Coolants play an important role in our past and our future. From the design of your vehicle’s engine to the way it functions, all aspects are dictated by the optimization and protection offered by coolants. This inconspicuous substance allows vehicles to travel faster and to transport more, effectively changing the course of history. The origins of coolants are rooted in simplicity, but as we look to the future, a complex story begins to unfold, particularly as we look to electric vehicle coolants and fuel cell vehicle coolants.
The internal combustion engine (ICE) came onto the scene in 1876. These engines, still in use today, work exactly as the name suggests. Tiny sparks of combustion within the engine convert to energy, allowing your vehicle to move. This produces an immense amount of heat which, if uncontrolled, will destroy the engine. Upon its invention, it became immediately apparent that there was a need for some sort of liquid or gas that would effectively and safely transfer and absorb this heat. The first coolant was pure water.
Water does, indeed, manage and transfer heat incredibly well. It has its downsides as well. Water alone freezes at 32° F (0°C) and boils at 212° F (110° C). Outside of this range, water loses its functionality. At its boiling point, heat is transformed into steam and when frozen, it expands as ice. Both forms present a list of issues and can not transfer heat effectively. To do the job properly, something needed to be added to the water.
Ethylene glycol (EG) is one of the earliest antifreezes. It was initially synthesized in 1856 and was later used in the production of explosives. With its boiling point at 386°F (197°C) and a freezing point at 10°F (-13°C), EG allows for a much wider range of functionality. The chemical on its own, however, does not conduct heat as efficiently as water. By combining equal parts water and EG, the functional range of the coolant was expanded to -34°F to 265°F while retaining the efficient heat transfer offered by water.
Later, propylene glycol (PG) also became available. This glycol is less toxic than its counterpart but lacks the heat transfer ability that EG provides. Versatile PG and hearty EG truly changed the game as engine designs evolved and their utility widened. Between these two chemicals, manufacturers have been able to customize coolants for various uses.
As time went on, it soon became apparent that coolants had one more issue to address. When liquid is introduced to metal, such as when a coolant is introduced to an engine’s cooling system, the metal begins to corrode over time. Corrosion in your vehicle’s cooling system spells disaster for any engine. To combat this damage, corrosion inhibitors were introduced to the water and EG mixture. Corrosion inhibitors ensure that the liquid coolant is alkaline. Over time, acidity does begin to increase, however. Coolant must be changed before this happens or corrosion will begin unchecked.
In order to extend the life of your coolant, industry leaders began to develop Organic Acid Technology (OAT) coolants in the late 1980s. Using some variation and mixture of borate, nitrate, phosphate, or silicate as additives to coolants, they were able to create a coolant that needed to be changed closer to 150,000 miles of usage rather than the standard 30,000 miles offered by conventional coolants. Though longer-lasting, corrosion protection may be less effective in these coolants than their shorter-lasting counterparts.
Hybrid organic technology (HOAT) coolants have also become popular. A hybrid of OAT and inorganic acid technology (IAT), it is often touted as the best of both worlds. When professionally mixed and curated, it truly can change the way you approach your vehicle’s cooling system. For now, it is the latest and greatest but we know that it is just a stepping stone for a coolant that will change the game once again.
From a simple mixture of water and glycol to the building block of innovation, coolants have come a long way. We are reaching for a future where coolants keep in step with advances in automotive technology and with each step, the opportunity for greatness becomes clearer.
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Davis, A. (2020, November 29). What Is The Difference Between HOAT Coolant and OAT Coolant? MotorCare Guys. https://motorcareguys.com/what-is-the-difference-between-hoat-coolant-and-oat-coolant/.
Encyclopædia Britannica, inc. (n.d.). Antifreeze. Encyclopædia Britannica. https://www.britannica.com/science/antifreeze-chemical-substance.
A History of Automotive Coolants. Know Your Parts. (2017, March 20). https://www.knowyourparts.com/technical-resources/engine/a-history-of-automotive-coolants/.