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Types of Cooling System In Engine – Working and Advantages

In this article, we discuss the types of cooling systems In the Engine.

What is an Engine Cooling System?

All the I.C. engines require a cooling system because the combustion of fuel takes place inside the engine itself.

All the heat produced by fuel combustion in the engine cylinders is not converted into useful power at the crankshaft. Only about 30% of the heat is converted into mechanical work. About 40% goes off through the exhaust. The remaining 30% is useless to waste heat.

It is seen that the quantity of heat given to the cylinder walls is considerable. If this heat is not removed from the cylinders, it would result in the seizing of the piston, high fuel consumption, pre-ignition, and burning of lubricant, etc.

Considering the above facts, it is observed that suitable means must be provided to dissipate excess heat from the cylinder walls to maintain the temperature below certain limits.

Therefore the method of removing away the excess heat from the engine cylinder is called a cooling system.

Read Also: How Does A Fuel Injection Pump Works?

Components of Cooling System in IC Engine

The following are the main components that are present in the IC engine:

#1 Radiator

A radiator is a component of the engine’s cooling system that spreads a mixture of antifreeze and water, releasing heat while absorbing cool air and returning it to the engine.

#2 Fan

The radiator fan (or fans) circulates cooling air through the car’s radiators. Cooling fans are positioned between the radiator and the engine.

These are useful when the car is stopped or traveling at a slow enough pace to prevent air from passing through the grille.

#3 Reserve Tank

A coolant tank controls the amount of extra coolant that your engine produces as a result of heat.

#4 Pressure Cap

The cap controls the maximum pressure, protecting the pipes and radiator. The coolant undergoes significant contraction as the system cools down after the engine stops.

#5 Water Pump

Through the water pump, coolant is pumped through the radiator, into the engine, and back again.

#6 Thermostat

A thermostat’s principal function is to keep the car’s engine running at a minimum temperature.

#7 Heater Core

The car’s heater is the heater core. It is responsible for raising the temperature within the car’s passenger compartment, or cabin.

It performs this by forcing hot air produced by the cooling system and engine into the car’s interior.

#8 Hoses

Hoses transmit antifreeze, or permanent coolant, throughout the engine, heater, and radiator.

#9 Bypass System

This technology lets coolant skip the radiator and return straight to the engine, which helps to maintain an appropriate coolant temperature.

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Types of Cooling Systems in Engine

The following are the two types of cooling systems for engines:

  1. Air cooling system
  2. Water cooling system

Air Cooling System

An air-cooled system is generally used in small engines say up to 15-20 kW. The air system is used in the engines of motorcycles, scooters, airplanes, and other stationary installations. This system is also used in car engines in countries with cold climates.

Air cooling system

The heat is dissipated directly to the atmospheric air by conduction through the cylinder walls. To increase, the rate of cooling, the outer surface area of the cylinder and cylinder head is increased by providing radiating sins and flanges. In bigger units, fans are provided to circulate the air around the cylinder walls and cylinder head.

Advantages of Air Cooled System

The following are the advantages of the air-cooled system:

  • The air-cooled system has no radiator or pump so the system is light.
  • In the case of a water cooling system, there are leakages, but in this case, there are no leakages.
  • Coolant and antifreeze solutions are not required.
  • This system can be used in cold climates, where if water is used it may freeze.

Disadvantages of Air Cooled System

  • Comparatively, it is less efficient.
  • It is used in airplanes and motorcycle engines where the engines are exposed to air directly.

Water Cooling System

The water cooling system is used in the engines of cars, buses, trucks, etc. In this system, the water is circulated through water jackets around each of the combustion chambers, cylinder, valve seats, and valve stems.

The water is kept continuously in motion by a centrifugal water pump which is driven by a V-belt from the pulley on the engine crankshaft. After passing through the engine jackets in the block and cylinder heads.

The water is passing through the radiator. In the radiator, the water is cooled by air drawn through the radiator by a fan. Usually, the fan and water pump are mounted and driven on a common shaft.

After passing through the radiator, the water is drained and delivered to the water pump through a cylinder inlet passage. The water again circulated through the engine jackets.

