To the best of my memory the 116 and 123 servos are identical except the mounting location and likely the mounting bracket (not the mounting holes on the servo).

I gave my 116 servo away before I picked up my 79 wagon so I couldn't compare them directly.

I had always assumed the electrical "upgrades" were good deals. I have had no personal experience with them but you say they are junk? What is so bad about them? I almost pulled the trigger on one on eBay a couple years back.

I've been through 3 servos. All were used and all leaked in under a few thousand miles. One plastic and two aluminum. Maybe I have really bad luck? One was shaped a bit different (shorter) so perhaps one was a 116 servo? Either way they all hooked up the same. I finally just bypassed the coolant flow from the servo and put a ball valve in there in case I need heat (I only drive my wagon in the summer). I just keep it closed in the summer.

If it didn't leak so darn much I would agree that it is a good system. Plus I am in the middle of swapping in a turbo engine from an 81 TD and am considering doing a full climate control swap as well.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD