Heater Core Functions in Car | How a Car Heater Works?

Car heater and heater core functions in car used fresh air and send this air to the passengers sitting inside the vehicle. In this article, I will talk about the heater core functions in cars. 

Heater Core Functions in Car

Heater Core Functions in Car

A car heater is used to heat fresh air directly inside the vehicle. In some designs, some of the hot water from the cooling system is directed to a small radiator, called a heater core, inside the car. One end of the radiator is connected by a hose to the engine water jacket and the other to the inlet side of the engine water pump to form a separate circulating system. 
Electric motor-driven blower fans, air inlets, and air exits serve to provide fresh air to be heated by the radiator and to be directed inside the car. Other car heaters’ designs burn gasoline from the fuel line to provide heat.
The heater core resembles a small radiator and is typically located beneath the dashboard on the passenger side. Its primary function is to generate heat to warm up the interior of the vehicle during cold weather. The functions are- 
1. Heating Function: The heater core works with the engine’s cooling system. As hot engine coolant flows through the heater core, the heat from the coolant is transferred to the surrounding air. The blower fan then pushes this warmed air into the cabin, providing a comfortable environment for the occupants.  The heater is a bunch of coils. 
2. Defrosting Function: Additionally, the heater core helps in defrosting the car’s windshield and windows during frosty conditions. When the defrost mode is activated, the warm air from the heater core is directed toward the windshield, preventing ice and frost from obstructing the driver’s view.

Heater Core Working Principle in Car

To know about the working principle of a car heater, it’s essential to understand the key elements involved in the process.

Engine Coolant:

The engine coolant, a mixture of antifreeze and water, circulates through the engine and absorbs excess heat to maintain the engine’s operating temperature.

Heating the Coolant:

As the engine operates, it generates a substantial amount of heat. This heat is transferred to the engine coolant, raising its temperature significantly.

Coolant Circulation:

The water pump in the engine ensures the continuous circulation of hot coolant. As the engine coolant leaves the engine block, it passes through the heater core.

Heat Transfer to Air:

The heater core consists of small tubes and fins, similar to a radiator. As the hot coolant flows through these tubes, the heat is transferred to the air passing over the tubes.

Blower Fan:

The blower fan, controlled by the car’s heating system, pushes the heated air into the passenger compartment.

Temperature and Airflow Control:

The driver can regulate the temperature and airflow using the car’s heating controls, ensuring optimal comfort for all passengers.
The working principle of a car heater revolves around the laws of thermodynamics and fluid dynamics. As the engine operates, it generates heat due to the combustion process.
The engine coolant absorbs this heat and carries it away from the engine to prevent overheating. This heated coolant then flows through the heater core, where the heat is transferred to the air, providing warmth to the car’s interior.
The continuous circulation of the engine coolant is maintained by the water pump. As the coolant passes through the heater core, it releases its heat to the surrounding air, making it comfortable for passengers inside the vehicle.

Types of Heater Cores

Heater cores come in various types. I have enlisted 4 of them for better understanding.
  1. Tube and Fin heater cores.
  2. Serpentine heater cores.
  3. Plate and fin heater cores.
  4. Multi Louvered heater cores.
I will give detailed information on these heater cores in the next articles. 


In conclusion, the heater core is a crucial component of a car’s heating and cooling system. Its functions of providing warmth during cold weather and aiding in defrosting the windshield are vital for passenger comfort and safety.


1. What is a heater coil in a car?
A heater coil is a bunch of a coil used for generating heat. In the Heater core, there is a bunch of coils available for a better heating process.
2. Why water pump is needed in a car?
Pumps are there for the circulation of objects. In a car, the water pump is there to circulate the coolant or water from the engine jacket to the radiator. 
Read more- 
Spread the love

Leave a comment