Centre Vent Blowing Cold
 

I just finished replacing the evaporator on my 1995 E320. I thought that everything was working perfectly until this morning. It's been warm so the air has always been on. Today it's cold and the heater came on. What I noticed is that although there's heat coming from the floor vents and the 2 side vents, the centre vent is blowing cold air. Any idea what could be causing this? I checked each of the vacuum pods during reassembly and they all seemed to be working properly. I have the manuals on disk so I may have to reread the theory if someone can't help. Thanks for any suggestions. Bob

I think this is correct, you usually get a leakage of outside air from the center vents when its in heater operation. I think if you really crank up the temperature it will eventually send warm air through the center vents.

I believe this to be correct also. My 420SEL does that even though I wish it didn't. When its freakin cold outside my right hand is like ice when my left hand is nice and warm.

Thanks for the responses. I checked my manual tonight and theoretically the centre vent should be completely closed during the heating cycle. So maybe you've both got the same problem that I have with the flap not cycling correctly. I guess I can always close the centre vent manually so that it's not that cold:). Any other ideas would be welcome too. Bob