Troy, What you want is a phosphate-free antifreeze, which won't corrode your aluminum cooling system. BMW's is phosphate-free, and most American brands are not. However, an increasingly large number of American antifreezes are going phosphate-free, and at considerably less than $25/gallon. I think the one I've been using is Xerex 'ultimate' or some-such name (it comes in a silver gallon jug). Ian '76 M2002 '88 535is