In the past, amines were also used, but these have since become unfavourable due to the formation of carcinogenic nitrosamines. Such types of compounds include a variety of elements: silicates, nitrites, nitrates, molybdates, phosphates and borates. They are typically readily available and relatively cost-effective. These compounds are therefore very effective at producing a barrier against corrosion. These compounds are soluble inorganic molecules, which react (passivate) with the metal surfaces to produce an impervious physical layer that prevents any further corrosion reactions from taking place. IAT contains either EG or PG, and is usually fortified with silicate or phosphate additives to make it compatible with metal cooling system components.Ĭonventional inorganic (traditional) inhibitors have been known in the marketplace for over 60 years, and were first known to exhibit corrosion prevention features early in the previous century. Inorganic acid technology (IAT) is the chemical basis for the traditional green antifreeze. Generally, coolant corrosion inhibitors can be categorized into three distinct types:ġ. Conventional inorganic corrosion inhibitor compounds (traditional coolants).Ģ. Extended-life organic-acid inhibitor compounds (OAT coolants).ģ. Combinations of OAT and traditional inhibitors (hybrid or HOAT coolants). Each of these metal surfaces, and coolant design systems, present different corrosion inhibition problems that are addressed by different inhibitor compounds. Many modern engines use a variety of metals – from lightweight aluminum and aluminum alloys through to heavy-duty mild steel and heavier alloys. Many of these are selected specifically for the purpose of inhibition of certain types of metal surfaces found in engine systems.
There are very many different types of corrosion inhibitor compounds in the market that are used in the formulation of engine coolants. Coolants must also contain additives that inhibit corrosion and scale formation in the engine and radiator. As an example, there are at least three different shades of green coolant from three different manufacturers, none are the same formula,” explains Prestone technical training director Jay Buckley.Įngine coolants perform several functions in addition to providing freeze and boil protection. It doesn’t even signify what manufacturer the coolant was OE on. “Coolants in automotive light-duty applications are dyed many different colours the colour of any automaker’s particular coolant does not tell the technician what the formula is. The easy part is that most antifreeze manufacturers still make coolant with ethylene glycol (EG), while some use less-toxic propylene glycol (PG).
Today, with different types of antifreeze technology in a rainbow of colours, confusion abounds among automotive people and consumers alike as to what colour antifreeze is best.
Perhaps a RAV4 owner who is a chemist could determine whether this is a correct or incorrect assumption.Not all that long ago, no matter which brand of antifreeze you chose, it was green. This technology provides superior protection to all components of the cooling system including those exotic materials like aluminum and magnesium found in the modern day engine."Īccording to the article Toyota coolant and Chevron Dex-Cool would appear to be based upon the same technology. OATs are Long Life Coolants (LLC), based on minimally depleting Carboxylate Technology. "OAT is an acronym for Organic Acid (Additive) Technology which describes the type of materials responsible for the corrosion protection offered by a coolant of this type. From an article by Reochem, Inc., Coolant Experts:
TOYOTA SUPER LONG LIFE COOLANT ALTERNATIVE MANUAL
The Toyota RAV4 Owner's Manual says that coolant used should be either Toyota Super Long Life Coolant, or "Similar high quality ethylene glycol-based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life hybrid organic acid technology." Chevron Dex-Cool coolant employs the same labeling and uses the word "carboxylate" in its technical data description, rather than "organic acid," which Toyota uses. Rich - What is the problem with Dexcool? I use Chevron Dexcool in my motorcycle and according to the label specs it meets all of Kawasaki's requirements as in the owner's manual and also Toyota's as printed in that owner's manual.įrom an analysis which I did for another thread:
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