Postby Cooper » March 18th, 2010, 9:09 am
It's the way the "vent valve" for external/internal air is designed. It's like a trap door and does not seal in the manner you'd expect. The edges of the "trap door" is lined with sponge/foam. All A/C vent systems are generally like this, it has to let some air bypass to equalize the internal and external air pressure....I know it's not an aircraft but it helps out people with sensitive ears when going up and down hills.
The foam is there to filter out dust when the external valve is closed, but it is not a real filter. In fact, the system has NO FILTER. There are also other vents in the cabin that let air in or out, drop the back seat and look towards the corner on each side. But overall, the fact that the system has no filter can be the reason you get that aroma in your van when passing by stink stuff.
When I'm coming into POS early in the morning, if I see smoke, I would normally turn off the A/C on the Beetham.