7 Parts of a Cooling System (and Their Functions)

The internal combustion engine has explosions inside of it regularly. Think about when you’re stepping on the gas pedal to accelerate quickly. How is the engine creating all that power for your vehicle to move faster?

There are an estimated 4,000 explosions taking place inside your engine every minute if you have a 4-cylinder engine and traveling at 50 mph. This is the process where the air and fuel mixture is ignited by the spark plugs to generate the power needed to move the wheels underneath your vehicle.

When you have so many explosions taking place this quickly, there is a lot of heat generated in the engine. These high temperatures could permanently damage the engine within minutes. The only thing which stops this from happening is the car’s cooling system.

The cooling system lowers the temperatures in the engine so that it doesn’t suffer any damage. Instead, it keeps the engine cooled enough to where it can keep operating smoothly.

Do not confuse the cooling system with the air conditioner because they’re actually two different systems in the car. The cooling system focuses specifically on cooling the engine, while the air conditioner focuses on cooling the people inside the vehicle.

If you had to choose which one was more important, then it would have to be the cooling system. You could possibly survive without air conditioning, but you cannot survive with a cooling system for your engine. If your cooling system doesn’t work, then your engine will die quickly.

See Also: 142 Different Car Parts (w/ Pictures)

Car Cooling System Components

There are several different parts that make up the car cooling system. Below is a list of the components of a car cooling system.

1) Electric Cooling Fan

cooling fan

This component helps circulate the coolness within the engine. The fan only comes on if the engine gets to be 230°F or more. Any vehicle that is front wheel drive with a transversely mounted engine is bound to have an electric cooling fan.

2) Fan Clutch

fan clutch

When the radiator has air flowing through it, the fan clutch detects its temperature. Based on the temperature reading, the fan clutch pulls in the necessary amount of air into the radiator.

3) Thermostat

bad thermostat

The cooling system uses a thermostat to regulate the normal running temperature of the internal combustion engine. When you first start your engine, the temperature is still cold, so the thermostat won’t activate yet. This allows the engine to warm up quickly.

Once the engine reaches its standard operating temperature, the thermostat activates. Then coolant is able to enter the radiator.

It’s fairly common for a car thermostat to fail. Fortunately, the cost to replace a thermostat is on the lower end when it comes to car repairs and it’s a fairly simple DIY job as long as you can follow directions.

4) Hoses

upper radiator hose

Most of the components of the cooling system are connected by a series of hoses. That is how coolant fluid is able to circulate. Even if a radiator hose is in good condition, the hose can collapse under certain situations leading to overheating.

5) Heater Core

heater core

When you turn on the heater in your vehicle, the heater core is responsible for producing the heated air that you feel. It produces this air by taking the heat that is extracted from the coolant and blowing it into the cabin.

6) Water Pump

bad water pump

When the coolant fluid is cooled after being in the radiator, the water pump sends the fluid back into the engine block, heater core, and cylinder head. Eventually, the fluid reenters the radiator where it is cooled off again.

Read Also: 4 Symptoms of a Bad Water Pump and Replacement Cost

7) Radiator

car radiator

Coolant fluid heats up after circulating through the hot engine block. When the coolant enters the radiator, it is cooled off and then sent back into the engine block to re-cool the engine.

Read Also:  5 Symptoms of a Bad Radiator and Replacement Cost


Each one of these components is crucial for sustaining the functionality of the cooling system. If just one of them were to break, it would affect the entire cooling process of the engine.


14 thoughts on “7 Parts of a Cooling System (and Their Functions)”

  1. My Toyota Corolla 2000 model gave me serious issues recently. Changed the radiator, radiator cap, head gasket was also replaced. Still water in my radiator keeps getting low on a daily basis. Alas, it was the heater core that was the problem, it was changed and right now, no more overheating, low coolant level in the radiator.

  2. Hello, we just replaced the radiator, water pump, fan clutch, radiator cap, checked hoses, put new coolant in, removed the thermostat (for the time being), checked the fan by trying to turn the blades (could do this before very easily but can’t now that the clutch has been replaced). Any ideas why it would still be overheating?

    • It could be air in the cooling system, a head gasket leak, or an intake manifold gasket leak (if your intake manifold has water jackets). A leak down test may help narrow the problem down.


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