This is the method I use for all my cars:

To flush, remove thermostat, reinstall housing, disconnect upper radiator hose at the radiator, and flush by inserting garden hose into radiator hose. Water flow should be opposite coolant flow during engine operation. Work the car's heater to flush that part of the cooling system also.

Flush overflow tank, then empty by siphoning off the fluid.

Once flushing is complete, turn off water and open all drain ports (block and radiator).

Reinstall thermostat, button everything back up, and refill with 50% antifreeze (calculated from your car's cooling system system capacity). Top off with water (preferably distilled). Use MB antifreeze from the dealer or Zerex G 05 antifreeze. Zerex G 05 is nearly identical to the stuff from the dealer, and is cheaper and more readily available at most auto supply houses, plus it is a product approved for use in MB coolong systems.

Tips:

If the coolant has oil in it, you should consider flushing with a non-abrasive and non-chlorinated detergent such as Shout, Spic & Span, or Dawn.

If the coolant is otherwise dirty, you should consider flushing with a citric acid-based flushant such as Prestone Super Flush.

Some people report that they run the engine a bit during flushing to help move all the old coolant from the engine.

Coolant is extremely toxic - and sweet. Keep your pets indoors if coolant is present outside. There have reports of horrible deaths to family pets drinking the stuff.

Dispose old coolant properly. Do not dump it on the ground, in the septic system, or in the storm drain that goes straight to the lakes and rivers.

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95 E320 Cabriolet, 169K