DUOVALVE CHANGING - Help

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rana1

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Oct 4, 2005
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Anyone changed a Duovalve on a W210 ? can you provide any instructions please.

From scanning the thread it sounds like if one side is blowing cold and the other hot either on occassions or all the time then the Duovalve is faulty. Can it be cleaned up or does it have to be replaced.

Thanks
 
I replaced mine, but it is reported they can be serviced.

If you are going to replace it, then looking at the new one gives good cues as how it fixes. As it is at the top of the engines, you don't need to drain the system but a bit of water will come out. Make sure it doesn't go in the airbox. The top hoses are obvious, as they have clips. The bottom ones are not so obvious. There are two spring clips under the duovalve which pull out a short way. Then the valve can be pulled off.
When fitting the new one, it is possible to drop the spring clips. Eventually I tied mine on to something so I could retrieve them if they fell anywhere awkward. The duovalve is effectively a push fit back on, and is held in with the spring clips. Just make sure that it is pushed all the way on. Replace the hoses and the electrical connector. Run with the heater on hot for a while to get rid of any air.

Should take about 20mins, if you don't lose the spring clips down the back of the brake servo!
 
210duovalve.jpg


hth

guy
 
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Thankyou. I will get back once the change out has taken place.
 
Are you sure its your duo valves and not the temperature control wheels on the dashboard or the sensor in the sunroof housing.......my haywire heating turned out to be fluff and dust being stuck in the sunroof housing sensor. It works on a vacuum, ie sucking up air from the cabin, so they are prone to getting clogged.

Once cleaned my heating was back to normal......I only found this out after testing the Duo Valves with a voltmeter and finding that they were fine and then pulling out the temp dials from the centre console....the easiest item was cleaning the sensor in the sunroof housing. :eek:

Good luck
 
Guy

Out of interest, how long does the guide claim that this job should take
 

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