In recent years, antifreeze manufacturers have been creating universal coolants that are meant to work on all vehicle types. These extended-life coolants only differ in colour. Some may be orange while others may be dyed blue or purple. While universal coolants are meant to remove confusion, there are types made for specific vehicle makes.
Green antifreeze is the traditional type of antifreeze most commonly used in North America. The silicate and phosphate make-up of the product provides protection for aluminium and bare iron surfaces. It is important to use the correct type of coolant for your vehicle. For example, do not use an OAT coolant when the manufacturer specifies to use an hybrid OAT coolant. This coolant needs to be changed every 30,000 miles or once every two to three years.
OAT, short for Organic Acid Technology, are coolants containing ingredients such as 2-ethylhexanoic acid (2-EHA), sebacate and other various organic acids. Unlike green antifreeze, they generally do not contain silicates or phosphates. Usually, OAT-based coolants will be dyed a different colour than green antifreeze. This is to distinguish the two types. A vehicle utilising this coolant must change the antifreeze once every five years or 150,000 miles.
Hybrid OAT is also commonly known as G-05 or HOAT antifreeze. The formula for this antifreeze uses organic acids but not 2-EHA and usually include silicates to provide protection for aluminium surfaces. HOAT is used by many European car manufacturers, though they are also used by American companies such as Chrysler and Ford. A HOAT coolant will need to be changed every five years or 150,000 miles.
Universal coolants claim that they may be used with any vehicle type regardless of its year of production or manufacturer. The idea behind these types of antifreeze is to remove confusion that other types of coolants may cause the consumer. Universal coolants tend to use OAT-based corrosion packages with carboxylate and other organic acids added to provide a wide range of protection. If this type of coolant is added to a system utilising the OAT or hybrid coolant technology, it will need to be changed every five years or 150,000. However, if it is used in an older system that uses traditional green antifreeze, the change will need to be made every three years or 30,000 miles.