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Car Radiator: Function, Design & How It Works (Explained)

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Last Updated on: 7th September 2023, 12:36 am

The car radiator is a vital part of a vehicles cooling system, it’s a form of heat exchanger and it’s responsible for transferring heat from the coolant fluid to the outside air.

Ambient air flows through its core, over the fins and cools down the coolant fluid flowing through it, regulating its temperature and keeping it within a specific range.

In this article, we’ll discuss how a car radiator works, its design, and its importance in the cooling system.

car radiator graphic


An internal combustion engine generates lots of heat during its operation. This heat comes from the combustion process and via friction from moving parts.

This heat must be regulated and dissipated, which is the job of a cars cooling system and the radiator. A consistent operating temperature is crucial for engine performance and durability.

Radiators, similarly to intercoolers, are a type of air-cooled heat exchanger, in which they transfer heat to the outside air flowing though it via a series of tubes and fins.

Components of the Cooling System

The cooling system is a group of parts that work together to keep the engine temperature within a certain range, usually between 190 to 225 degrees Fahrenheit (75 to 105 degrees Celsius).

These components include the:

  • water pump
  • thermostat
  • radiator
  • cooling fan
  • hoses
  • coolant fluid
diagram showing how a car radiator and cooling system works

How Does the Radiator Work?

Below shows the process of how the radiator regulates coolant fluid temperature.

  1. Coolant absorbs heat from the engine as it circulates through the engine block and cylinder head.
  2. The thermostat regulates when coolant flows to the radiator based on coolant temperature.
  3. The hot coolant flows into the radiator hoses, through the inlet tank and distributed through a series of tubes in its core.
  4. Radiator fins facilitate the transfer of heat from the tubes to the surrounding air through conduction and convection.
  5. The cooling fan increases airflow when the vehicle is stationary or operating at elevated temperatures.
  6. As the coolant releases its heat, it returns to the engine to repeat the cycle.


At the heart of the cooling system lies the radiator, usually placed at the front of the car by the grille to improve airflow.

The radiator’s core is composed of numerous small tubes and fins that promote efficient heat exchange.

As heated coolant flows through the radiator, the heat is transferred to the fins and subsequently dissipated into the surrounding air.

diagram showing the parts of a car radiator

There are multiple parts of a car radiator, including the:

  • End tanks (inlet and outlet)
  • Gaskets
  • Radiator core
  • Filler neck and cap
  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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