W126 Monovalve eliminator – part 3

I have been working on a project to eliminate the monovalve from the climate control system in my 560SEC. In the last part I had almost completed the cooling hoses required for the job. I had mostly worked out hose routing I was looking for – which was combining the dual outputs from the heater core into a single hose where I could place the new heater valve.

Looking further my design wasn’t going to quite line up. Once I put the elbow piece on the end, it was too long and the hoses were bent too much. I didn’t […]

W126 Monovalve eliminator – part 2

My 560SEC had been leaking coolant and giving me heat when I didn’t want it. Last week I started the repairs for these problems. As the Bosch and Mercedes W126 Monovalve repair kit was no longer available, I have been installing the Klima Design Works monovalve elimination kit.

In the first part I removed the W126 monovalve, auxiliary water pump and other hoses. This gave me the room to give the area underneath the heater hoses a good clean. There were some leaves and other detritus. Its important to remove this stuff it can cause rust. The mud stays wet […]

W126 Monovalve eliminator – part 1

My 560SEC has been having a couple of problems with its cooling system. Coolant has been weeping out of the top tank of the radiator. In addition, the monovalve has failed, causing unwanted heating at idle. The radiator looks either original or replaced very early in the cars life. As these radiators have plastic tanks, I have purchased a new one to replace it.

It used to be possible to purchase a monovalve repair kit from Mercedes or Bosch. The supply of these has now dried up. There is a kit from a company called MTC but all the Mercedes […]