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How Does a Car Radiator Work? (Explained)

Updated: Feb 2

✔ This article has been fact checked.

A car radiator is a heat exchanger that is designed to transfer heat from the hot coolant (a mixture of antifreeze and water), which circulates through the engine, to the air that is blown through the radiator (a network of tubes and fins) by the radiator fan and the vehicles movement.

Coolant is pumped through the engine by the water pump, absorbing heat from the engine block and other components, before flowing into the radiator, where it is cooled by the airflow from the radiator fan or the cars movement.

In this article, we will take a closer look at how a car radiator works and the various parts that make up a car's cooling system.

Table of Contents:

car radiator

What Is a Car Radiator?

A car radiator is a type of heat exchanger, it is made up of a series of tubes and fins and is designed to dissipate heat from the hot coolant to the ambient air.

It is a type of liquid-to-air heat exchanger. Nearly all internal combustion engines have a form of heat exchanger, usually in the form of a radiator.

What Does a Car Radiator Do?

The basic principle behind the operation of a car radiator is that heat is transferred from the hot coolant to the cooler air that is blown through the radiator.

As the hot coolant flows through the thin tubes of the radiator, the heat is transferred to the fins, which act as a heat sink, dissipating the heat into the surrounding air.

The coolant then flow back to the engine, where it picks up more heat and the process repeats. As the engine warms up, the thermostat, which is a temperature-sensitive valve, opens, allowing coolant to flow through the engine and the radiator.

As the engine cools down, the thermostat closes, reducing the coolant flow and preventing the engine from running too cold.

diagram of a car radiator

Parts of a Car Cooling System

A car's cooling system is made up of several different parts, including the following.

  • Coolant: The fluid that circulates through the engine and the radiator, absorbing heat as it goes. It's a mixture of water and antifreeze, which prevents the coolant from freezing in cold weather and boiling in hot weather.

  • Radiator: The main component of the cooling system, responsible for dissipating the heat from the coolant into the ambient air.

  • Radiator Fan: A mechanical or electronic fan that blows air through the radiator, helping to dissipate the heat into the surrounding air.

  • Thermostat: A temperature-sensitive valve that regulates the flow of coolant through the engine and the radiator.

  • Water Pump: A mechanical or electronic pump that circulates the coolant through the engine and the radiator.

diagram showing car parts of the cooling system and how it works


A car radiator is a crucial component of a car's cooling system that helps to keep the engine from overheating. It works by passing coolant through a network of tubes and fins, which dissipate the heat generated by the engine.

The coolant is circulated through the engine and the radiator by the water pump and is cooled by the airflow from ambient air.

The thermostat regulates the flow of coolant to maintain the appropriate engine temperature. Understanding how the car's cooling system works is important for keeping the engine running smoothly and prolonging the lifespan of the vehicle.


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