i have a 1983 300sd that only blows cold air. i have posted this issue before:

http://www.peachparts.com/shopforum/showthread.php?threadid=47808

i got a repair kit for the monovalve. i replaced it last night. the old valve did not look damaged- the rubber gasket didn't look like it had any tears in it, but i replaced it anyway. i did have a concern because according to http://mbdieseldiy.tripod.com/monovalve.htm
there is supposed to be a small washer, a wave spring, a large washer, a coil cylinder and an solenoid coil/valve top/electrical plug. well, when i took the old valve out the small washer was missing. no washers came with the repair kit- i got a new valve and a new wave spring. i put everything back together with the new valve, minus the small washer. (valve, wave spring, large washer, coil cylinder and solenoid coil/valve top/electrical plug- in that order) i can't imagine this small washer making that much difference- but maybe it does. at any rate, with the new valve- i still have no heat.

to try and get the heat to come on, i push the top fan button, the thermostat wheel is turned to "max" and i push the "ec" button. this is what i should be doing to get heat- right?? the heater hose (the hose that goes from the block to the heater core) is new. the hoses that are connected to the monovalve look good- no tears or leaks. when i unscrewed the 4 screws to replace the monovalve- after the 4th screw was loosened coolant began to seep out of what the valve is screwed to- only a little leaked out- but i don't know if this is normal or not.

it is getting colder and colder here- i need to do whatever i can to fix this problem soon. what else can i do? what else could be wrong? can i try and diagnose anything? any advice is appreciated. thanks.

nick