Antifreeze & Additives

Coolant is a mixture of water and antifreeze. Antifreeze lowers the freezing point of the mixture and raises the boiling point, and it contains additives that prevent corrosion, and lubricate pump seals. Ethylene glycol is the main ingredient of antifreeze, with the additives making up 10% or less of the total. A 50/50 mixture is generally recommended, and this provides freezing protection down to -34°F (-36.7°C) and boiling protection up to 265°F (129°C).

Although they are just a small percentage of the liquid, it is the additives that differentiate between the different types of antifreeze. IAT (Inorganic Acid Technology) is the traditional green antifreeze, and has silicate or phosphate additives for protection. However, these additives deplete quickly, requiring this type of coolant to be replaced frequently. OAT (Organic Acid Technology) antifreeze uses additives mostly comprised of organic acids, while HOAT (Hybrid Organic Acid Technology) has both organic and inorganic additives. OAT and HOAT antifreeze are considered long-life coolants and are the type specified for most modern vehicles. The types of coolant should not be mixed, as the additives in one may not be compatible with the other. For optimal protection, always use the type of antifreeze specified by the vehicle manufacturer.

Even long life coolants eventually wear down and are not able to provide freezing and boil over protection, and the additives become depleted. Most vehicle manufacturers have a recommended coolant replacement interval. When replacing the coolant, it’s a good idea to flush the cooling system, especially if there is evidence of scale and mineral buildup. A radiator flush product should be used as it will remove more rust, scale and sediment than plain water alone. Follow the directions on the flush container label, which may entail draining and filling the system several times. Always properly dispose of used coolant and wipe up any spills. Ingesting ethylene glycol can be fatal and children and animals are attracted to its sweet smell. Coolant also picks up metal particles like iron, aluminum, brass, copper, and lead, as it circulates through the cooling system, which classifies it as a hazardous waste.

High performance engines that make lots of horsepower also tend to generate a lot of heat, and it’s not uncommon for vehicles with these engines to run hotter than their owners would like. Excessive heat can cause expensive engine damage, but the cure for the problem can be as simple as including a coolant additive when filling your system. These additives contain agents that reduce air bubbles and air pockets so there is complete coolant contact with all internal surfaces. This increases the coolant’s heat transfer abilities resulting in a cooler running engine. These additives also include rust and corrosion inhibitors to prevent buildup that can reduce cooling system efficiency.