How Radiator Works in Automobile? – Easiest Explanation

Here you can get Radiator Working Principle. Radiator also used in piston- engined aircraft, Railway, locomotives, motorcycles, stationary generating plants and other places where such engines are used.

Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics.

What is Radiator

Generally, a radiator is a heat exchanger this is used to transfer thermal energy from one medium to another for the essence of cooling and heating. Radiators are along with a huge location of the cooling surface and use the stream of air to take away the surrounding heat. with smooth get right of entry to to the coolant heat, efficient cooling is achieved.

Modern motors use aluminium radiators, but they generally made from copper and brass. This is because of their high heat conductivity. their various sections are joined by soldering.

It obvious radiator is important in automobile engines. One of its primary function is to allow heat to be blown away from the coolant. It additionally functions as a reservoir for coolant earlier than coming into the engine. that is why the malfunctioning of the element will cause significant engine damage caused by overheating.

The radiator is likewise used to cool the engine transmission system coolant.

Another exquisite feature of a few sort of radiator is that hot coolant is separated from the cold ones. Cold coolant stays at the bottom portion of the radiator even as the hot ones flow to the top. So, by it moving to the down portion the heat is already absorbed by the cooling fan’s air.

Working Principle of Radiator

A Radiator has a number of flat and thin pipes arranged horizontally one below the other.  Water flows through these pipes along their length. But how does the water flowing through these pipes gets cool so fast? So to increase the heat exchange from water to air, we have fins brazed between the flat surfaces of these pipes. These fins between the pipes look like a dense sine wave (trigonometric function). Thus increasing the surface area that comes in contact with air and increasing the heat exchange.

Parts of Radiators

Major Parts of a Radiator

Below are the major components of radiators and their functions:


The core is the major a part of a radiator that serve its main purpose. It is a metallic block with small metallic fins which through it the coolant heat is a vent to the air surrounding the radiator. Cores are used to classified radiators, for instance, one-core, two-core, or even three-core radiators.

Pressure Cap:

As the coolant in the radiator is always under pressure, which helps to maintain the coolant much hotter under with out boiling. This allows the system to be much more efficient. The function of the pressure cap is to bleed off the hot coolant since it rises at some point. The hot coolant could cause damage to the coolant components if the pressurize cap not functioning well.

Outlet and Inlet tank:

The outlet and the inlet part of the radiator are wherein the flows in and out of the radiator. It’s placed in the radiator head which is made of metallic or plastic. From the engine, hot coolant flows through the inlet portion to radiator and from the outer portion to the engine. The hose is used to make the connections.


Some motors use the equal cooler as the engine transmission cooler. In the transmission system, the fluid passes through a metallic pipe to ensure the coolant circulation. This coolant is likewise cooled inside the radiator because heat is also generated via an automatic transmission. Although some engines are designed with separate radiator for the transmission.

Types of Radiator

The various types of radiators are classified according to their core. Below are the types of radiator used in automotive engines:

Tubular Core Type:

In these types of radiator, the upper and lower tanks are connected by a series of tubes that passes the water within the radiator. There are fins location around the tube for efficient heat transfer. It absorbs the heat from the coolant through the fans to the atmosphere. Due to the fact water passes through all tube in this radiator type, defect on one tube will affect the cooling process.

Cellular Core Type:

In the cellular types of radiator, the coolant flows through the spaces between the tubes. The core is made of a large number of individual air cells surrounded by the coolant. Air passes through the tubes while the coolant flows in the spaces between them. The cellular core radiator is also known as honeycomb radiator because of its appearance. Unlike the tubular type, clogging in the tube affects a small part of the total cooling surface.

What is the function of a pressure cap in a Radiator?

Temperature of engine goes way much higher than 100 degree centigrade, and water is used as a coolant in cars. But the water starts boiling at 100 degrees and receives converted into steam. And steam does not exchange heat at a good pace. So how water may be used as a coolant.

To solve this problem pressure caps are introduced in a radiator.  Pressure cap does not allow the pressure formed in the radiator to escape created by hot water coming from the engine . Thus there may be an increase in pressure inside radiator as water get’s hotter. And as we know that the boiling point of a liquid increases if it is heated at a higher pressure.  So pressure cap increases the boiling point of water and maintains it in liquid state even at temperatures higher than 100 degree centigrade.  

Imagine if pressure in the radiator is going on increasing it could bust the radiator pipes, to short out this problem, pressure cap is equipped with a spring at its bottom, which gets lifted up as the pressure reaches around 15psi, so pressure cap acts as a valve and releases the pressure to overflow tank whilst it exceeds the limit of 15 psi.

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