Difference Between Antifreeze And Coolant: Which One Should You Use

The literal difference between the two is evident from their names i.e. the antifreeze is a substance that does not freeze easily and lowers the freezing point and coolant is something that brings down the temperature and prevents overheating. That is a simple gist of things. There is a bit more detail to it.


Antifreeze is a chemical that resists both high and low temperatures. It is most commonly a concentrate of MEG i.e. mono ethylene glycol or a less common and less toxic option MPG i.e. mono propylene glycol. An antifreeze’s main characteristic is that it freezes at extremely low temperatures and boils at ultra-high temperatures, and in this way regulates the temperature of the engine.

Since antifreeze is a concentrated liquid, it needs to be diluted with distilled water before use. This water laced antifreeze is what we call coolant.


Coolant is a mixture of antifreeze and distilled water. You can either buy it in a mixture form or separately and then mix it in any ration according to your engine’s specifications. Therefore, antifreeze and coolant both fulfil the same purpose. Coolant is the usable form of antifreeze. 

The most common variant of coolant is 50-50 ratio of antifreeze and water. There is also a 70-30 variant as well, with 70% antifreeze and 30% water. You should use the variant, which best suits your climate and manufacturer’s guidelines. 

However, there are other fluids that can be used as coolants that do not have antifreeze in them e.g. water, air, liquid sodium, oil etc.

Are They The Same?

Essentially, yes, they are the same. At least, when mentioning them in reference to the cooling system of engines, they are considered the same. Most people and even manufacturers are using both terms interchangeably. Nevertheless, the thing to remember is that for antifreeze to be usable, it must be diluted with water i.e. it must essentially become a coolant to be of any use. However, coolant is not just antifreeze + water. It contains other additives as well, like lubricants, corrosion inhibitors etc. The ratio, in which the antifreeze and water are to be mixed, depends on the climate and so higher concentration of antifreeze is used in colder regions.

Importance Of Coolant/Antifreeze:

A car’s engine must be at a balanced temperature all year round. This optimum temperature is essential for a problem free operation of the engine. This function is performed by the cooling system of the car. The cooling system performs this function with the help of coolant/antifreeze. 

The purpose of coolants/antifreeze is to regulate the temperature of fluids and various parts of the engine in all types of weather. The engine should be neither too hot nor too cold. Therefore, the engine needs coolant 365 days a year. A quality coolant not only cools the engine in high temperatures but it also prevents the cooling liquid from freezing within your radiator in extreme subzero weather by lowering its freezing point (due to its antifreeze property).  With this type of high quality coolant/antifreeze, you do not need to change or top up your regulator fluid with antifreeze or additives, every season. 

This product not only protects the engine and radiator fluid from freezing and overheating, it serves a secondary function of lubricating key engine parts that it comes in contact with, e.g. the water pump. This way it protects those parts from corrosion and rust. 

A little known purpose of coolant is that it keeps the car’s passenger compartment warm in winter.

How Does Coolant/Antifreeze Work?

The coolant flows throughout the engine via many small tubes and large hoses to not only keep the engine cool but also keep the heat balanced. This way while the engine is running, the coolant system keeps it from getting too hot or too cold.

Nowadays due to raising pollution levels, the auto industry has installed many systems and devices to keep the emissions in check and in this way minimize pollution. Now these devices work perfectly when the engine is working at its optimum operating temperature. This is again, where the coolant system comes into play. It gets the engine to that optimum temperature, when you start it, as quickly as possible. This is especially of great importance in winters when you start your car in the morning after it being in the cold all night. This coolant system is also responsible for providing heat inside the car in winters.

What Color Is Coolant/Antifreeze?

Antifreeze in its pure form usually comes in two different colors: green and orange. The orange antifreeze has an extended life than the green one due to different additives.

Whereas the ready-to-use coolant is available in green, purple/pink and orange colors. However, you must consult your manufacturer’s guidelines and buy accordingly, because the wrong variant can cause serious mechanical problems in your car.

Replacing Coolant/Antifreeze:

As all good things, the coolant/antifreeze does expire after some time. It gets contaminated with the rust, corrosion and gunk in the passageways it travels through. Generally, you need to replace it after every three to five years or you can change it earlier if the car is older or is on the road a lot. The old coolant must be completely flushed out and replaced with fresh supply. Whatever the case may be, it must be done in line with the manufacturer’s instructions. 

Summing Up:

As a good quality motor oil is of critical importance to the engine, it is the case of coolant/antifreeze. Both these fluids are responsible for the engine’s reliability and smooth performance. So make sure to regularly check the quantity and condition of your coolant fluids. Cars need some lovin’ too.

As Alexandra Paul once said:

The Cars We Drive Say A Lot About Us.

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