Quote:
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Originally Posted by wanna986
MN,
The other day I came across a "universal" coolant which claims to be compatible with everything out there.
If the claim is true, it would be a good thing for me who has to deal with everything from a 1973 to a 2002.
Your take on this?
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Hi,
It may well be
compatible, but that's no recommendation to mix it with other types. There are basically two types of Coolant out there (there are more, but the differences aren't really relevant for this discussion). Both are usually Glycol based (either Propylene Glycol, or Ethylene Glycol).
In addition to the base fluid, there are a small amount of other ingredients including corrosion inhibitors, antifoaming agents, dyes and other additives. While these other ingredients make up only a small fraction of the overall coolant, they are what differentiate one coolant from another.
Conventional Coolants typically use a Phosphate/ Silicate mix as the main components in their Inhibitor pkg. Conventional inhibitors like Silicates and Phosphates work by forming a protective layer that actually insulates the metals in the engine and Radiator from the Coolant. These inhibitors can be characterized chemically as
Inorganic Oxides (silicates, phosphates, borates, etc.). Because these Inhibitor Pkgs. are depleted by forming this protective layer, conventional Coolants need to be changed at regular intervals, usually every two years.
But, in Europe, with unusually hard water (compared to the US), minerals forced Coolants to be Phosphate-free. Calcium and Magnesium, minerals found in hard water, will react with Phosphate Inhibitors to form Calcium or Magnesium Phosphate, this can cause the formation of scale on hot engine surfaces. This results in a loss of heat transfer and/or corrosion under the layer of scale.
Instead of Phosphates, conventional European coolants contain a mix of Inorganic Oxides like Silicates and Inhibitors called Carboxylates. Carboxylates differ in their corrosion protection in that they chemically interact with the metal at corrosion sites in the engine, instead of forming a layer of Inhibitors that cover the total surface.
In Asia, where the water is OK, Silicates are the problem. Issues with water pump seals, heat transfer, toxicity and non-biodegradability led to a ban of coolants containing Silicate. To provide protection, most coolants contain a mix of Carboxylates and Inorganic Inhibitors like Phosphates.
Extended-Life Coolants are usually Carboxylate-based and were developed to be globally acceptable and provide superior performance over existing chemistry. This chemistry is also known as Organic Additive Technology (OATs). Because full Carboxylate coolants have no Silicates, they meet the stringent requirements of the Asian specifications, but they also meet the European coolant requirements because they have no phosphates. These coolants have developed international popularity due to having an unsurpassed corrosion protection for extended time intervals. They have the added benefit of working better, being non-toxic and are biodegradable.
In these Coolants (which is what Porsche uses) the corrosion protection is provided by Carboxylates. Carboxylate Inhibitors provide corrosion protection by chemically interacting with the metal surfaces where needed, not by laying down insulating layers. This allows: extended life cycles, unsurpassed high temperature aluminum protection, as well as heat transfer advantages on both hot engine surfaces and radiator tubes where heat transfer is critical. But, it can still breakdown in usually a 5yr./150k mi. interval. Porsche calls it
Lifetime for Marketing purposes. They expect the average car will have it's cooling system opened or drained for Service sometime in it's Coolant's 5-year life span and have it's Coolant replaced then. Hope this helps...
Happy Motoring!... Jim'99