PeachParts Mercedes-Benz Forum - View Single Post - W124 Climate Control Vacuum Valve Repair DIY

Jeremy5848 · #27 06-27-2013, 12:04 AM

Quote:

Originally Posted by freesoul

Resurrecting an old thread- I have a problem with my 95 W124 that I am getting heat as well as A/C. The center vents don't open, tonight I stuck a pen in and forced them open. Now I am getting cold air there plus a little heated to the one side.

Here is my heater valve in the engine compartment- its been leaking since I've had the car 3 years ago LOL, could that be part of the problem?

Is your 1995 W124 a diesel? (The gasoline version uses a slightly different monovalve.)

The leaking monovalve might be part of your problem. I've been investigating this problem since mine started leaking in January. A replacement is $500 so the best solution seems to be to get a "radiator patch kit" (Fiberglas® cloth + Epoxy glue) and make a repair. I'm about to try that -- others have reported success.

I've reported the problem to my dealer who has sent word to the factory in Germany -- whether they'll listen is another matter. This combination monovalve/aux pump is unique to the 1995 E300D except for a very few late-1993 300D-2.5 Turbo engines. Since all are now 18+ years old, I doubt very much whether Mercedes really wants to do anything about it.

If your monovalve is not closing completely, it could be allowing hot coolant into the heater core even when the a/c is running. That could give you hot and cold air. It sounds like you also have a problem with your vents, which could be one or more of the vacuum actuators that open the flaps. SOme of the vacuum actuators (they have rubber diaphragms that can rupture) are easy to get at, others require pulling the dash. This is not a terribly difficult job but it takes a fair amount of time -- there are a couple of good DIYs here somewhere.

Jeremy