240D Cabin Air Recirculation
 

Does anyone have working air recirculation in his or her 240D or a similar old Benz with manual climate control? According to the manual, when the blower is turned off the cabin is supposed to be insulated from dust and "offensive odors", but this has never worked for me. Not only do odors come in at any time but I can feel the air coming in through the vents at higher speeds even with the blower turned off. I'm wondering if something is not working or if this is just how it was intended. Overall it's a fairly good and reliable climate control but one thing that's sorely missing IMO is a simple recirculation button or lever.

Mine does not have it. When I open the center vents on the highway, I get a nice low breeze without the fan.

In my experience, the outside air does not come through the vents with the fan off and the sliding control for outside air closed. I think this is true because the few times I have run the fan, the dust plumes are huge. This tells me that unless the fan is on or the outside vent is open, no air is coming through. The only time I run the fan is in the winter. I only run the a/c when I think I'm going to die because it just kills the little bit of pickup this yellow beauty has when starting out from a light or stop sign.

Kevin
1979 240D manual
1984 190D manual

At highway speed I get a breeze from all open vents (with the blower off), especially from the center ones. Is this how you guys have it too? If in doubt just stick your hand in front of each vent. I wonder if there's a flap behind the glove compartment box or somewhere that's supposed to restrict air from coming in and it's not working. Does anyone know?

The only benz I have had with recirc afik is my 91 350sdl.

Tom W

As I understand.....
 

Please bear in mind....this is how I understand the Automatic Climate Control workings......not sure about the manual version.....but I would assume that the thinking behind the design would be similar.......

there should always be some air flow from the outside.....passing thru the vents in the dash.....and exiting out via the louvers (for lack of a better word) that are located under the chrome/aluminum flashing just aft of the rear doors in the "C" pillar.....

SB

That is true for your 85.

The later cars carried a recirc button...possibly not a 100% recirc. I always felt it was but I may be wrong. I used it when coming up behind an old pickup or van where I expected those nasty fuel waste fumes.....it worked pretty well.

Tom W

The automatic climate control of the same era should work the same, at least according to the owner's manual that I have. I also used to have an '82 300D (with the automatic CC of course) and the air shut off feature with the "off" button worked better than in my 240D, but there was still some leakage. I'm tempted to pull out the glove box from my 240D and see if there's a sticking flap or something. I'll probably do that sometime this weekend.

As far as an actual recirculation button is concerned, I think MB didn't put one in the cars until the '86 model year... a very useful feature on congested highways and streets if you ask me.

My problem is exhausting odors from the inside of the car to the outside....:o:o:o

So the problem is a gasser?

Tom W