Working of thermosyphon cooling system in IC engine

Have you ever wonder about how the cooling system works in an IC engine? In this post, I’m going to explain the working of the thermosyphon cooling system in engines and its drawbacks. This is one type of water cooling system.

thermosyphon cooling system working
Diagram of the thermosyphon cooling system

Working of thermosyphon cooling system:

  1. This cooling system has different parts such as the radiator, fan, lower tank, upper tank, lower hose pipe connection, upper hose pipe connection, and cylinder water jacket as shown in the thermosyphon cooling system diagram.
  2. The thermosyphon cooling system is so designed that the water may circulate naturally because of the density difference between hot water and cold water.
  3. This system has a radiator and its upper and lower tanks are connected to upper and lower water jackets of the cylinder using the pipes.
  4. The hot water in the jacket rises and flows into the upper tank due to lower density compared to cold water and cold water from the radiator flow to the lower water jacket to replace the present hot water.
  5. Hot water from the upper tank now flows towards the lower tanks. The fan fitted across the tubes which are driven by an engine crankshaft cool down the water and collect it at the lower tank.
  6. To increase the rate of heat transfer, the surface area of the radiator is exposed to the air blast is covered with fins.
  7. The thermosyphon cooling system in automobiles and transformers uses the same principle of cooling.
  8. This cooling system is suitable for only low capacity engines
  9. For extra knowledge, this system is also used in CPU cooling.

See More What is carburetor? Explain types of carburetors

Disadvantages of thermosyphon cooling system:



  • In this system, the radiator needs to be kept above the engine cylinder level for the flow of water to the engine under gravity for the efficient functioning of the system.
  • The circulation of hot water is started only when engines become hot.
  • The thermosyphon cooling system is not suitable for heavy-duty engines where a very high rate of heat transfer is required.
  • The level of water in the radiator should be kept above delivery pipes to avoid an excessive temperature rise of cooling water and the formation of steam.
  • In this system, the temperature of the cooling water should strictly maintain. It should not be allowed to increase by more than 80ºC.

Mechanical Engineering Project Ideas for College Students

To understand this concept in deep, you should watch the thermosyphon cooling system animation on youtube.

Our downloads:

Need this article offline?

Download thermosyphon cooling system ppt and pdf

1 thought on “Working of thermosyphon cooling system in IC engine”

Comments are closed.