Engine Cooling System In A Car Explained!

Engine Cooling System

The video explains how a car’s closed-loop engine cooling system prevents overheating and helps the engine reach and maintain an appropriate operating temperature. Most modern car engines use liquid cooling, though some smaller or specialized engines may use air cooling. Engine oil also carries away some heat.

During combustion, temperatures in the chamber can reach roughly 1,500–2,000 °C. Coolant circulates through passages in the engine block and cylinder head, where it absorbs heat. The hot coolant then flows to the radiator, where airflow cools it before it returns to the engine. The video says the system is designed to remove at least 30% of combustion heat while retaining engine thermal efficiency.

Main Functions

• Prevent excessive engine heat from damaging or melting components.
• Help regulate oil temperature. Overheated oil can oxidize, form carbon deposits, and contribute to piston seizure.
• Dissipate heat when the engine is hot, while also allowing it to warm up to its operating temperature after startup.

Main Components

• Radiator: Uses tubes and fins to transfer heat from the coolant to the air flowing through it.
• Cooling fan: Increases airflow through the radiator to improve cooling.
• Pressure cap and expansion tank: Accommodate coolant expansion and help maintain system pressure. A spring-loaded valve releases excess fluid when pressure exceeds its set limit.
• Water pump: Circulates coolant through the engine and cooling system, typically using an impeller.
• Thermostat: Regulates coolant flow according to engine temperature and opens to send coolant to the radiator once the engine reaches a set temperature.
• Heater core: A small radiator that uses hot coolant to provide heat inside the vehicle.
• Hoses and branch pipes: Carry coolant between the engine, radiator, and other system components.
• Bypass system: Allows coolant to circulate around the radiator when the thermostat is closed, helping the engine warm up and maintain temperature balance.

Cooling Cycle

1. The water pump moves coolant through passages in the engine.
2. The coolant absorbs heat from the engine.
3. Once the thermostat opens, hot coolant flows through hoses to the radiator.
4. Air passing through the radiator cools the coolant; the fan can increase airflow.
5. The cooled liquid returns to the engine, and the cycle continues.

Speakers and Sources

• Speaker: One unnamed narrator.
• Source/channel: Student Lesson, the channel identified in the video metadata. No other speakers or cited sources are identified in the subtitles.