Engine Cooling System: Structure, Principles and Failures

The cooling system is one of the most important parts of a car. It plays a role in maintaining a stable operating temperature of the engine, preventing overheating and ensuring optimal performance.

Every engine generates a significant amount of heat when operating. In particular, for internal combustion engines, the process of converting thermal energy into mechanical energy at the crankshaft creates high temperatures. If not controlled, this temperature can cause serious damage to internal engine components such as pistons, piston rings, connecting rods, valves and cylinders. Therefore, equipping a cooling system is extremely necessary to ensure stable and efficient engine operation.

Working Principle

Engine cooling system can be divided into two types: liquid cooling system and air cooling system. Air-cooled systems can be found on today's digital motorcycles. The water-cooled cooling system is mainly used in cars due to its effective cooling capacity in most highway or city conditions, which often turn off the road.

The cooling system consists of cooling water circuits inside the body and the chip cover, the cooling water circuit goes around the body and chip cover to achieve the best cooling effect. A water pump is used to make the cooling water circulation, constant temperature valve used to adjust the cooling water temperature to the required temperature, a cooling water tank to cool the cooling water and a water tank cover to adjust pressure inside the cooling water pipe.

The cooling system works by transporting circulating cooling water around the body and the chip cover. As coolant circulates through them, it removes heat from the engine. Hot water will then be pushed to the cooling tank, the water will be divided into small pipes inside the tank and cooled by the wind generated by the cooling fan simultaneously with the wind generated by the car. to cool the water. When the hot water is cooled, it will continue to circulate back into the engine to continue the continuous cycle thanks to the operation of the water pump.

Thermostat valves are located between the engine and the water tank to ensure that the coolant is always kept at a certain working temperature. If the coolant is too ventricular, the thermostatic valve will close to prevent coolant from flowing into the radiator, the purpose of which is to quickly raise the temperature to the operating temperature. When the water temperature reaches the stable working temperature, the constant temperature valve will open to perform water circulation to the radiator.

To prevent the cooling water from boiling, the cooling system is designed to withstand pressure. When the pressure is higher, the boiling temperature of the water will increase, but if the pressure is too high, it will cause the body to crack or the water pipes to burst. Therefore, the pressure in the cooling system will be appropriately controlled by the radiator cap. When the pressure inside the cooling system is too high, the radiator cap will open to allow water to enter the auxiliary water tank, reducing the water pressure. When the cooling water temperature drops, the water in the auxiliary water tank will be drawn back into the system. This cooling system is called a closed circulating cooling system.

You can learn more about the principles of operation of the internal combustion engine cooling system through the video below:

Structure of cooling system

The car engine cooling system includes the following main components:

• Radiator: The main part that helps dissipate heat for the coolant. Radiators are usually made of aluminum with small pipes to optimize heat dissipation.
• Water pump: Has the task of circulating coolant through engine parts and radiator.
• Thermostat: Regulates coolant flow to maintain stable engine temperature.
• Fan: Enhances the radiator's cooling capacity by blowing air into the hot water pipes.
• Auxiliary water tank: Contains excess coolant and compensates when water in the system is lost.
• Pipes: Connect components in the system to ensure that coolant can circulate continuously.

Principle of operation

The cooling system operates on the principle of a closed circuit. When the engine starts, the water pump draws water from the radiator and pumps it into the channels around the combustion chamber to absorb heat. The hot water then returns to the radiator, where it is cooled by the circulation of air from the fan and natural wind when the vehicle is moving.

When the water temperature reaches a certain threshold, the thermostat will open to allow hot water to flow into the tank to dissipate heat. If the pressure in the system exceeds the allowable level, the tank cover will open to reduce the pressure, ensuring the safety of the entire system.

Coolant and its role

Coolant not only has the function of reducing temperature but also plays an important role in protecting metal parts from corrosion. The commonly used solution is Ethylene Glycol, which has the ability to resist freezing at low temperatures and does not cause corrosion to internal engine parts.

Important characteristics of coolant:

• Effective cooling: Coolant helps reduce engine temperature by absorbing and dissipating heat into the environment.
• Anti-freeze: Additives in the solution that help prevent freezing at low temperatures.
• Engine protection: Reduces friction between metal parts, prolongs engine life and reduces maintenance costs.

The damage of cooling system

Common failures in cooling systems

• Cooling systems can experience some serious problems if not properly maintained. Here are some common failures:
• Radiator leak or rust: If you see strange colors or dirt in the coolant, you should check the radiator immediately because this could be a sign of rust.
• Clogged radiator: Accumulated debris can clog pipes and prevent efficient cooling. Flush and clear the radiator to ensure free flow.
• Thermostat failure: If the valve does not open or close at the correct time, this can result in overheating or overheating of the engine.
• Faulty water pump: A failing water pump will cause the water flow to stagnate, leading to the risk of overheating the engine.
• Damaged cooling fan: A non-functioning fan will reduce the radiator's ability to dissipate heat. Check and replace if necessary.
• Leaking hoses: Rubber hoses can crack or break over time, causing loss of coolant.

Images of common cooling system failures:

Check and maintain cooling system

To ensure efficient cooling system operation:

• Regularly check the water level in the auxiliary tank before each trip.
• Monitor the temperature reading on the dashboard; if it exceeds 93°C, stop the vehicle immediately to avoid serious damage.
• Replace the coolant periodically (usually about every 2 years) to ensure optimal system performance.

Understanding the structure and operating principles of the cooling system will help users maintain high engine performance as well as prolong the life of the car.

FAQ – Frequently Asked Questions

1. What are the types of coolants and what are the differences between them?

Engine coolant There are two main types: Ethylene Glycol and Propylene Glycol. Ethylene Glycol has better antifreeze properties, but is toxic to animals if leaked. Propylene Glycol is safer for the environment and humans, but is often more expensive.

2. How to check the coolant level in the engine?

Users should check the coolant level in the sub-tank at least once a month. The water level should be between the maximum and minimum levels; if it is lower than the minimum level, the appropriate coolant should be added immediately. See the article now: 

3. How often should the coolant be changed?

Typically, coolant should be replaced every 2 years or after approximately 40,000 – 50,000 km of travel to ensure optimal performance and prevent corrosion.

4. What are the signs that the cooling system is having problems?

Signs include: engine temperature exceeding 93°C, coolant leaking under the vehicle, strange noises from the water pump or fan not working when the engine is hot.

5. How can the cooling system affect fuel efficiency?

If the engine temperature is unstable (too high or too low), this can lead to increased fuel consumption of 10% – 20% due to the fuel mixture not being adjusted correctly. See the article now: Cooling system testing method Fast, simple, and most effective, shared by many experts.

6. Where to replace/repair engine cooling system with good reputation and price?

At Thanh Phong Auto, we are proud to be one of the leading auto repair and maintenance centers in Ho Chi Minh City. Established in October 10, Thanh Phong Auto has gathered a team of experienced engineers and technicians, graduated from prestigious universities such as the University of Technology and the University of Transport. We provide comprehensive auto maintenance and repair services with the highest quality of service, meeting the increasing needs of customers.

We not only focus on repair but also provide car upgrade services such as Brightness increase, insulation film stickers, install dash cams and many other services. With the motto "Honesty - Dedication - Responsibility”, Thanh Phong Auto is committed to bringing maximum satisfaction to customers through a professional and effective maintenance process. Come to us to experience the most prestigious, quality and dedicated auto repair service!