Main Components of Coolant & How Car Coolant Works?

Main Components of Coolant & How Car Coolant Works?

Main Components of Coolant & How Car Coolant Works

To know how a car coolant works, you need to understand that a car engine emits lots of heat when operating. The engine works at extremely high temperatures and needs to cool down to avoid any damage. Here, enters the coolant whose main job is to regulate the constant temperature.  Coolant or antifreeze solution circulates in the cooling system and passes through special thin tubes.

Can you imagine what will happen if the engine gets overheated in summer or gets cold in winter?  it will produce more pollutants and the components will become less efficient. Overheating can explode cylinder head gaskets and can crack the engine blocks.

In case, the engine has stopped working and excess heat cannot be removed, then you might have to change the whole engine. As pistons are welded inside the cylinders. 

when you just must throw the engine away and buy a new one. So, you should take care of your engine cooling system and learn how it works.

The cooling system ensures the engine works properly and prevents any severe damage. Read this article to learn how an engine cooling system works, and its components.

Main Components of the Cooling System


The radiator is made of aluminum and consists of fins attached to small-diameter pipers. It comes with an inlet port, a sealed cover,  a drainage plug, and an outlet port. It works as a heat exchanger for the engine. It replaces the heat of hot water with the ambient air.

Water pump

Once the coolant has traveled in the radiator, the job of the water pump is to send the coolant back to the cylinder block, heater core, and cylinder head. That means, the antifreeze solution travels twice in the radiator after it gets cooled down.


A thermostat senses the temperature and works as a valve for the coolant. The fluid can enter the radiator only after the thermostat has been triggered. It regulates the standard operating temperature of the engine during the combustion process, The antifreeze solution can only pass through the thermostat after it has exceeded a specific temperature.

Freeze Plugs

These plugs are made using steel material. As the name suggested, it has been designed specifically to freeze the openings in the cylinder head and cylinder block. Keep in mind that special frost protection is also required if you are in a habitat of extremely cold regions. Otherwise, the fluid can pop out.

Timing head/cover gasket: Its function is to seal the primary parts of the engine. It protects antifreeze fluid, cylinder pressure, and oil from mixing together.

Radiator overflow tank: This tank is made up of plastic and comes with an overflow hole and an inlet. The radiator overflow tank is fitted next to the radiator. It’s the tank where you put water before driving.

Hoses: They are made up of rubber material. Hoses work as a connector that passes the fluid between the radiator and the engine. They usually start leaking when the engine starts becoming old.

How does the engine cooling system work?

First of all, you need to understand what the cooling system actually does. Can you guess? It’s pretty simple! The cooling system cools down the excess heat produced during the combustion process. 

But it’s not as easy as it seems to be. The bigger the engine, the more heat is produced in the system, and the more complex it is for the cooling system to remove the excess heat.   

For example, A small car traveling at 50 miles per hour can produce about 4,000 explosions in a minute.

If the cooling system is not efficient enough, the engine will stop operating within a few minutes and may explode in severe cases of overheating. 

Advanced cooling systems along with the engine-driven fans make sure to keep the temperature constant in both the summer and winter seasons. These fans are usually installed over cylinder casings and blow air consistently to operate the cooling system smoothly.

Some Basics You Need to Know:

  1. As fuel constantly burns in the car, a lot of heat is produced during the combustion process. Some of the heat goes into the exhaust while some of it is soaked in the engine. 
  2. The engine’s efficiency is increased when the coolant is 200 degrees Fahrenheit.
  3. At the right temperature, the engine provides better combustion & low emission.
  4. The oil used for lubrication has a low viscosity which means engine parts can move freely.

Understand the Cooling system (step-by-step Process)

  1. The coolant is consistently passed through the engine block via different channels.
  2. Then, the water pump carries the coolant and pushes it across the cylinder block. This antifreeze fluid absorbs the excess heat from the car engine.
  3. Now, this heated coolant enters the radiator and is cooled down by the air generated through the radiator grill. 
  4. While traveling again through the radiator it will absorb more heat.
  5. Now comes the role of the thermostat that is installed between the engine and radiator. It won’t let the fluid enter until the radiator reaches a certain temperature.
  6. In a situation, where the fluid temperature falls below the specs, the fluid will bypass the radiator and travel back to the engine block.
  7. The antifreeze solution keeps circulating until the radiator reaches the required temperature. As soon as it reaches the desired level, the thermostat is triggered and opens the valve to enter into the radiator.
  8. Under high engine temperature conditions, the fluid immediately reaches its boiling point. Whereas the cooling system prevents excess heating and pressure build-up. The excess pressure can damage the gasket or hose. 
  9. The radiator cap helps relieve the excess pressure generated by disposing of in the reserve tank.
  10. Once the fluid has cooled down, it is again re-circulated in the cooling system

Common Questions & Answers

What is Car Engine Coolant?

The main task of car coolant is to protect the car engines from overheating. They also lubricate other parts in motion when they come in contact. So, they protect the water pump, piston, and head gaskets from severe damage.

What is Antifreeze Coolant made of?

All automobile coolants contain glycol. A coolant is a mixture of distilled water, anti-corrosion, or other properties. It may contain ethylene glycol or propylene glycol based on the type of coolant. Propylene glycol is comparatively less toxic than ethylene.

How often should I Change the Coolant?

Although it depends on the type of coolant you have used in your vehicle, it is still recommended to flush and change the coolant every 30,000 miles. Many of the new models need coolant services every 10,000 miles.

What are the different cooling systems used in cars?

There are two types of cooling systems used in cars as liquid-cooled and air-cooled cooling systems.  Almost all new automobiles use liquid-cooled cooling systems.

What is the function of the water pump in a cooling system?

The water pump circulates the coolant in the cooling system, while the engine is running. The pump is connected next to the engine’s crankshaft.

Wrapping up!

So, now you have a clear idea about the different components of coolant and how it works. Not only does it prevents the engine from overheating but its additional properties also protect the metal parts of the engine from corrosion. Keep in mind to never use water instead of coolant in your car. It will only reduce the engine’s efficiency.

Do you need more information about coolants? Read our other detailed articles and find out which is the best coolant for your cars in India.