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Frequently Asked Questions

Some frequently asked questions about coolants, heat transfer fluids, use of antifreeze, etc.

If you cannot find the answer to your question in the FAQ section, please do not hesitate to contact us.

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What is the main function of a coolant?

The main function of a coolant is to transfer heat - primarily to remove the heat of the engine and to reduce the risk of overheating. A coolant also protects the engine against freezing and boiling and against corrosion, cavitation and erosion.

What is OAT?

OAT is the abbreviation for Organic Additive Technology. It was discovered a couple of years ago that certain organic compounds (organic acids) provide outstanding corrosion protection on many kinds of metals and alloys. Arteco was one of the first to commercialise OAT coolants in Europe. The Organic Additive Technology gives long lasting corrosion protection because the organic additives do not deplete even after many operating hours or high mileages. OAT Coolants, such as Havoline© XLC, are often referred to as Extended Life coolants or Long Life coolants.

What is silicate?

Silicate is a mineral that is found all over the world and is a major constituant of sand, many rocks and stones. Silicate has to be extracted from natural sources in an energy consuming process before it can be used as corrosion inhibitor in coolants or in other applications such as construction material, inorganic fillers for plastics, paints and coatings or raw material for photovoltaic applications.

Silicate is a mineral or inorganic corrosion inhibitor with a relatively fast action on aluminium and aluminium alloys. It works by a formation of closed thin layers on aluminium surfaces. The disadvantage of that mechanism can be, as with many other mineral corrosion inhibitors, the hindrance of the heat transfer from aluminium engine parts to the coolant. In order to have a long term corrosion protection and good heat transfer on aluminium and on other metals and alloys, the silicate is almost always combined with OAT technology.

As inorganic inhibitor, silicate tends to agglomerate under demanding operating conditions of vehicles (passenger cars, heavy duty, ...) which compromises the corrosion inhibition on aluminium and its stability in the coolant. These problems are addressed in Arteco's silicate OAT lobrid coolants.

What is flux?

Flux is a chemical, a so-called process aid, also known under the name nocoloc (Solvay trademark name). It is used in the welding process of aluminium heat exchangers. Flux prepares the aluminium surface for the welding process and reduces substantially the welding temperature. Flux remains as a flux residue in the inside of the finished aluminium heat exchanger.

What are the consequences of flux interacting with an engine coolant?

As Flux remains as a flux residue in the inside of the finished aluminium heat exchanger after the welding process, the remaining flux comes into contact with the coolant at the moment of the filling process of the cooling system.  Flux will interact with the corrosion inhibitors present in the coolant, and the interaction is different depending on the type of inhibitors.

Mainly inorganic corrosion inhibitors such as silicate have a high risk to interact with the remaining flux. The potential long term consequences are reduced availability of silicate for aluminium corrosion protection and the formation of gelish deposits. The deposits tend to block narrow ducts and/or channels in the cooling system particularly in heat exchangers.

This phenomenon is partially prevented by the heat exchanger manufacturers by extraction of flux residues from the aluminium heat exchangers which is a costly process. The better way to prevent this is to use Arteco's silicate-free OAT based or silicate stabilised coolants.

Do you have to dilute a glycol-based coolant?

Concentrated coolant can never be used in the application as such in view of heat transfer properties due to the high glycol concentration. In addition, compatibility with cooling system materials can be negatively affected.

In general a concentrated coolant is diluted in function of a targeted and/or required freeze point. Typical coolant concentrations do range between 40% and 50% and in some cases up to 60%;