I changed the water pump in my 1989 260e this past year and used the green coolant initially. After approx 6 weeks I changed over to the MB coolant which was orange in color. I did this after reading some posts on this forum and at the advice of a local MB dealer tech. I've always used distilled water with the coolant. My question is that is the MB coolant the sam as the newer coolant called Dexcool (which is orange) that is used in the newer GM cars? I have been told that in older cars which have used the old green stuff should not use the mewer Dexcool type coolant because it can actually create sludge in the system. I'm told that they operate in different ways. Anybody got the low down on this?