did my 190e today. my car had the "green stuff" in it. drained radiator,attached backflush connection to hose from firewall to engine that goes over oil filter, removed thermostat, re-installed housing, removed cap on tank, attached a hose to where the cap was,turned on water and started engine.. i let it run for about 15 minutes after the water was clear. i refilled with zerex g02.( poured in thermostat housing first, then replaced thermostat.put everything back and was surprised to find that now, when the ac comes on, both fans start at about 85 degrees c. before, no fans came on until about 95 degrees c( i have installed 1100ohm res per prior thread). the only problem so far is that even tho it says color has been added on the label the zerez 02 looks like water and you cannot tell what the level is. time will tell!