Types of Water Cooling System

A water cooling system has the following types:

  1. Thermosyphon cooling system.
  2. Impeller circulation system.
  3. Pump circulation system.
  4. Pressurized cooling system.
#1 Thermosyphon Cooling System

In this system, the natural convection of water is used. i.e. hot water has a lower density and rises. The hot water in the water jacket rises, in this way, and goes radiator top, from where it passes down and is cooled, and is collected in the bottom tank.

From the bottom tank again it goes to the water jacket of the cylinder block. This natural circulation system is used in very old model cars.

#2 Impeller System

This is an improvement over the thermosyphon cooling system. It is similar in all respects except that it has a small impeller unit driven by the engine itself to increase the circulation rate of water.

#3 Pump Circulation

This is the modern arrangement of water cooling in which the water is circulated effectively from the cylinder block to the radiator and back using a centrifugal pump driven by the engine v-belt.

4. Pressurized System

This is an improvement over the pump circulation system of cooling. In this system, there is a special radiator cap having a spring-loaded pressure valve and a vacuum valve.

The cap is gas-tight when the engine is heated, water vapor is formed and this is not allowed to go out. Therefore the boiling point of water in the system is raised, so that the working temperature of the engine also rises. A higher temperature gives better thermal efficiency.

The pressure valve opens when the pressure in the system exceeds a certain predetermined valve, say 0.5 kg cm². This allows the steam to escape, thereby avoiding excessive pressure formation. When the engine is cooled the vacuum valve opens and compensates for the loss of water or air.

Advantages of Water Cooling System

  • Uniform cooling of the cylinder, cylinder head, and valves.
  • Specific fuel consumption of the engine improves by using a water cooling system.
  • If we employ a water cooling system, the engine need not be provided at the front end of the moving vehicle.
  • The engine is less noisy as compared with air-cooled engines, as it has water for damping noise.

Disadvantages of Water Cooling System

  • It depends upon the supply of water.
  • The water pump which circulates water absorbs considerable power.
  • If the water cooling system fails then it will result in severe damage to the engine.
  • The water cooling system is costlier as it has several parts. Also, it requires more maintenance for its parts.

Read also: Basic Engine Components (Engine parts Names and Pictures)

Difference Between Air Cooling System and Water Cooling System

Cooling system for ic engine [Comparison between air cooled and water cooled systems in ic engine]

In [Cooling system for IC engine] The following point is important for the comparison of air cooling and water cooling systems.

Pros and Cons of Air Cooling System

  1. The design of this system is simple and less costly.
  2. The weight of the cooling system (per b.h.p. of the engine) is much less.
  3. The fuel consumption (per b.h.p. of the engine) is more.
  4. Its installation and maintenance are effortless and less costly.
  5. There is no danger of leakage or freezing of the coolant.
  6. It works smoothly and continuously. Moreover, it does not depend on any coolant.

Pros and Cons of Water Cooling System

  1. The design of this system is complicated and more costly.
  2. The weight of the cooling system (per b.h.p. the engine) is much more.
  3. The fuel consumption (per b.h.p. the engine) is less.
  4. Its installation and main tenace is difficult and more costly.
  5. There is a danger of leakage or freezing of the coolant.
  6. If the system fails, it may cause serious damage to the engine within a short time.


That is it, Thanks for reading. Now, I hope that you have learned about the “different types of cooling systems“. If you have any questions or doubts about this article, you can ask in the comments. If you liked this article, then please share it with your friends.

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Read More:


What is the cooling system in an engine?

The purpose of a car’s cooling system is to maintain a comfortable temperature and prevent internal combustion from overheating the engine.

What benefits does the cooling system of an IC engine offer?

An IC engine’s cooling system has the benefits of reducing overheating, boosting performance, and lengthening engine life.

What are the two basic types of cooling systems?

Cooling systems can be broadly classified into two types: air-cooled systems and water-cooled systems.

What type of cooling system is better?

In some applications, engine size, and design requirements will dictate which cooling system should be used. Air and water cooling systems are both used in different types of engines.

About Saif M

Saif M. is a Mechanical Engineer by profession. He completed his engineering studies in 2014 and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at www.theengineerspost.com

44 thoughts on “Types of Cooling System In Engine – Working and Advantages”

      • I really loved the article 😀and it is too simple and crisp enough information was provided.. Please continue writing these type which are so helpful than reading complex text books… Thank you one again 💓


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