Well I finally tracked down the cause of my dissappearing coolant on my 1989 190e 2.6.
It seems the hose from the upper rear of the engine has a small hole in it near where it connects to the engine. This hose then goes through the firewall.
Does this hose connect to the heater core? If so, would it require removal of the dashboard to replace it?
Any help would be appreciated.
The car car is currently for sale so I would rather not pull the dash to fix it unless I really have to, any ideas?
Sorry I don't have pictures, but looking under the hood it's at the very rear of the engine just several inches below the valve cover coming from the right hand side. Approx 3/4" dia. It has a couple of 90 degree bends before going throught the firewall.

Thank you

Paul