It was not really the dexicools fault per say, it is GM's. The problem
lies in the increasing presence of aluminun with the cart iron in the
engine assembly which increase reactivety with water in coolant. A 50/50
mixture will not cut it and GM came up with Dexi to try to stay with
50/50 to save money on coolant on production line. I have a few vehicles
that have had dexi in them for over 5 years now and they are all fine
and coolant and overflow tanks are a clean as day one but they are also
running 60 to 70 percent dexi too. Even Mazada recognized the problem
when they came out with the rotary engine long ago and called for a
90/10 mex (anitfreeze to water) in their early rotary engines that had a
lot of aluminum in them.