If your engine isn't cooling properly, bad things can happen. Parts wear out faster, more harmful substances are released into the air, and worst of all, your engine becomes less efficient.

That's why the cooling system is so important. It's like a superhero, ready to save your engine and keep it warm.

The job of the cooling system is to ensure that the engine maintains an ideal temperature. If any part of the system fails, the engine will overheat, which can cause problems.

The head gasket can blow, the engine body can crack, and the high temperatures can even cause the piston to stick to the cylinder. Ouch! Trust me, you don't want to be in this situation. It's like saying goodbye to your engine and then having to spend a lot of money to buy a new one.

For this reason, it's crucial to maintain your engine cooling system and understand how it works. Use the cooling system correctly to keep your engine cool and in good condition during long journeys.

What is a Cooling System?

The engine cooling system of your vehicle not only keeps the engine cool, but also keeps it hot enough to ensure efficient and clean operation.

System components include a radiator to dissipate heat, one or more fans to ensure adequate airflow to the radiator, and a thermostatic valve that opens and circulates the coolant through the engine when the required operating temperature is reached.

To do this, a water pump (or coolant pump) and other components are required. Most vehicles today use an expansion tank that allows the coolant to expand and flow out of the cooling circuit when the vehicle is hot and when the vehicle is stopped and the engine is cool.

The cooling system also includes elements of the cabin ventilation system, as engine heat is used to heat the interior of the vehicle.

How does a car's cooling system work?

The cooling system is a system of parts and fluids that work together to control the operating temperature of the engine for optimal performance.

The system consists of passages in the engine block and cylinder head, a water pump and belts to circulate the coolant, a thermostat to control the coolant's temperature, a radiator to cool the coolant, a radiator cap to control the system pressure, and hoses to transfer the coolant from the engine to the radiator.

The fluid that flows through the cooling system, antifreeze, or coolant as it’s commonly called, can withstand extreme hot and cold temperatures and contains rust inhibitors and lubricants to keep the system running smoothly.

The coolant’s circulation path begins at the water pump. The water pump impeller uses centrifugal force to pull the coolant from the radiator and push it into the engine block. The water pump is usually driven by a fan, serpentine timing belt, or timing chain.

Today, water pumps can even be electrically powered. If the water pump has a leaking seal, a cracked housing, a damaged impeller, or a bearing failure, it can compromise the entire cooling system and cause the vehicle to overheat.

As the coolant flows through the system, it absorbs heat from the engine before it reaches the thermostat. The thermostat is a valve that measures the coolant’s temperature and opens the thermostat to allow the hot liquid to flow to the radiator.

If the thermostat becomes “stuck” and stops working, it affects the entire cooling system. Once the thermostat is loose, the hot coolant flows through the hose to the radiator to cool it. Antifreeze flows through a thin tube in the radiator.

The radiator is cooled when air flows over the outside of the tubes. Air flow is provided by the vehicle in motion (ram air effect) and/or the cooling fan, depending on vehicle speed. Restrictions in the radiator affect its ability to transfer heat. These restrictions can be external air flow or internal coolant flow restrictions.

A faulty electric cooling fan or fan clutch can restrict the amount of air flowing through the radiator. Check/replace fan clutch… The water pump and fan clutch have roughly the same life expectancy and share a common shaft.

A faulty fan clutch can cause serious damage to the water pump. As the coolant temperature increases, so does the pressure within the cooling system. This pressure is regulated by the radiator cap. Correct system pressure is necessary for lubrication of the water pump seals.

Increasing cooling system pressure raises the boiling point of the coolant. For every pound (about 1.5 kg) of pressure increase, the boiling point increases by 3 degrees Fahrenheit (about 1 degree Celsius). If the pressure exceeds the set pressure point, a spring-loaded valve in the cap releases the pressure.

If the engine overheats, the radiator cap and thermostat should be replaced. It is important to regularly check the condition of the cooling system belts and hoses. Too soft hoses, oil-soaked belts, or cracked belts and hoses can wreak havoc on your entire cooling system.

Proper belt tension is also important. Always refer to the manufacturer's manual to determine the recommended coolant type for your vehicle. Coolant and the proper coolant and distilled water mixture are key to keeping your system running cool.

