This came up a year or so ago...
but I've never seen a solution.

At the rear of my right rear window on my 90 Westy Syncro there is a black
vent assembly that is attached to the window. Its purpose appears to be
equalization of inside and outside air pressures?

What bothers me is that it makes noise when the van hits bumps and rocks
from side to side ... even makes noise from side winds I think... (I notice
it does not make noise when all my windows are closed)... Is there any way
to service or alter this thing so it will shut up???

Does anyone know if this thing made noise when the vans were new?
(like is the only solution to buy a new one???)

Thanks,
Bill