Dash vents

[Ron]

Hi all, I'll reassembling a '66 230SL, which I purchased partially unassembled, and was working in the dash area.  I have 3 questions.

1.  I noticed the ducts coming to the dash vent are plastic and have a rectangular hole in them.  Looking up into the the dash, I see a hole in each one.  Is this correct?  Air will come out of these holes if they are not closed off somehow. 

2.  When I look into the dash vents, and open the vent door, I see some insulation just behind the doors.  It moves with the door, so I guess it has come loose in the ductwork.  Should I try to fix that, or leave it?  There's still space for the air to get by.  I've read where getting that ductwork out is a hassle.

3.  The little levers to open and close the vent doors were missing, so I have the new M-B ones.  On one side, the lever snaps in, and seems somewhat secure, the other side is loose and comes out rather easily.  Should I glue it in?  (These levers don't seem to be as rugged as on my '71 220D.)

Thanks,

Ron

[Anfinn]

Hi Ron,
I think the square duct you refer to is the fresh air supply to the large vents on the dash. It comes from the fresh air intake in front of the windscreen via channel integral in the bodywork to the square plastic channel that takes it to the outlet on the dash.
The joint between the bodywork and the channel has a foam gasket. The "door" does not have a seal on my car.

The round hole you mention, I think must be the supply of air that comes via the heater, and which is led to the small outlet on the dash next to the large one. You should look for a flexible pipe to take the air across the gap.

If you have a look at B Possel's excellent pictures from his resto, you will see this in the last photos from the May 25 2008 series.
http://picasaweb.google.com/mercedes280sl/May252008#

Regarding (3) I can only suggest that you check that the spring that holds the lever in place after it has snapped in, is bent to the correct position.

Good luck

[Ron]

Thanks Anfinn.  In the last picture of the sequence you refer to, I can see the little round hose from the heater to round outlet on dash.  That is in place on my car.  The square duct above it is where the problem is.  Look at where that little hose ends on the right, that is closest to the dash outlet.  Look above the end of the round hose and you'll see (perhaps) some thick black tape covering where my rectangular hole is.  Maybe that's access to the lever control for the fresh air?  And I just put tape over it?  Or a cover?

Thanks for your reply.  Ron

[Naj ✝︎]

Is this any help?

[Ron]

Yes!  Thanks Naj. 

In  your picture one can see the hole clearly.  It is below the rod.  So my question was, should that hole be taped shut?  Or is that to let air out into the foot wells?  Since the hole is closed off from air with the dash control, I'm thinking, now, that the hole is for foot well ventilation.

Also in the picture, one can look back through the open vent door and see the insulation in the air input duct.  I'll probably not try to glue mine back, given what I've seen on this site about how hard it is to take all this apart.

Ron

[Naj ✝︎]

Hello, Ron,
The footwell ventilation comes from the side pods on the central fan assy.
With the lower dash panels in place, I do not think there are air outlets on the panels to let air thru from these side boxes...

naj

[bpossel]

Hi Ron,

Dont tape the opening shut.  It is supposed to be open.  My guess is that the opening is for easy access to service the vent rods, but this is just a guess....  maybe access to lube the rod ball and socket for the vents?
Bob

[Ron]

Hi Bob,

I won't tape them shut, yet.  If it were designed to be open, that's the way I'll leave it.  Strange place for a hole, however.

Another thought.  My car only has the right side under the dash cover.  It has a 3" diameter hole under the duct hole.  Maybe fresh air is to come out this panel hole from the rectangular hole in the duct, and that helps to cool the foot well.  On the left side, the driver's side, I have the plans for cutting an under the dash panel.  On this panel there's also a 3" hole.  Maybe for the same function?

Ron

PS I have not driven a 230SL yet, mine is still apart.  However I used to have a 1957 "Bug Eye" Sprite, and the foot wells were like an oven, unless  you used the vents under the dash.  These vents were heater vents, but one could turn off the water supply to the heater, and the result was cool fresh air flooding through the foot wells.  Maybe that's what all these holes are for on the SL!

[gorgoo]

Old topic but I had the same question. And the answer seems to be "leave this rectangular hole open".
So my opinion is that the reason of this hole is to somewhat cool the footwell (the ones near the tunnel are for heating) and also to reduce the noise if you drive with vent flap open but with the chromed vent outlet in the dashboard closed, (or fully deflected).
Strange idea anyway.
Didier.