Car Engine Cooling System Components

The car engine cooling system components functions to reduce the engine temperature and prevent overheating. There are two sets of engine cooling systems: water and air.

Usually, car engines use a water cooling system even though this system has disadvantages such as complicated construction and expensive costs compared to the air conditioning method.

the cooling system of a car engine


The advantage of a Water cooling system is that the cooling time is faster and safer because water surrounds the combustion chamber. 
Other functions are as sound dampers, vibration-dampers, and as a heat source for heaters.
Now, how does a car engine cooling work? A car engine is an inner combustion powerhouse. It generates power through an expansion of pressure gases and high temperatures.
A lot of heat is formed right to the combustion gas and the friction of mechanical parts for continued work. These excess temperatures should be discharged from the engine and maintained at functioning heat.

Car Engine Cooling Components

The main parts for cooling the engine are the water pump radiator, thermostat coolant temperature sensor, and coolant.

Water Pump

The water pump acts as the core of the auto cooling system to pumps the coolant. It comprises an o-ring, an impeller, and a pulley flange. The motor drive belt turns the impeller through a pulley.


The radiator is a temperature exchanger utilized to carry too much heat generated by the engine to the environment. The car radiator has an inlet-outlet port, a waste plug, and a radiator pressure cover. The radiator pressure cover acts as a vital part of the cooling cycle.


The thermostat is a valve that controls the movement of the coolant and serves to support the proper working heat for the engine. The thermostat consists of a frame charge cylinder, main valve, mainspring, bypass valve, and secondary spring.

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Coolant Temperature Sensor or CTS

CTS is used to observe the engine heat. The ECU will use these details to control combustion events and the process of fuel injection.

Any engines have at least one coolant temperature detector or more and use it to control the radiator fan or refresh the driver console’s temperature measurements.

The crucial components of the coolant heat sensor are a sensing probe and an electrical connector. Most coolant temperature sensors are a negative temperature factor type, which indicates that the resistance will reduce as the heat rises.

A two or 3-pin model can build the CTS structure. It depends on carmakers, and these are vital main parts of the engine cooling system.

How do Engine Cooling Components work?

How these parts work together? The engine block contains pistons inside, which each of them will function.

Above the engine block, there is a head gasket, which provides sealing between the head and the engine block. This prevents compression leaks and coolant or oil leaks toward the cylinder.

Over that, there’s the crucial engine head.  The engine has a secure entrance through which the coolant can flow without mixing up with the oil or penetrating the cylinder. This essential passage is known as a water jacket.

Let’s put the parts one by one, and you’ll know how it works. The water pump elevates the coolant across the system with the radial impeller’s assist, and the engine handles it utilizing a serpentine belt. 

The serpentine belt further turns the pump of the power steering alternator of the air conditioner condenser.

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Connections In Engine Cooling System

Now let’s see the links where all makes the cooling system works.

The engine cooling system components are:

  • thermostat bypass hose
  • A thermostat inside the housing.
  • radiator and the radiator fan
  • lower radiator hose
  • water pump outlet hose
  • upper radiator hose
  • coolant expansion tank
  • expansion bleed hose
  • coolant overflow hose

So finally, let’s get into the working, starting with the thermostat. The thermostat is a valve that regulates the flow of the coolant.

It will always be covered in the coolant so it can detect the actual temperature.

Let’s talk about the operation of a cold engine. 

When the engine is cold, the bypass valve stays open.

So the coolant circumvent is the radiator and recycles over the engine, which eases the car engine to instantly warm up to working temperature.

Ultimately, the coolant heat grows by receiving the heat from the engine.

Once the coolant begins to enter the hot temperature, generally within 160 to 190 Fahrenheit, the bypass valve will start to lock, and vice versa, the main valve will open. 

As a result, the cold coolant from the radiator stream to the car engine side, and the hot coolant from the automobile engine side stream to the car radiator.

In most cars, you will notice the coolant heat sensor near the thermostat housing.

It will initiate the radiator fan if the coolant to the radiator side is at a hot temperature. The hot coolant liquid in the radiator will discharge its high temperature to the air with the blower’s support.

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Simultaneously, the cold coolant derived from the radiator will begin to receive the engine’s heat for the following sequence. The heating fluid inside a sealed system always raises the pressure.

So, how to control the pressure? Here we go, the use of the radiator pressure lid.

It consists structure of a spring-loaded valve mechanism that will respond to higher pressure.

In case entering high pressure, more than 15 psi, it will force the pressure cover valve and the coolant streams to the expansion tank until the pressure drop to the work scale.

When the operation is cooling down the inner vacuum, the system will suck back the liquid from the expansion tank.

If there is excessive pressure accumulated in the system due to trapped air or other malfunctions, the expansion tank’s coolant will be pushed out by the overflow line.

The Heater in the Engine cooling system components

The car heaters are a part of the well-known engine cooling scheme. The heater system comprises the heater core inlet and outlet hoses, a heater control valve, optional, and you can’t find it in most vehicles.

The heater heart serves as a radiator removing heat from the high temp coolant to the car interior utilizing a blower.

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