I don't know how many of you all read Car and Driver. A while back they had an article on Antifreeze. Must have been between 1 and 2 years ago. But they were talking about a new type of antifreeze that had a different color and a completely different formula. Supposedly used stock on some exotic new cars. I don't remember all the particulars, and my old issues are buried in the closet, so I'm not going to check. But the gist of it was that you can't mix the two colors (ie new and old types) or else something bad will happen. Not sure what it was, something like either your radiatior ruined or messed up something. I think that is what Kurt is thinking of. Someone on here is bound to know the articles I'm talking about. I think Patrick Bedard or something like that wrote them.