Does the heater core valve shut off completely?

[ncsurfer]

I pulled the heater core out and discovered two additional valve stops under the heater core.(see second pic) The valve stop that was on the valve looks like the number "6". I took the core to a shop with the valve out, and had it checked for leaks and obstruction. No problems there. I also had the plate re-attached at the same time. I then put a new O-ring on the valve and I used the different valve stop that I found under the heater core because it matched the one used on http://www.sl113.org/wiki/Electrical/HeaterControlValve?
and positioned it and the heater linkage as described in the Tech Manual. I took the heater core with the repaired valve, the different valve stop and heater linkage installed, back to the shop to test for leaks from the new O-ring. There were no O-ring leaks. But when we turned the valve linkage to the off position, we were still getting a small amount of water passing through the core. I questions are:
1. Is the valve designed to allow very little water flow in the off position or to be completely off?   If the answer is completely off, then:
2. Have I put the different valve stop on backwards?
3. Should I reuse my other valve stop that was on it?
Thanks......

[ncsurfer]

Here are a few more pics

[ncsurfer]

2 more pics

[Jonny B]

Most interesting. When we took the heater core out of my friends car, there was not "no 6" type stop. It was the type as you indicate you found in the heater, and the top attachment for the heater control rod. The "no 6" type stop must have been a recreation previous owner kind of thing? The item with the tab (as you found under the heater core) is what we put back in. The core valve is a control of flow type set up, and should, I am guessing, stop the flow when turned completely off. The tab under the control lever tab limits the movement so that the heater level (connected to the red control disc in the heater control unit) cannot over-range. Will be most curious to see what others have to type.

[ncsurfer]

Yes, me too. I only want to do this once.......

[Jonny B]

Keep in mind, the top of the heater valve is accessible once everything is put back together, so it is not as much of an issue with changing the little stop. The major thing is to ensure there are no leaks from the core. You can even change the heater valve o-rings from the top, you just need that piece of string!

[ncsurfer]

Yes, I know I can do it with the core back in, but it is easier right now to turn it over and test to see if that stops the the small water flow...... I am going to do it this weekend.
Thanks......

[ctaylor738]

I think a mechanic or hobbyist was replacing the o-ring and dropped the little lever.  Following Taylor's law (the smallest part falls into the darkest and most inaccessible place), the lever fell down under the heater core.  Needing to get the repair done, a new lever was fabricated.

[ncsurfer]

Chuck, I think you are right. I knew the owner before me and he could do anything he set his mind to.  A real Renaissance man. He raced and restored cars, owned and flew his own airplane. I was told that instead of paying someone else to do the annual, he studied for the exam to be certified to do his own annuals and passed the first time. So yes, I can see him knocking out this little part in no time.....

[Benz Dr.]

The 190SL valve, which is slightly different, has a small slot milled into one side of the hole so that a small amount of coolant will bypass even with the valve shut off. The 113, by comparison, should close off completely with little or no bypass. I try to set everything so that the system will shut off completely with the dial at zero heat. As much as I want heat when it's cold outside, I want cool air even more in the summer heat. After a lot of adjusting, I finally got my car to work perfectly in hot or cold weather conditions. My heater will get so hot I often have to turn it down once the engine is fully warmed. 

[ncsurfer]

Today I turned the valve stop over and reset it. When I applied air pressure in the pipe, there was no air leaking in the system! So, it fixed the slight leak. Thanks everyone for your input. Steve