(Dyes to distinguish types
Types of Antifreeze: http://www.eastcoastrollingthunder.c...hp?topic=808.0
•Conventional - Green/Yellow antifreeze contains silicates, phosphates and / or borates as corrosion inhibitors to keep the solution alkaline. This is called Inorganic Additive Technology (IAT). European car makers like VW specify coolant additives lacking in phosphates and including borates and low silicates because their water is harder and it reacts with phosphates to create aluminum phosphate or calcium and magnesium deposits.
•Organic Acid Technology (OAT) or Extended Life Antifreeze Coolant (XLC or ELC) antifreeze contains neutralized organic acids (organic acid salts) that protect engine parts from corrosion. These include Havoline® XLC, GM's Dex-Cool® (also manufactured by Texaco) and VW's G12. Honda has an extended-life OAT coolant that is dyed dark green and does not contain 2-EHA. OAT includes such ingredients as sebacate (Toyota & Honda), 2-ethylhexanoic acid (2-EHA) and other organic acids, but no silicates or phosphates (except in the case of Toyota's pink extended-life coolant, which adds a dose of phosphate to its extended-life OAT-based antifreeze). Organic inhibitors do not deplete as quickly as the inorganic inhibitors used in conventional coolants.
•Hybrid OAT (HOAT) coolants, such as "Zerex G-05®" Use organic acids, but not 2-EHA (2-ethylhexanoic acid) (different organic acids are used). Hybrid OAT coolants add some silicate to provide quick-acting protection for aluminum surfaces. Silicate also helps repair surface erosion caused by cavitation in the water pump. Hybrid OAT coolants are currently used by many European vehicle manufacturers (BMW, Mercedes & Volvo) as well as Ford and Chrysler. Toyota adds some phosphate to their hybrid.