I don't think this description is entirely correct, tho I could be
wrong.

The air vent in the door has nothing to do with allowing fresh air into
the van, it only allows air out so that fresh air can come in through
the dash vents.

I guess it's possibly different for US spec models, but I doubt it.

The ductwork for fresh air ventilation does go through the doors, but
does not connect with the vent in the door.

From the doors, the ductwork goes up the door pillar and overhead, where
there are vents on the sides of the roof for rear passengers.

However, Westfalia versions only have the rear roof vents on the
passenger side.  The ductwork through the door on the driver's side is
blocked with a screwed-in plastic panel forward of the door (on the
windshield pillar).

I don't believe that this ductwork goes into the engine compartment to
be used for heat, especially since I can still get the same amount of
heat with or without the fresh air lever on the dash in the open
position.  I believe the fresh air for heating enters the van through
the cooling air intakes at the rear of the van and then is forced by the
blower on the alternator into the heating system.

Sean

>
> I guess, you're all waterboxers...
>
> The air channels, coming from the front air inlet, are
> going through the door, where the first fresh/cold air
> vent is placed. Then the ductwork goes up to the overhead
> frame rails. In the Bus option of the T3 you got fresh
> air vents left and right at the overhead frame rails.
> At least this ductwork turns down to the engine compartment.
> There it is attached to the alternator fan which pushes
> the cold air through the heat exchangers at the exhaust
> system. The hot air goes through a paper duct below the
> van to the front. There is a small outlet in front of
> the middle rear seat. The paper duct goes up where the
> radiator is at the waterboxers.
>
> Why are this channels taped? I guess, it's just rust
> prevention for the upper frame rails. The fresh air
> is not needed in the engine compartment.
>
> Helmut
> '80 Camper
>

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