I don't know what the chemical content is but I was told it lowers the surface tension of the coolant so it makes it harder for small bubbles to form in the cooling water jackets so you get better heat transfer.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold