What Does Car Radiator Do? Definition, Parts, Function, Work, Types, Diagram

In this article, we will learn what is car radiator along with the Definition, Introduction, History, Components, Working, Types, signs of radiator failure, how to make your radiator last longer, Advantages, Disadvantages, Car Radiator FAQs. Let’s explore!

What is Car Radiator? Definition

Definition of Car Radiator

The car radiator is a device that keeps the engine at the correct operating temperature by moving coolant through a network of water channels that enable heat to be discharged, and it is regarded as a workhorse of the cooling system of a car.

what does car radiator do definition function parts work types diagram basics
What does car radiator do definition function parts work types diagram basics

Car Radiator Basics

Car Radiators are cooling systems that keep engines from overheating in cars. Car radiators are at the core of any vehicle’s cooling system. Car radiators are primarily responsible for keeping engines at the proper temperature so that they may work at their best. Car radiators, on the other hand, should not be confused with house radiators, which are used to heat dwellings.

Radiators are often made of copper, brass, or aluminum, and they consist of a system of pipes through which coolant circulates. The material of a radiator, on the other hand, is determined by its intended application and the many industrial radiator manufacturers.

History and evolution of car radiator

The first generation

In the first generation, Car radiators were composed of copper, and brass was used in all vehicles and trucks from the beginning of the automobile through the early 1970s. Nothing else could match with the metal’s tremendous benefits. Thus, there was no reason to use anything else. These car radiators were the gold piece of a car market in old times.

Also Read: Types of Cars

The second generation

 In the second generation, car radiators were environment altered. It happened in the 1970s. Volkswagen switched from an air-cooled to a water-cooled engine early in the decade. Following the global oil crisis and urgent requests for measures to cut fuel usage, major automotive manufacturers in Europe and the United States began producing lighter cars and trucks. For radiators, this meant aluminum, which is one-third the density of copper/brass and, despite its numerous flaws, can take heat quite well.

Aluminum is also less costly in its natural condition (albeit not as a radiator strip). These characteristics, along with commodities experts’ grave, if unfulfilled forecasts that copper/brass would be in limited supply in the 1980s, sparked a wave of anticipation for something new.

As a result, aluminum has overtaken copper/brass as the most popular metal for car radiators in new automobiles (56 percent vs. 44 percent), even though copper/brass still accounts for two-thirds of the entire radiator market. With 89 percent of the aftermarket market, copper/brass reigns supreme.

The third generation

 In the third generation, while aluminum’s use in new automobiles and trucks grew, the copper/brass industry began exploring methods to enhance the conventional copper/brass radiator to compete more aggressively against aluminum, which began to show various drawbacks as a car radiator metal.

Aluminum car radiators, for example, are significantly more expensive to repair when rusted or damaged than copper/brass radiators. Furthermore, pin-hole corrosion on the coolant side is particularly common in aluminum radiators. The car radiators were irreparably damaged if that used to happen.

The copper/brass business had found numerous new technologies that would make the difference in generating a lighter, stronger, and more durable copper/brass radiator by the early 1990s, even though the research required years to develop. Laser welding, no-flux (no lead) brazing, and electrophoretic coating are a few examples.

Using these technologies, the copper/brass industry has produced a new radiator that is lighter, more compact, and more durable than anything now in use globally, in collaboration with key vehicle and radiator manufacturers in the United States, Europe, and Japan. It might be accessible in automobiles as early as 1995 since it is now in the early phases of field testing.

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What Does Car Radiator Do? Function

High temperatures harm engine materials and lubricants, necessitating the usage of radiators. Internal-combustion engines burn fuel at temperatures that are hotter than the melting point of engine components and high enough to ignite lubricants. Engine cooling removes enough energy quickly to maintain temperatures low enough for the engine to live. A design known as adiabatic allows some high-efficiency engines to run without deliberate cooling and with just inadvertent heat loss.

For the Shell economy challenge, for example, 10,000 mile-per-gallon “cars” are insulated to transmit as much energy as possible from hot gases to mechanical action and to minimize reheat losses while restarting. High efficiency is possible with these engines, but power output, duty cycle, engine weight, durability, and emissions are all compromised to obtain more water.

Different Parts of Car Radiator

Automobile radiators are made up of two header tanks connected by a core with many thin tunnels, giving them a large surface area for their volume. This core is often made up of stacked layers of metal sheets that have been pressed into channels and then soldered or brazed together.

car radiator definition different parts Image: maplesoft

Radiators have been built from brass or copper cores soldered to brass headers for many years. Plastic headers and aluminum cores are used in modern radiators to save money and weight. This structure is more difficult to repair than typical materials.


While in operation, a car’s engine warms up continually, and if it approaches a dangerously high temperature, there is a chance of an explosion. As a result, it must be cooled to a reasonable temperature, such as between 80 and 100 degrees Celsius, and this is where the radiator comes in it assists in cooling the engine to the proper temperature.

Except for certain air-cooled or electric automobiles, such as the Nissan Leaf, most current engines are water-cooled. Here, we’ll look at the parts of a water-cooled car radiator and how to care for it. A car radiator coolant comprised of water circulates in the water jacket around a cylinder in a water-cooled engine to keep it from overheating. To improve the operation of the water pump in a water-cooled car radiator, a radiator is put in the center between the exit and intake.

 The radiator, radiator hose, water pump, thermostat, and cooling fan make up the entire system. Cores are a series of tiny tubes that allow car radiator coolant to circulate through the main body of the radiator. The goal is to increase the amount of water traveling through each core to increase the cooling effect. The radiator simply does not work—take let’s a closer look at each component of the radiator-related sections to better comprehend their functions. The radiator’s purpose is completed when these pieces are used together.

Also Read: What is Governer

Cooling fan

The car radiator fan is called a cooling fan. The temperature of the engine is decreased by fresh air while it is operating, but air cooling alone is insufficient for times when the engine is not in motion but still producing heat, such as during traffic jams. As a result, a car radiator fan becomes necessary. It improves the cooling effect by increasing the amount of airflow in front of the radiator to a desirable level. Cooling air is drawn via the radiator by the radiator fan (or fans).

Cooling fans or car radiator fans, which are located between the radiator and the engine, are especially useful when the automobile is parked or traveling at too slow a pace to drive air through the grille. Electric cooling car radiator fan, which turns on and off as needed, have shown to be superior to engine-driven fans, which slow down just when they’re needed the most. A faulty cooling car radiator fan can cause the engine to overheat. These car radiator fans can also serve as a source of cooling for the cabin air conditioning condenser.

Water pump

The car radiator water pump circulates coolant liquid in the water jackets around the engine, the radiator, and its sub-tank, ensuring that the cooled coolant in the radiator returns to a satisfactory level in the water jackets.

car radiator definition parts water pump
Car radiator definition parts water pump

A car radiator water pump is essential to the running of an automobile engine because it keeps the coolant moving through the engine block, cylinder head, hoses, and radiator at the proper temperature. A belt from the crankshaft pulley or sprocket normally drives it.


The thermostat aids in maintaining a constant coolant temperature within a set range. In very cold temperatures, it also shuts off the water supply to prevent coolants from flowing within the radiator. When an engine heats up, the water temperature rises with it, and when the coolant temperature reaches around 80 degrees Celsius, it fully opens a water outlet, enabling the coolant liquid to flow.

The thermostat is a valve that connects the engine to the radiator. This valve opens when the coolant in the engine becomes too hot, allowing it to pass to the radiator to cool down. The thermostat remains closed if it is not heated, enabling the coolant to circulate inside the block.

Also Read: What is Engine

Pressure cap

Because the coolant in the radiator is always under pressure, it can stay significantly hotter without boiling. As a result, the system is substantially more efficient. The car radiator pressure cap’s job is to drain out the hot coolant, which increases at some point. If the pressurized cap isn’t working properly, the hot coolant might harm the coolant components.

car radiator definition parts pressure cap
Car radiator definition parts pressure cap

When the cooling system’s fluid heats up, it expands, causing pressure to rise. Because the car radiator pressure cap is the only location where this pressure may escape, the maximum pressure in the cooling system is determined by the setting of the spring on the cap. When the pressure in the cooling system hits 15 psi, the pressure forces the valve open, enabling the coolant to escape.

