its been unbearable… silent from the outside, like an insane drummer that can’t keep time on the inside! I like the idea and have never had an issues with condensation…. I assume because of the vent.

Should they be silent when spinning from inside the van?
Can I service the bearings?
Is there a silent version or better option?


Have done a bit of research and taken a closer look at mine and it wobbles as it spins, in time with the clunk! They are supposed to be almost silent when spinning so I may take it apart and see if I can replace the bearing. I think it may have been hit with something in the past.