Quote Originally Posted by genphreak
... the wrong coolant is a very bad thing in a BMW. It sounds weird but is true. It doesn't take long to destroy a lot, they are very specific about it. Search for coolant and you'll see if you don't beleive me. Plain water is ok to run until you can get cool blue (BASF Glysantin coolant)...
I've seen this several times, here and elsewhere, including some who seem to suggest that you should only use genuine BMW coolant or (apparently) your engine will dissolve. I've also seen comments to the effect that any aluminium-compatible coolant is fine.

Is there something unique to BMW cooling systems that requires blue and only blue? I notice the Bentley manual says on page 170-6 to "always use genuine BMW coolant or its equivalent to avoid the formation of harmful, clogging deposits..." I would take "equivalent" to mean any aluminium-compatible coolant, as long as it's changed every two years. Yes? No?