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Vehicle Fluids Part III: Coolant

Internal combustion engines, such as the one in your vehicle, necessitates the removal of excess heat. Therefore, the engine has a cooling system that requires coolant, which is a heat transfer fluid. Coolant also prevents freezing and protection from corrosion. When your engine is operating it can convert only about one third of the energy originating from the combustion of fuel into assisting to move the vehicle. Two thirds of this is converted into heat while another one third is released through the exhaust, which leaves the rest of this energy within the engine block. The engine block is then in need of coolant to absorb this heat and as the coolant absorbs the heat it then transports it through the radiator and sends it to dissipate into the environment. Due to this process, the engine is able to be fully efficient and operational.

Coolant is sometimes known as anti-freeze and vice versa. Both are really just generic terms used to describe a fluid that can remove heat from the engine to keep the engine from over-heating. Coolant can be just plain water and it can be effective for cooling the engine. However, it would not protect against freezing temperatures. Anti-freeze will not only restrict freezing points, but in addition to this, it will protect against corrosion and increases boiling point during use.

Anti-freeze is a mixture of glycol, which gives it the ability to suppress the freezing point and raise the boiling point, corrosion inhibiting compounds and dyes. There are two main types of glycol, ethylene glycol and propylen glycol The dyes are to help more easily identify it, therefore avoiding confusion as there are several different coolants available on the market today. There is usually a 1 to 1 mixture of water and glycol that results in a freezing point ranging from -37 Celsius to -42 Celsius, but this is all dependent upon the formula of the antifreeze.

There seems to be two basic types of coolant available on the market today that are dependent on corrosion inhibitors. The first is referred to IAT or inorganic additive technology. It is the most traditional that is made with inorganic additives, hence inorganic technology. This coolant is most dependable that provides a fast acting film to protect the vehicle. However, the additives eventually will deplete. When this occurs the coolant will need to be drained and replenished every couple of years. IAT coolant can be used on metal engines with components that include steel, aluminum, copper etc. without worry of causing damage.

The second coolant is referred to OAT or Organic Acid Technology. OAT coolants do work differently than IAT based coolants. In the event of moisture, aluminum and other metals that consist of iron, will begin to create a surface-layer corrosion. OAT coolants will prevent the metal layer against corrosion. This type of coolant is designed to last longer than traditional coolants, but is not to be used with engine systems that contain yellow metals.

To the contrary, the fluid must also have the ability to stay heated, but not reach boiling temperatures and avoid the creation of vapor because the vapor with diminish its' ability to transfer heat.


It is best to stick with what the vehicle manufacturer suggests. Most of the more modern engines require the long life organic antifreeze. Always be aware of what antifreeze is in your vehicle because you do not want to mix IAT with OAT antifreeze. The type of coolant fluid used also really depends on the type of material that forms the engine, the geography and the climate. So for instance, when you're vehicle is going to be exposed to seasons where there is extremely cold weather, the fluid must be able to withstand the freezing weather and not freeze. Specifically why it is referred to as "antifreeze" because it will provide protection against freezing. But, in other climates such as a more tropical environment, one will need coolant, but not necessarily need protection against freezing temperatures.


Okay, so the takeaways are as follows:

Always remember that coolant is very important to the engine in keeping it from over heating. Coolant assists with effective heat transfer. It prevents the cooling system from corrosion. It allows for an effective boiling point. It assists in avoiding freeze points and it allows for chemical stability in the engine.

But, most of all, always **REMEMBER**, Shige's Premier Auto Service is here for you! Any questions you may have, please, call us, write to us below, go to our website or visit us on Facebook!

Make a reservation and come down to the shop! We will make sure that your cooling system is working correctly so that your engine can run as efficiently as possible so you can be on your way to LIVING THE LEGACY!!