Removing and cleaning heater control valve
 

Is it possible to: 1) remove the heater control valve solenoid without draining all the coolant and 2) is it possible to open and clean the solenoid itself?

SausageKing:confused:

What car are we talking about?

I found I could do so on my W210...I clamped the hoses.

They can be cleaned...but a lot of people who have tried found that, shortly thereafter, they were acting up again. I think I would rather replace than attempt to clean.

I'm assuming you're referring to the W123 platform. If so, you do not need to drain the coolant. I've attached a DIY tech article that will explain the whole process. Best of luck!

Mercedes-Benz W123 Heater Valve Replacement | 300TD 1977-1985 | Pelican Parts DIY Maintenance Article


-Dmitry

Sorry about that. A 1991 350SD, W126.

Sausage King

Yes, on the W126 it is very easy. It sits right up top near the 1st firewall. Unscrew 4 screws and on a cold engine, you will hardly lose a drop.

As has already been said, the W126 is painfully easy. While you have the valve apart, be sure to check for a torn diaphragm. I found my valve to be seized. Working it back and forth and cleaning it out with some water and detergent got it working again and has been working well all winter so far.