Most parts retailers now offer a premixed solution of coolant and distilled water. While this may seem like an unnecessary extra expense, the cleanliness of the premixed solution will pay off in the end. Mineral deposits and sediment from corroded or malfunctioning components can accumulate in the cooling system.

Before performing cooling system repairs, it is recommended to flush the cooling system before installing any new parts. Using a flush fill kit can make this job much easier. Failure to flush the system can contaminate new parts being installed and can cause premature failure of components.

Cooling System Components

The main components of the cooling system are the water pump, antifreeze plugs, thermostat, radiator, cooling fan, heater core, pressure cap, overflow tank, and hoses.

1. Cooling fan.

The cooling fan is located at the very front of the vehicle and kicks on when the coolant (which we'll talk more about later) starts to get too hot. Once the coolant cools down, the fan turns off.

2. Radiator.

The heated coolant flows into the radiator inlet and passes through a series of pipes and fins that effectively dissipate the coolant's heat.

3. Water Pump.

The water pump is considered the "heart" of the cooling system and is usually located at the front of the cylinder block. A hose carries the cooled coolant from the radiator to the water pump.

A belt or chain rotates the water pump shaft, and the coolant enters the center of the water pump. The water pump's impeller has fan-like blades, and the rotation of the impeller creates centrifugal force that moves the liquid outward.

The coolant flows through the engine, cylinder head, and intake manifold through the water jacket. The coolant absorbs heat from the engine components, leaves the engine when it becomes hot, and enters the radiator again to begin the next cooling cycle.

4. Belt.

Whether it's a timing belt or an accessory drive belt, the belt is usually the link that drives the water pump. Sometimes, a timing chain drives the water pump instead of a belt.

They must always be in good condition and have the proper tension to turn the pump at the correct speed and avoid engine damage due to misalignment of internal engine components.

5. Radiator Cap.

The radiator cap is responsible for maintaining proper cooling system pressure. If the cooling system pressure exceeds the set point, a spring-loaded valve inside the cap releases the excess pressure.

4. Thermostat.

The thermostat regulates the flow of coolant into the engine to keep it at the optimum operating temperature. When the engine is cold, the thermostat closes. Once the engine warms up, the thermostat opens, allowing coolant in the radiator to circulate.

5. Hoses.

Hoses are responsible for moving coolant in and out of the radiator and heater core assembly. If a hose feels spongy or has cracks, it should be replaced.

6. Antifreeze/Coolant

As coolant or antifreeze flows through a hot engine, it absorbs the engine's heat and dissipates it into the radiator.

Most coolants contain rust and corrosion inhibitor additives to prevent deposit buildup and premature damage to cooling system components. Coolant comes in a variety of colors and formulations. Always use the formulation and mixture recommended by your vehicle manufacturer.

7. Fan Clutch.

The fan clutch engages as needed to draw air into the radiator. When air is not needed, it allows the fan to idle, which reduces horsepower loss and improves fuel efficiency. Note: Not all vehicles are equipped with a fan clutch.

8. Antifreeze Plugs.

These are actually steel plugs used to seal holes in the engine block and cylinder head that are created during the casting process. In cold weather, these holes can pop out without adequate antifreeze protection.

9. Cylinder Head Gasket/Timing Cover Gasket.

Seals major engine components. Prevents oil, antifreeze, and cylinder pressure from mixing.

10. Heater Core.

Uses heat released from the antifreeze and blows it into the vehicle through the blower motor to provide heat to the interior of the vehicle. When leaking, it may cause steam, odor or dripping inside the car.

Necessity of cooling system

The cooling system has three important functions. First, it removes excess heat from the engine; second, it maintains the engine at the optimal operating temperature; and finally, it allows the engine to rise to the appropriate operating temperature as quickly as possible.

The reasons why internal combustion engines need a cooling system are as follows:

When the engine is running, the internal temperature can reach up to 2500 degrees Celsius, which exceeds the melting point of the engine components. Therefore, we need to use the cooling system to dissipate heat as much as possible.

As we all know, the normal operation of the engine is inseparable from the lubrication system, but due to high temperature, the properties of the lubricating oil may change, causing the engine to seize. Therefore, in order to avoid this, we need to use a cooling system.

Sometimes due to the huge heat, thermal stress will occur inside the engine, so in order to minimize the stress, we need to reduce the engine temperature as much as possible.