W210 duo valve

Charles Morgan

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Olly having done my evaporator, the air-con is now delightful. However, one problem remains. In a seemingly random way the right hand side vents (driver's) would start blowing hot air without any regard for the dialled in temperature, which was always warmer than the left anyway.

Olly suggested it might be a stuck duo valve, so using the description on Benzworld on how to take it apart and fix it, I dismantled it and discovered the problem.



One of the plungers was sheared off - by the look of the metal some time ago (hooray not my fault!) so it looks like I need a replacement duovalve (or at least the part containing the plunger, as the top bit is stuck in there.

I am rather pleased to be able to diagnose the problem, now to source a replacement one.

In the meantime, any suggestions for keeping the plunger in the correct position to prevent the heating coming on - despite the weather, I can live with the heating off, but I hate being blasted by hot air!
 
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Charles Morgan

Charles Morgan

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Well, leaving the broken plunger out just ensures hot water will flow into the heating, so I need to work out a way to keep it down without blocking anything.
 
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Charles Morgan

Charles Morgan

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You normally are Olly!

Decided to leave it having had the pleasure of retrieving the good plunger which popped out into a crevice to the side. That was fun. Oh and one of the bolts holding it all together sheared going back in, so I decided as the little plunger had done an ok job of keeping the warm water back albeit randomly, I may as well leave it there until a new unit is sourced.
 
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Charles Morgan

Charles Morgan

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Thanks Olivier. A good idea in theory, the problem is the person who would be doing it - I haven't the tools, the skill or the brains to get it right.
 
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Charles Morgan

Charles Morgan

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Checking I find he has one on Ebay. Easy peasy.
 

Olivier

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Call him directly, might be a wee cheaper?
 

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I think I may have a second hand one that I can sell.
 
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Charles Morgan

Charles Morgan

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I'll hold off ordering one then Olly.

We could fit it and get the rear wiper going at the same time!
 
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Charles Morgan

Charles Morgan

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Olly has found one so I'll have even more fun fitting it. Oh dear..
 

coupe deville

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I have an old leaky124 one, but the plungers are ok, If its the same I could send you one of the plungers in a jiffy bag, no charge for a fellow 124 enthusiast, even if you are fitting it to a 210 :rolleyes:
 
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Charles Morgan

Charles Morgan

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I think they are different Coupe deVille, but as the end of the old plunger is stuck in the unit I'll have to replace the whole lot anyway. Thanks very much though!

(think of the W210 as the W124 with better engines and gearboxes, and likely to be much rarer because of the rust!).
 
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Charles Morgan

Charles Morgan

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Update - old duo valve removed, new (secondhand) one bits fitted, still knackered and internal temperature wheel on the right fluctuating badly, so ordered new one and new bits for the controls. Fitted next week. It behaved on the way home though, nice and frozen, then went steaming hot on a later drive.
 
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Charles Morgan

Charles Morgan

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One brand new duo valve, :( fan regulator :eek: and aircon control panel :doh::wallbash::mad: later..

Nice and cool drive home though :cool:

Olly remains highly recommended. Sometimes I wish I owned a car built by Aldi rather than Mercedes though..
 

DSM10000

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One brand new duo valve, :( fan regulator :eek: and aircon control panel :doh::wallbash::mad: later..

Nice and cool drive home though :cool:
Hopefully your misfortunes with your fleet will now be at an end for some time!

At least you may now enjoy the summer warmth in cool comfort :cool:
 
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Charles Morgan

Charles Morgan

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Fingers, toes and genitals crossed..
 

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