http://www.popularmechanics.com/how_to_central/automotive/1272436.html
How about just pouring orange antifre eze into every cooling system, say, yours? Sorry, but it's not that simple. The new organic acid antifreezes may be used only if the cooling system has an aluminum radiator (rather than copper-and-brass).
However, let's assume the reaso n you're thinking of a coolant change is because you're changing a cooling system part (pump, radiator, heater, thermostat housing) on a system with a conventional coolant, not an organic acid orange or pink. In that case, don't change to organic acid ora nge, even if the part you're installing is aluminum. Use a fresh fill of familiar U.S. yellow/gold or green silicated antifreeze.
The two orange extended-life antifreezes are compatible with each other, with what's factory-fill in GM ca rs and the '99 Mercury Cougar, and with the pink in VW/Audi cars. However, they're not compatible with a special orange antifreeze in 1998-99 Chrysler L/H cars (Dodge Intrepid/Chrysler Concorde and 300M), a special "hybrid" mix of organic acids and silicates. The green in most Japanese cars contains no silicates, so it's not the same as the green in the parts store. The yellow in some European cars contains some silicates, but it's very different from yellow Prestone, the top-selling U.S. brand. And then there is red antifreeze used by Toyota, and blue used on some European and Korean cars.