 This coolant passes via the overflow tube and into the overflow tank’s bottom. This configuration prevents air from entering the system. When the radiator cools down again, a vacuum is generated in the cooling system, which causes another spring-loaded valve to open, pulling water back into the overflow tank from the bottom to replace the water that was lost.

Cooling water jackets

Around the cylinder, cylinder head, valve seats, and any other hot parts that need to be cooled, cooling water jackets are installed. The heat generated in the engine cylinder is transferred to the jackets via the cylinder walls.

car radiator definition parts cooling water jacket
Car radiator definition parts cooling water jacket

The heat is absorbed by the water running through the jackets, which heats up. After that, the hot water will be cooled in the radiator.

Outlet and inlet tanks of a car radiator

The smooth flow of the water into and out of the radiator is controlled by the outlet and inlet portions of the radiator. It may be found in either a metal or plastic radiator head. The hot coolant travels from the engine to the radiator through the intake area and back to the engine through the outer portion.

Antifreeze mixture

If the water used in radiators in western nations freezes due to cold conditions, the resulting ice has a larger volume and causes cracks in the cylinder blocks, pipes, and radiator. The car radiator antifreeze mixer or solutions are added to the cooling water to avoid freezing. Car radiator antifreeze solutions that are optimal should contain the following characteristics.

It is easily dissolved in water. It doesn’t go away. It does not cause any foreign stuff to accumulate in the cooling system. It has no negative impact on any aspect of the cooling system. It is inexpensive and widely available. It has no corrosive effect on the system.

Reserve tanks

Coolant expands as it heats up. Because the cooling system is sealed, this expansion results in a rise in cooling system pressure, which is standard and part of the design. When a coolant is under pressure, the temperature at which the liquid boils is much greater. This pressure, along with ethylene glycol’s greater boiling point, allows the coolant to safely reach temperatures beyond 250 degrees.

The radiator pressure cap is a basic mechanism that keeps the cooling system pressure constant up to a specified point. If the pressure rises over the specified pressure, a spring-loaded valve calibrated to the right pounds per square inch (psi) will open to relieve the pressure.

Also Read: Fuel Pump

Basic Principle of Car Radiator

Role of coolant

The car radiator principle involves air (a gaseous fluid) or a liquid coolant circulated through a heat exchanger (radiator) cooled by air is used to cool most internal combustion engines. Some stationary engines, like marine engines, have immediate access to a huge volume of water at an appropriate temperature.

Although water may be used directly to cool the engine, it frequently contains debris, which can block coolant tubes, as well as compounds, such as salt, which can harm the engine chemically. As a result, engine coolant might be circulated via a heat exchanger that is cooled by a body of water.

Water and chemicals like antifreeze and rust inhibitors are used in most liquid-cooled engines. Engine coolant is the industry term for the antifreeze mixture. Some antifreeze employs a liquid with different characteristics than water, such as propylene glycol or a mixture of propylene glycol and ethylene glycol.

Liquid and Air oil cooling

To keep essential engine parts and the oil at appropriate temperatures, most “air-cooled” engines employ some liquid oil cooling. Most “liquid-cooled” engines employ some air cooling, with air cooling the combustion chamber during the intake stroke. Wankel engines are an exception, as some portions of the combustion chamber are never cooled by intake, necessitating more effort for proper operation.

Cooling is influenced by the qualities of the coolant (water, oil, or air). When comparing water and oil as coolants, for example, one gram of oil can absorb around 55 percent of the heat for the same temperature rise (this is known as the specific heat capacity).

Requirements for air cooling

  • As oil has a density of around 90% that of water, a given amount of oil can only absorb about 50% of the energy that the same volume of water can.
  • Water has a thermal conductivity of around four times that of oil, which can help with heat transmission.
  • Oil’s viscosity can be ten times that of water, increasing the energy required to pump oil for cooling and lowering the engine’s net power output. When comparing air and water, the air has a lot lower heat capacity per gram and per volume (4000) and a tenth of the conductivity, but it also has a much lower viscosity (approximately 200 times lower: 17.4 106 Pa for air versus 8.94 104 Pa for water).
  • Continuing the computation from the previous two paragraphs, air cooling requires ten times the surface area, which necessitates the fins, and air requires 2000 times the flow velocity, necessitating ten times the power of a recirculating water pump.
  • Moving heat from the cylinder to a wide surface area for air cooling can pose challenges, such as creating the geometries required for efficient heat transfer and providing enough room for a big volume of air to flow freely.

