After searching Pep Boys, Autozone, and Kragen here in the San Fernando Valley CA, I found Zerex at Napa Auto Parts. I went to one Reseda and found a lonely G-05 bottle. The clerks asked me why I needed such a coolant (when they had cheaper coolants like prestone and whatevers). I love my car and I want to give it the best it deserves. Hopefully it lives long enough for my grandchildren....but hey! you never know right?

Anyway, my scenario is that I see there is green or yellow coolant in the tank. I want to give the cooling system a [citric acid] flush on the ol' 603. BUT, from what I was told, it's a different procedure on the 603. I looked at this DIY (Great pics by the way) at dieselgiant (I think it's a 240D).

http://dieselgiant.com/mercedes_citrus_flush.htm

My question is: Can I just take out the radiator and the thermostat and flush from the top radiator hose to come out the bottom? There are other hoses that I have to disconnect to get it out I'm sure, but I'd rather not fiddle with that stuff if I don't have to.

Can it be as simple as flushing the top hose (with the heater on) to go out the disconnected bottom hose?