Well this is what I did when flushing my system: #1 I bought Zerex G05 antifreeze because I read that this is the original antifreeze MBZ use. I drained the old stuff out via the hose at the bottom left (passenger) of the radiator, I have a 190E 2.6 so it may vary. Then I disconnected the 2 larger hoses on top next to the thermostat and drained what was in there. I then covered each with a cloth and blew inside to flush it out some more. Then I disconnected the hose that is connected to the hearter valve and made sure that was all drained out. I then proceeded to flush the coolant tank with distilled water and let it all drain out into a pan before I refilled the system with Zerex. Took me anout an hour. I also disconnected my coolant tank and scrubbed/cleaned it because it was filthy. I may do an upgrade to a clear one in the future as I still have the original rust colored one....which may or may not have been clear at some point. It is only about 9 years younger than me hope this helps. Oh...and you can buy Zerex G05 at Kragen autoparts or Google it.