How Does Car Radiator Work? Diagram

Let’s use try to understand how does car radiator work?

how does car radiator work
How does car radiator work? Image: mapplesoft

Role of aluminum radiators

These Aluminum radiators are used in the majority of modern automobiles. Brazing tiny metal fins to flattened aluminum tubes create these radiators. The coolant circulates in a series of parallel tubes from the input towards the exit. The heat from the tubes is carried to the air passing through the car radiator by the fins. A turbulator is a type of fin that is occasionally added into the tubes to increase the turbulence of the fluid passing through them.

Flow of fluids

The fluid flows smoothly through the tubes. The amount of heat transmitted to the tubes from the fluid going through them is determined by the temperature differential between the tubes and the fluid that comes into contact with them. As a result, if the fluid contact with those tubes cools rapidly, less heat is delivered. By forming turbulence inside the tube, all of the fluid mixes, maintaining the temperature of the fluid hitting the tubes high enough to extract additional heat, and all of the fluid inside the tube is successfully employed.

Fins like structures

The fins-like structures inside the radiator pipes of high-end automotive radiators are a bit more complicated. These are used to add turbulence to the water that flows past them. Water running through pipes with no internal fins is called streamline water. As a result, heat will be exchanged between the outer layer of water and the air.

Role of temperature difference

 As the temperature difference between air and water decreases as the outer layer of water cools, the rate of heat exchange decreases. Water molecules that exchange heat with air get mixed up with hot water in radiator pipes with internal fins due to turbulence caused by these fins. As a result, the temperature of the entire body of water remains consistent and high.

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Transfer of heat

 This allows for a higher quantity of heat to be transferred, allowing the coolant to cool at a much faster rate. The temperature of an engine may reach well over 100 degrees Celsius; therefore, water is utilized as a coolant in automobiles. However, at 100 degrees, the water begins to boil and is turned to steam. Steam, on the other hand, does not exchange heat quickly.

Use of pressure caps

Pressure caps are used in radiators to overcome this problem. The pressure developed in the radiator by hot water from the engine is not allowed to escape through the pressure cap. As the water inside the radiator heats up, the pressure inside the radiator rises. And, as we all know, when a liquid is heated at a higher pressure, its boiling point rises.

As a result, the pressure cap raises the boiling point of water and maintains its liquid even at temperatures above 100 degrees Celsius. Imagine that if the pressure in the radiator continues to rise, it could burst the radiator pipes.

Role of spring as a valve

 To avoid this, the pressure cap has a spring at the bottom that lifts as the pressure rises to around 15-psi. As a result, the pressure cap acts as a valve, releasing the pressure to the overflow tank when it exceeds the 15-psi limit.

What is the Purpose of Transmission Oil?

Have you ever heard of transmission oil, which is utilized in the transmission and power steering, being pumped into the radiator? We must cool the transmission oil in high-payload automobiles, and we do so by using our radiator to take the heat from the oil. The hot side of the radiator’s intake port is named after the hot water that enters from the engine.

As the water passes through pipes and cools, it exits through the cold side of the radiator’s outlet port. So, on the cool side of the radiator, we have a cylindrical structure through which transmission oil flows and exchanges heat with cold water.

Also Read: Diesel Engine

Types of Car Radiator

Tubular Radiator

Water runs through a series of higher and lower tanks. To increase the efficiency of heat transmission, fins are installed on the tubes. The fins that absorb heat from the water outside of the tubes are connected by air that circulates between them. Because the water circulates through all of the tubes, if one becomes clogged, the entire tube loses its cooling function.

In a cellular radiator, each obstruction of a tube results in a small amount of the overall cooling surface being lost. Because the water in a tubular radiator goes through all of the tubes, if one becomes clogged, the entire tube loses its cooling ability. The loss of a small fraction of the overall cooling surface occurs when any route in the cellular radiator is obstructed.

