another dumb question

[ewenjo]

Okay! Why is there an inlet hvac duct in the doors of a "82 SL? There is no apparent outlet. So what does the cool / hot air in the door do?

I have enough issues with the AC without having some air ducted to a door!

Thanks for an intelligent reason.

[dpetryk]

It keeps the inside of the doors dry in the winter when moisture can freeze on the glass and other parts inside the doors. Also makes the door warm so you are not sitting next to a door that is -20f in winter. Its a comfort thing. Remember that car was designed to withstand some tuff winter conditions. Same reason that the washer fluid is heated in the 126 series vehicles. To make things work better in harsh winter conditions.

The duct to the door should never "be an issue". Not much to go wrong with it.

[ewenjo]

Thanks deptryk

That's what I thought..then of course one starts thinking. Where is the outlet for the incoming conditioned air? For circulation..flow in must equal flow out. I suppose the door design is such that it just leaks out around the seams. Okay. Now cooling air in a hot door will cause condensation within the cavity. Doesn't sem to be a good thing. The hot air in the winter may be a plus... oh well german engineering.

[Walrus]

Originally Posted by ewenjo

Thanks deptryk

That's what I thought..then of course one starts thinking. Where is the outlet for the incoming conditioned air? For circulation..flow in must equal flow out. I suppose the door design is such that it just leaks out around the seams. Okay. Now cooling air in a hot door will cause condensation within the cavity. Doesn't sem to be a good thing. The hot air in the winter may be a plus... oh well german engineering.

You need to remember, the cooling air has had the moisture removed, and is fairly dry, compared to ambient. In the winter; however, the warm air will be moisture laden and the door skin cold. Then I could imagine condensation; however, the air tends to be drier (lower relative humidity) in the winter...

Also, I do not know when MB started it, but the 88 107 has heated windshield washers as well...

[dpetryk]

Those ducts only have flow when the heat it on.

[Walrus]

Originally Posted by dpetryk

Those ducts only have flow when the heat it on.

perhaps you're right on a '82... I should pay a bit more attention. After 1986 the following applies:

[ewenjo]

thanks guys

but...........

cold air even with moisture removed will cause condensation when it is introduced into a warm / hot cavity. if the air is continually flowing it will eventually dry out. But where is the out flow??

With regard to the "depetryk" comment that the ducts only work with hot air. My duct blows coolair. Perhaps my system is not working properly. Is there a schematic of the system available?

[dpetryk]

I was wrong. The vents do provide air regardless of the heat / cool mode.

Sorry for the mis-information.

You are worried about the outflow. Its everywhere!. Holes, leaks, gaps, the door is far from airtight. It leaks everywhere it can.

[ewenjo]

I guess we beat this to death! I'll live with the ducted air to the door cavity. Thanks Dave and others