My duovalve looks different, where do I lube the plungers, the section inside the springs? Thanks!

 

The driver's side was getting warm, cool on the passenger's side. I did the work yesterday. My duovalve looked similar to the above. It was easier to work with the connector removed. To remove it, I pressed the sides of the connector then gently lifted it out. Lining the well with paper towell to prevent losing screws was a very good idea. I did drop a screw but it got nowhere to hide.
I cleaned the rust and "gum" on plungers with rubbing alcohol then let them dry. I did not need to lube anything. I think the slippery coolant will lube everything inside. Putting everything back, I ran the AC but the driver's side was still warm. I removed the duovalve again. The engine was just little warm, coolant was pushing out. I uncapped the coolant reservoir, the coolant stopped coming out. I reseated the duovalve, put in the 3 screws near the firewall but not yet tightened, press the opposite side of the duovalve to see if the springs spring up the duoavalve a little to ensure the alignment, put in the remaining 2 screws, crisscrossing tightening the all screws. I noticed that the screws needed to be turned (not so hard) until they could not be turned anymore to ensure no leak. AC diagnosics showed 14 on sensor 7. I put in a little freeon to reach 15. Now I can drive in today's 105 degrees in LA without sweat.
Thanks for all tips.

 

Anyone can give answer to the question where to lube the plungers of 1996 E320 duovalve, the cone, the shaft or the spring? Thanks!

 

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.

 

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

 

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.

 

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."

 

Did you

run How to Diagnose Air Conditioning Malfunctions | EclassBenz.com
write down the values and errors and clear the errors?
firewall is the bulkhead that separates the engine bay from the passenger compartment.
:bowdown: ohlord

 

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?

 

Duo-valve would be indicated when temps

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

 

what's a PSE? and where is it located under my hood

 

your PSE is under the back seat next to your battery. Here is a pic

 

It's normally covered up - the photo is with the cover removed.

 

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?

 

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

 

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

 

b1416 refers to the auxiliary water pump.

 

Last time when my compressor is down, it also showed code b1416

 

Hmm... that should be a b1419.

 

But now I have 1416, not sure it's new or old. I need Greg's code reader.

 

ILJ, would it help with Euro spec cars (as maybe yours is)

 

^^^^^ What he said, if you have the pushbutton HVAC system, then use the GREAT built-in diagnostic that is explained in the stickies.

 

I tried to press and hold both Autos and then the code reappears. So now I must check the coolant circulation pump.

 

Sorry Matt, how do you check the coolant circulation pump?

 

Now that's a very good question. It would be nice to have a pair of connectors so that you could easily wire a meter into the line, but that's a bit much to ask most times. What you want to know is the current demand from the motor. I don't know offhand what it should be, but not a lot more than one amp.

 

Thanks Matt, is the motor always on, or should I check when temp >80C?

 

It's not for cooling the engine, but for heating the interior. Turn the car off and hit the REST button.

 

Thanks Matt, when I turn off the car and hit the rest button, the side vents blow again, not that warm though. I have the following questions.

1. I know duo valve DTC should be 1417 and 1418, but could the duo valve blockage cause DTC 1416? I am hoping it can because this is an expensive part.

2. When I remove the aux coolant pump for test, should I clamp those 2 hoses or just let the coolant flow and add back some later?

3. Any tricks on removing the clips/clamps on the hose? Do I have to break them?

Thank you.

Just for reference:

 

I had that pump bad on W210 and it is using magnet as a clutch. Meaning frozen pump will not freeze the motor. I know that the recirculating pump in ML runs some time after turning off the ignition to eliminate "hot spots" in the engine. Haven't notice that in E, but after being married for more than 1/4 of Century I don't hear everything anymore.