Cellular Radiator

In a cellular-like core, air moves through the tubes, and water flows through the gaps. The core is made up of a massive number of water-encased air cells. Due to its appearance, the cellular type is often known as a honeycomb radiator, most of the time when the cells in front are in the shape of a hexagon. The loss of a small fraction of the overall cooling surface occurs when any route in the cellular radiator is obstructed.

What are the Signs of Radiator Failure?

When an engine is running, it generates heat. The radiator’s job is to keep the engine cool and prevent it from overheating. Coolant is used by a car’s engine to absorb heat and send it to the radiator, where it is cooled. The coolant is returned to the engine once it has cooled, and the process begins all over again. There isn’t enough cooling within the engine when the radiator is blocked, not performing as efficiently as it could, or has simply failed.

This can lead to your automobile overheating and, if not addressed quickly enough, irreparable damage to the engine’s internals. Radiators can become blocked from the inside, the outside, or they might just stop working. Here are some warning signs of a blocked radiator to watch for before your engine suffers costly harm.

Temperature change

Check the thermometer to see if the readings are higher than normal or if the needle is in the “red” zone. Some contemporary cars will display the temperature digitally and alarm you if it becomes too high. Temperatures in most vehicles usually range from 195 to 220 degrees Fahrenheit. If the temperature falls slightly outside of that range, it’s usually not a cause for concern, especially in the summer when the air conditioner is always running.

As a result, if the temperature stays high for an extended period of time, you may have a clogged radiator. This is frequently caused by rust corrosion, internal deposits that build up over time, or debris caught in the radiator, which prevents the required amount of coolant from passing through the radiator and into your engine.

Rust accumulation

When the radiator is blocked owing to excessive rust accumulation, the housing or cooling fins may develop microscopic holes or splits. If this happens, you may see small drops of ar radiator coolant on your driveway or garage floor. Rust inside your radiator is frequently caused by using a low-quality coolant or adding normal tap water (rather than distilled) to the coolant mix, which contains far more impurities.

If a radiator flush is not performed regularly, rust will build up and begin to eat away at the radiator tank. Your car will be forced to function with inadequate coolant if there is even the tiniest coolant leak, and the low coolant level indicator in your dash may illuminate. Your engine may overheat and require expensive repairs if you don’t remedy the leak as soon as possible (or at the very least maintain the coolant level topped off).

Pollution caused by muck

Radiator in a vehicle coolant should be brightly colored, such as green, yellow, or orange (but not always), and flow freely through the radiator and coolant tubes within the engine. Internal deposits, such as mud, can cause the coolant to become badly polluted over time. The color will turn rusty brown as a result.

The only straightforward approach to inspect the coolant’s condition is to use the overflow tank. This contaminated fluid will be thicker and more difficult to move through the cooling system. This clogs the radiator, and if it becomes bad enough, the radiator’s efficacy can be reduced to the point where your automobile overheats more than usual.

Because it’s critical to keep the radiator clean, a radiator flush should be done as soon as possible. In some autos, the gearbox cooler is also housed in the radiator. If the barrier between the two leaks is broken, the coolant and transmission fluid will combine, causing double the issues.

Clogging of tubes

Radiators for automobiles are designed to give the maximum amount of cooling. This is accomplished by thin fin tubes passing over the radiator’s front. The heated coolant travels through these tubes. While driving, the radiator fan blasts outside air into and through these fins, decreasing the coolant temperature before it returns to the engine.

The airflow becomes hindered when these tubes become clogged with dirt, bugs, leaves, or other material, preventing the coolant from cooling as quickly as it could. Most cars have adequate access (you may have to remove a few plastic covers) to clear any dirt from the front of the radiator with a garden hose and spray nozzle.

Radiators for automobiles are designed to give the maximum amount of cooling. This is achieved by thin finned tubes that run over the front of the radiator. The heated coolant travels through these tubes. While driving, the radiator fan blasts outside air into and through these fins, decreasing the coolant temperature before it returns to the engine.

The airflow becomes hindered when these tubes become clogged with dirt, bugs, leaves, or other material, preventing the coolant from cooling as quickly as it could. Most cars have adequate access (you may have to remove a few plastic covers) to clear any dirt from the front of the radiator with a garden hose and spray nozzle.

