No antifreeze is "plain old ethylene glycol". All antifreezes have corrosion inhibitors. If they didn't you'd have serious corrosion within a few years or even a few months.

Traditional green antifreeze uses inorganic salts like phosphates and silicates and is called IAT (inorganic additive technlogy). GM Dexcool and most Japanese OE antifreezes use organic technolgy - OAT (organic acid technology), which consists or organic acids.

MB antifreeze and Zerez G-05 are are hybrids - HOAT (hybrid organic acid technology) - that use primarily organic technology, but have a small dose of silicates.

IATs provided good corrosion protection, but the salts precipitate out and clog radiator and heater core tubes over time. OATs don't do this, but there is some question as to their compatibility with tradional solders used in brass radiators and heater cores.

HOATs seem to be the best of both worlds and are considered "universal" because they are okay for cars that previously had the IAT type, and IAT types are being phased out of production.

Duke