Hello, I have a question on an issue that is driving me crazy. On my 300SD the flow through of air is excellent, i.e. fan runs, air moves to slot at rear window, and is felt leaving the car in vents on each side of trunk. The windows never fog up and air is never stale inside. On my 1985 300TD it always seems stuffy and now, in winter, the rear windows are always fogged. I have searched the forum with every combination of words on this topic I can think of and find no mention of any passive air flow system.
The rear pillars on the wagon have a vertical series of holes on the outer sheet metal which is covered by the trim spoiler. Same on 240d. Are these holes vents? There seems to be some type of fibrous material in these holes. Filters? Besides the fibrous stuff there is water dirt and now ice.
Does anyone know if there is designed into the 123 chassis a passive air flow system, and if so, some way to maintain it?

Thanks so much
Doug