Green antifreeze or coolant as some call it.

The problem comes in when you mix different colors. Of course, it's not just the color, it's the chemical makeup and some can have bad reactions and turn to a thick goo like gel and it almost impossible to get it all out, if you mix the wrong colors together. MY advice to all my customers was to use the store brand universal. That way, "just in case" another color or type is mixed in later on down the road, either "by accident" OR "in case that's all you can find" in an emergency kinda situation, it does not matter, because the universal will mix with it ALL. Just my 2 cents and probably worth exactly that.