I hesitated to post this, but decided that the issue deserves another visit. My 85 380SE is soon to be put into winter storage, so I have coolant on my mind. My concern is mainly with corrosion and freeze prevention, but I realize others living in more hospitable climes might pay more attention to the lower boiling temps afforded by a proper water/coolant mix.
I did the search, and have concluded that: (1) all the 'enlightened' on this board, or 98% anyway, recommend MB coolant over the 'green' stuff, (2) Valvoline Zerex G-05 is as good as MB's coolant, and (3) whatever it is, MB/Zerex/green, it's a good idea to flush and change it every 2 years or so (not the 98% agreement here though).
OK, so here's what I don't understand. What makes an older Mercedes engine so special that the green stuff isn't good for it?
It seems to me that there are lots of engines out there that are mostly cast iron with some aluminum parts like the rad and water pump in which the green stuff works just fine. Providing the recommended flushing and change is done, it strikes me as silly to be running around looking for MB or Zerex coolant when a good quality regular coolant should work just as well.
Is it just for newer engines with aluminum heads or whatever that his applies to, or is there some objective basis for this anti-green mania?

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1986 560SL
2002 Toyota Camry
1993 Lexus