W124 M111 (E220) Coolant flow diagram
 

Hey folks. I was wondering is there any way to find some coolant flow scheme? I have W124 E200 from 1993. I was searching on the e-net half a day trying to find some diagram shows me the exact coolant flow. My car has dual zone Aircon. system as well.
From that what I found so far I understand that the coolant flows from the engine head directly inside heating radiator (in the coupe) via a single pipe but exits via duo followed by a duo valves and then to the water pump. But where the coolant pass through when the valves are closed (AC is ON and this circle is closed) ?
It will be much easier if there is any diagram. :confused:
Thanks.

I dont have a diagram, but I would think that the coolant would simply not exit the back of cylinder head, and continue its normal way around the block and head until it exits back out the front, through the upper hose to the radiator. The way I understand it, cool water from radiator goes into the water pump through the lower radiator hose, from there into the engine block, then through the cylinder head and back out through the thermostat and upper radiator hose. When the engine is cold, the thermostat shuts so that water only flows around the block and head for quick warm up.
Pretty sure thats how it works.

Are you just curious or do you have a heater problem? In US MBs there's usually an electric auxiliary pump between the heater control valve and the water pump inlet. The '95 E300 Diesel is the only US model I know that has a bypass line from the cylinder head cabin heat source to the monovalve. For the rest coolant doesn't flow from the cylinder head to the heater core when the heater control valve is closed. The auxiliary pump only runs when the heater control valve allows flow.

Sixto
83 300SD
98 E320 wagon

Yeah I was just curious. I had few more cars (different brands) and this is the first model without a bypass. I just want to have some basic knowledge about my car. : )