If you are going to be working on your own car, then you might want to go over to the 107 forum here. There is a LOT of information and a lot of people. R/C107 SL/SLC Class - Benzworld.org - Mercedes-Benz Discussion Forum
There is sort of a 'procedure' for burping the cooling system; you sould put the front end up on ramps before you start the job, eight to ten inches should do. This has multiple benefits, it's easier on your back, you can get to the drain valve at the bottom of the radiator mre easily, it makes it a LOT easier to retreive dropped parts and tools, and it raises the front of the engine enough to make it easier to get water/coolant past the thermostat.
After you drain the coolant, replace or turn off the plugs or valves. Then fill the system through the reservoir and wait a minute or two, then top it again. Then start the car WITH THE PRESSURE CAP OFF. The coolant level should go down a bit, so top it off again. Then hold your hand around the small hose from the top of the radiator to the reservoir, it should start to get hot after a few minutes. Keep an eye on the level in the reservoir, brinign it up to the fill level as needed.
When the little hose is hot to the touch and the reservoir is at the full mark, you can put the pressure cap back on, back it off the ramps, and go for a drive. When you come back home, drive back up on the ramps, and repeat the process as necessary, AFTER LETTING THE CAR COOL DOWN.
NEVER OPEN A HOT PRESSURE CAP!!!!!!!
Hope this helps,