Noise form rear


I have a 94 BMW 325iC and just recently began hearing a soft howling-type noise from the rear. It begins at approx. 25/30 MPH and does not get louder with speed. It’s not metal-on-metal more like air entering a crack or hole in a plastic container.

Any ideas


Deteriorated weather stripping or perhaps a loose air shroud at bottom of car.
Maybe even a loose inner wheel well cover.