Duo Valve

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shanksy

Active Member
Joined
Mar 20, 2009
Messages
397
Location
Andover
Car
W124 e220 coupe + W208 CLK430
I know the problems with the duo valve are well documented.

My 220 coupe was quite lightly specced so im not sure exactly what heating system I have.

I have the left/right temp dials and the fan speed and position dials but thats it, does this mean I have just a standard fan / heater or is it auto climate control based on the dials.

As I only get hot air, is the issue the duo valve regardless of what heating system I have?

Cheers
 
It's not definately the duo valve that has failed, could be one of many things. However, when they fail, they fail so that the heaters are stuck on hot so it is possible. I put the heaters on cold with the engine running and disconnect the power to the valve. When you reconnect it you can feel em jolt a bit as they jump into action, or they don't jolt because it's stopped workin. Still doesn't prove the valve is at fault tho, just proves it doesn't work!! Lol
 
I had a problem with one side only it was stuck on hot, I dismantled ( as per excellent instructions on this site ), both come apart at at the same time, cleaned them and it was fixed ie the left side that was sticking cleared. When they stick hot water flows so power opens them I think. It seems unlikely that both are stuck so I suggest you look at the power supply, can't help with that sorry. Peapod
 
If your car has Aircon it will have the 3 buttons in between the two main dials, these are switches for a dehumidifier, eco (turn off the air con ) and the recirculate option. I have pinched a pic off the net to show what I mean, another way to tell is that you will have two fans positioned infront of your radiator behind the bonnet grill. It sound as though your car is not fitted with aicon/climate.
Also note a nice retro fit early command fitted in the pic, not seen that before.
 

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cheers guys, have found the duo valve and have tried the tapping trick with no joy.

Will see if I can take apart at the weekend. The tutorial on this site looks pretty comprehensive.
 

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