Hindrance of airflow

In addition to blockage caused by extraneous material stuck to the front of the radiator, airflow can be hampered if enough fins are bent or damaged. These fins are extremely delicate, and even a small particle of dirt flashing by them while driving can damage them. This damage can also happen when a new radiator is installed or when the fins are cleaned with water.

If there is too much water pressure applied, such as when using a concentrated stream or pressure washer, the fins can readily open and restrict the passage of air. The radiator may become clogged to the point where the engine overheats if enough fins are destroyed.

Problematic thermostat

The cabin heater in a car works by sending heated coolant through the heater core and then blasting it into the passenger compartment with a blower fan. If the radiator is clogged and not enough coolant reaches the heater core, the car’s interior will not be adequately warmed. The most common cause of this condition is a malfunctioning thermostat. However, a radiator issue could also be to blame.


If your radiator is working properly, the top radiator hose will be extremely hot to the touch, but the bottom hose will just be warm as the coolant goes through the radiator. However, if you find that the lower radiator hose is chilly after a while, your radiator may have a clog that prevents the entire flow amount from returning to your water pump.

How to make your radiator last longer?

Coolant designed radiators

Use only coolants designed for your car’s make and model, and never mix coolants. Aluminum and copper-brass radiators may have differing needs, and the standard coolant may not be sufficient.

Radiator flush and engine coolant change

A radiator flush and engine coolant change every 12 months or 30 000 miles will eliminate the build-up of corrosion and grime and keep your radiator in good operating order.

 Look for leaks and breaks

 When you replace your car’s oil, look for leaks and breaks in the radiator hose. Check for rusty clamps and check sure the gasket on your radiator top is still in good shape. Look under the engine for obvious indicators of leaks or drips.

Keep coolant levels in check

It’s critical to keep coolant levels in check. It will not only prevent your vehicle from overheating in hot weather, but it will also prevent fluids from freezing in extremely cold conditions.

Radiator inspection

To avoid high costs, service your automobile and inspect your radiator regularly. This allows you to maintain proper antifreeze levels, preventing water from freezing or boosting the boiling point of engine coolant, preventing overheating. If your car’s engine and cooling system are well-maintained, a radiator should last a long time. Your vehicle’s engine might seize if it overheats, costing you a lot to replace.

Load on the engine

The more weight your vehicle carries, the more cooling your radiator needs to conduct. As the load on the engine is increased, overloading is a key cause of overheating. Follow the manufacturer’s guidelines for your vehicle’s maximum load. If you’re tempted to overload, consider driving at high speeds with an engine that has overheated and a disconnected belt that can’t drive the power steering pump.

In this situation, your brakes may potentially fail. Every week, check and maintain the water level in your radiator. When your radiator is at working temperature, don’t top it up with cold water. Allow your automobile to cool before adding water if required.

Advantages of Car Radiator

  • The car radiator exchange heat dissipates heat effectively. It is self-evident that it saves both material and energy.
  • Excellent corrosion resistance to oxidation
  • They have a high level of responsiveness.
  • They are less polluting since they are produced in an ecologically sustainable manner.
  • They’re simple to shape, so you can come up with some very creative and weird patterns.
  • They are made of ceramic, cast iron, and other heat-resistant materials.

Disadvantages of Car Radiator

  • Heat loss occurs if the system is not properly used and maintained.
  • The operation is noisy.
  • 3)      For a radiator to function correctly, there must be sufficient airflow in the space.
  • The heat from the unit will merely sit around the unit, reducing comfort levels and causing draughts and cold areas in your house.
  • While functioning, radiators can get quite hot to the touch. Please keep young children and pets away from the functioning radiator.

Frequently Asked Questions FAQs

What indicates a radiator failure?

The steam that exits the radiator and excessive heating of the car indicate a radiator failure.

When should a person change or replace his car radiator?

The car radiator has a good lifespan of 8 years, but still, if a person feels that the car radiator coolant is leaking, he should immediately replace the radiator.

Is replacement necessary for a car radiator?

Yes, a car radiator should be replaced immediately after it’s deceased or faulty because it can burn your engine. You are making it cease permanently. It can also damage the petrol tube of the car which can cause a serious disaster.

What should a person care for while buying coolant for his radiator?

The coolant should be selected based on its peak performance. When we choose a faulty coolant, it causes corrosion which reduces the life span of a car radiator.


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