Coolant is a liquid that is used to decrease or control the temperature of a metal-working system. Its main goal is to prevent the engine from freezing during the winter and to keep it from overheating during the summer. Coolant does this by keeping the system from forming either a solid or a gas. It does this by collecting the heat from the engine, then it moves to the cylinder head to collect heat from there as well. The coolant then flows through the thermostat and is pushed through the radiator, where it is cooled by the air that flows through the radiator. By the time the coolant is cooled, it is returned back to the water pump to collect more heat and the process begins again. 

Coolant is a mixture of water, antifreeze, corrosion inhibitors, and lubricant. Other than preventing the engine from freezing or overheating, when using the correct mixture of these items it will also help to prevent rust and damage of metal parts, produce heat, and help prevent electrolysis (chemical breakdown). Water soluble coolant is a water and oil infused coolant. This type of coolant allows two or more liquids to mix together, when they are usually unable to be mixed together. It does this by allowing one fluid to break down the other fluid. It’s designed for use by light to heavy-duty working equipment and is either defined as soluble oils or semi-synthetic. Soluble oil is created by using hydrotreated base oils, a certain blend of inhibitors, debased additives, and a surface active agent. It also contains a substance that kills bacteria. Semi-synthetic coolant contains less than 30% of oil, lubricants, and different other types of additives. When water is mixed with this coolant, the fluid turns clear. 

There are three main types of coolants manufacturers use which are Inorganic Additive Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT). Inorganic Additive Technology coolant is the most commonly used coolant and is usually green in color. It contains silicate, which helps absorb and contain water vapor. IAT has a 5 year service life or 30,000 mile mark, meaning coolant needs to be replaced after 5 years or once the 30,000 mile mark has been met. IAT requires more maintenance, due to its service life span. Organic Acid Technology is usually orange in color and contains organic acids, which helps with corrosion and are less reactive with metals. OAT has a 5 year service life or a 150,000 mile mark, so it has a longer service life span. Hybrid organic Acid Technology is a mixture if IAT and OAT. It’s color is usually yellow, and contains silicate and organic acid. Just like OAT, it has a 5 year service life and a 150,000 mile mark, before replacement is needed. Now, that we understand what coolant is, how it works, and the different types of commonly used coolants.