Mercedes-Benz Forum banner

1 - 20 of 98 Posts

·
Registered
'01-E320 & 02-ST2
Joined
·
31,633 Posts
Discussion Starter #1 (Edited by Moderator)
Hey, folks.

Since the directions to R&R and clean the duovalve are spread throughout a few threads across this forum I thought it would be useful to put them in one single post that we could sticky for the DIY thread.

Credits to: wood'sbenz, raymond- and netdvn for the following information:

Before starting, here are a few tips:

- BE SURE not to break off the small wiring attached to the gadget.
- BE SURE to pack towels beneath the duovalve to soak up spillage
- BE SURE not to drop screws or parts when removing and installing

The duovalve is located on passenger's side in the engine compartment. It is easy to spot as it has two small cylindrical aluminum cylinders. There are 5 torx (I think t-10) screws holding it together. With the car COLD, remove these torx screw (use a magnetic drive so as not to lose a screw). Leave the electrical connection alone. Once the screws are removed, gently remove the aluminum cap of the duovalve - pulling straight up - you may need to use a thin/flexible putty knife to GENTLY loosen it at first.

(When reinstalling, the two small screws in back side are tight clearance so you can use painter's tape and poke a hole for the screw. Before it's fully tight, tug on the tape and rip it out.)

After you remove the aluminum cap, you'll see two plungers in the lower portion of the valve. Gently remove the plungers, dry and clean them with a clean rag - you can use carb cleaner if they're really funky. Once cleaned, lubricate the lower portion of the plungers with some Vaseline and put everything back together.

(Greg's note re: lube... I haven't done this but I think that plumber's silicone grease would be more effective for lubing the plungers, not petroleum based, thinner so it's less likely to impede actuation of these little things, lasts longer, etc.)

netdvn's pics from the longest AC thread in this forum are seen below. Note that in this case he cleaned the duovalve with it installed in the car. If you're going to do the DIY fix from gt4rcdude then it's probably easier to remove the duovalve (personally I think I would remove it to clean it, less likely to drop things, etc.).


.

.

.
.
.


[ADDITIONAL INFORMATION] The 1997 E420 (210.072) duovalve is COMPLETELY different, and cannot be easily dis-assembled for cleaning / repair. The same valve is also used on the 1998-1999 E300 turbodiesels (210.025) and CDI (210.026). More details in this thread:

http://www.benzworld.org/forums/w210-e-class/w210-e-class/w210...nary-tale.html



Thanks again to all who contribute to this forum, it helps so many.

Take care and enjoy the ride,
Greg
 

·
Registered
W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
Joined
·
814 Posts
My duovalve looks different, where do I lube the plungers, the section inside the springs? Thanks!



 

·
Registered
W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
Joined
·
814 Posts
Anyone can give answer to the question where to lube the plungers of 1996 E320 duovalve, the cone, the shaft or the spring? Thanks!

 

·
Registered
91 560SEL(RIP),98 E320matic 230k baby!,98 C230,93 500Ehurt,Rover crawler,97 Vulcan,01 R1,02suzukiTLR
Joined
·
55 Posts
I managed to do mine today at work. After listening to everyone else I was so careful and knew what to expect I did not loose anything and I did not have to cover the body cracks and crevices. I did however draw blood from my thumb trying to unplug the connector, boy your fingers have to be tiny to reach down in there. After 30 minutes of trying and nursing my injury I then realized that the connector does not have to be unplugged. Here are some pics for future reference so folks can see different views of what it looks like and how the electrical connector does not have to be unplugged.
 

Attachments

·
Registered
2003 Mercedes Benz E500
Joined
·
668 Posts
Hey, danboy...

You might want to check on the type of coolant in your car... The pic looks shows the looking pretty "greenish" and the correct coolant has a golden/amber hue.

JR
 

·
Registered
1996 210.020
Joined
·
3,972 Posts
There is only one duovalve, and it regulates engine coolant flow through the heater cores.

Set the temperature control to "LO" on both sides and turn off the AC compressor by pressing the EC button and turn the fan on low. Then measure the air temperature at the dash vents on each side.

Under these conditions, if one side is hotter than the other, the problem lies in the duovalve or the pushbutton unit.
 

·
Registered
1998 Mercedes E320
Joined
·
266 Posts
Ok so I cleaned the duovalve, but I'm still getting error code
B1226
B1231
I haven't checked the diverter flap because I don't know where it is. Plus could someone tell me where is the "firewall."
 

·
Registered
1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
Joined
·
6,019 Posts

·
Registered
1998 Mercedes E320
Joined
·
266 Posts
Well, after cleaning the duovalve, the air still doesn't come out from the right vent as strong and it does from the left vent. Do you think this is an indication of the blower regulator malfunction?
 

·
Registered
1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
Joined
·
6,019 Posts
Duo-valve would be indicated when temps

were far apart.Air flow could be a stuck flap.Check your pse.
ohlord:bowdown:
 

·
Registered
2001 SLK 320(217K Miles), 2002 E320 Special Edition(183K Miles)
Joined
·
3,467 Posts
It's normally covered up - the photo is with the cover removed.
 

·
Registered
1998 Mercedes E320
Joined
·
266 Posts
thanks guys, the picture is great for identification. So I found it, but when you said "check the PSE," what am I suppose to do when I find this thing? What are the things I'm suppose to check?
 

·
Registered
2002 MB 320e 97,000
Joined
·
37 Posts
I have the same duovalve as you have. I am getting the Eb1416 error code. Did you find out where or how to lubricate the plungers? Did you fix your problem?
THanks
 

·
Registered
2002 MB 320e 97,000
Joined
·
37 Posts
texholdem, I have the same duovalve as you have. I am getting the Eb1416 error code. Did you find out where or how to lubricate the plungers? Did you fix your problem?
THanks
 

·
Registered
210.065
Joined
·
2,947 Posts
Last time when my compressor is down, it also showed code b1416
 

·
Registered
210.065
Joined
·
2,947 Posts
But now I have 1416, not sure it's new or old. I need Greg's code reader.
 
1 - 20 of 98 Posts
Top