Mercedes w126 heating problems

Page may contain affiliate links. Please see terms for details.

Pfinix

New Member
Joined
Mar 22, 2013
Messages
26
Location
Staines Upon Thames
Car
420 SEC
Hi There,

I have problem with heating in my 1989 mercedes 420 sec, is constant heating.
I search a little already and looks like it is a monovalve, and now is a question for all you w126 gurus out there, what is your suggestions to solve this issues (maybe it is something else), and second question where is located this valve.

Thank you in advance for your attention to this matter.

Regards.
 
Yeah it'll probably be that. Do you have a monovalve or duo valve? It depends on which heating system you have. Two dials for temperature or one.

Here is a link, I just put in monovalve in Google. Super easy to change, it is easy to reach in between the two firewalls, but where to get the part. Some aftermarket parts have been found to not work at all. You can pop it out to inspect the rubber diaphragms which will probably be split.

http://mbdieseldiy.tripod.com/monovalve.htm
 
Thanks for quick reply

I found the valve inserts A0008350644 £142.56

I'll check today afternoon, what type of valve is on my car.

Thanks for help.
 
I checked just now , and only left side is blowing constant hot.
I also checked it is a duo-valve, and on the one of the coil the rubber is damaged.
New valve
A1268300084 £428.76


Regards.
 

Attachments

  • WP_20160811_17_42_24_Pro.jpg
    WP_20160811_17_42_24_Pro.jpg
    102.8 KB · Views: 24
  • WP_20160811_17_42_04_Pro.jpg
    WP_20160811_17_42_04_Pro.jpg
    86.2 KB · Views: 28
  • WP_20160811_17_41_23_Pro.jpg
    WP_20160811_17_41_23_Pro.jpg
    127 KB · Views: 27
I checking now, the monovalve inserts (magnets), are ok with douvalve , still 2 x £142 in not a £428, the looks the same, but I digging the internet and I can't find the answer.
 
Another discover today, no power on the one side of the plug (one side 13.5 another side nothing)
Any ideas?

Thanks in advance.
 
I bridged the plus on the plug and working perfect , now I have a single zone climate control, the driver side temp selector control now both sides.
 
Suspected passenger temperature selector A1268202410 - £122.04 new ordered from MB .
 
Another new discover today, the climate control not working, Regardless of temperature setup, blows cool air, except if the controls are on max then blowing hot (really hot)
 
So finally i solve the issue with temperature. It was a temperature regulator placed behind the glove box.
Costs:
Duo Valve: A1268300084 - £430
Temperature selector (left) - ​A1268200103 - £150
Temperature regulator - A1268208510 - £ 350

Right temperature inside the car - priceless :)

Thanks again for help

Regards.

Useful link:

http://mbfans.me/EN/mercedes/parts-catalog
 
Last edited:

Users who are viewing this thread

Back
Top Bottom