Engine cooling system: how it works and main components

The engine in your car works best at a high temperature. When the engine is cold, components wear out easily, emits more pollutants, and the engine becomes less efficient. Thus, another important task of the cooling system is to allow the engine to warm up as quickly as possible, and then to maintain a constant engine temperature. The main function of a cooling system is to ensure that the engine runs at its optimum operating temperature. If the cooling system or any part of it fails, it will overheat the engine, which can lead to many serious issues.

Please visit our website for more information on this topic.

Have you ever imagined what would happen if your engine cooling system did not work properly? Overheating can cause cylinder head gaskets to explode and even crack engine blocks if the problem is serious enough. And all this heat must be fought. If the heat cannot be removed from the engine, the pistons are literally welded to the inside of the cylinders. Then you just must throw the engine away and buy a new one. So, you should take care of your engine cooling system and learn how it works.

Components of a cooling system

Radiator

The radiator acts as a heat exchanger for the engine. It is usually made of aluminum and has many small diameter pipes with fins attached to them. Furthermore, it exchanges the heat of the hot water coming from the engine with the ambient air. It also has a drainage plug, an inlet port, a sealed cover, and an outlet port.

Water pump

When the coolant cools after being in the radiator, the water pump sends the fluid back to the cylinder block, heater core, and cylinder head. Eventually, the liquid enters the radiator again, where it cools down again.

Read more about water pumps here.

Thermostat

It is a thermostat that acts as a valve for the coolant and only allows it to pass through the radiator when a certain temperature has been exceeded. The thermostat contains paraffin wax, which expands at a certain temperature and opens at that temperature. The cooling system uses a thermostat to regulate the normal operating temperature of the internal combustion engine. When the engine reaches standard operating temperature, the thermostat is triggered. Then the coolant can enter the radiator.

Read more about thermostats here.

Other components

Freeze Plugs: This is actually a steel plug designed to seal openings in the cylinder block and cylinder heads created during the casting process. In frosty weather, they can pop out if there is no frost protection.

Timing head/cover gasket: Seals major engine parts. Prevents mixing of oil, antifreeze, and cylinder pressure.

Radiator overflow tank: This is a plastic tank that is usually installed next to the radiator and has an inlet connected to the radiator and one overflow hole. This is the same tank that you pour water into before driving.

Hoses: A series of rubber hoses connect the radiator to the engine through which the coolant flows. These hoses can also start leaking after years of use.

Read more: The importance of an automotive thermostat in a car’s cooling system

How does the cooling system work in a car?

To explain how a cooling system works, you must first explain what it does. It’s very simple – the car’s cooling system cools the engine. But cooling this engine can seem like a gigantic task, especially when you consider how much heat a car engine generates. Think about it. The engine of a small car traveling on a highway at 50 miles per hour will generate approximately 4,000 explosions per minute.

Along with all the friction from moving parts, this is a lot of heat that needs to be concentrated in one place. Without an efficient cooling system, the engine will heat up and stop running within minutes. A modern cooling system should ensure the coolness of the car at an ambient temperature of 115 degrees, as well as warmth in the winter weather.

What Happens Inside? 

The cooling system works by constantly passing coolant through channels in the engine block. Coolant, driven by a water pump, is pushed through the cylinder block. As the solution passes through these channels, it absorbs heat from the engine.

Leaving the engine, this heated fluid enters the radiator, where it is cooled by the air flow entering through the car’s radiator grill. The fluid will cool as it passes through the radiator, returning to the engine again to pick up more engine heat and carry it away.

There is a thermostat between the radiator and engine. Depending on the temperature, the thermostat regulates what happens to the liquid. If the fluid temperature drops below a certain level, the solution bypasses the radiator and is instead directed back to the engine block. The coolant will continue to circulate until it reaches a certain temperature and opens the valve on the thermostat, allowing it to pass through the radiator again for cooling.

It seems that due to the very high engine temperature, the coolant can easily reach its boiling point. However, the system is under pressure to prevent this from happening. When the system is under pressure, it is much more difficult for the coolant to reach its boiling point. Occasionally, however, pressure builds up and must be relieved before it can deflate the hose or gasket. The radiator cap relieves excess pressure and fluid by accumulating in the reserve tank. After the liquid in the storage tank has cooled to an acceptable temperature, it is returned to the cooling system for re-circulation.

Keep reading: How to detect cooling circuit problems

Dolz, quality thermostats and water pumps for a good cooling system

Fire has been a pivotal discovery in human history, providing numerous benefits, including in transportation. While the shift towards electric vehicles is gaining momentum, combustion engines still dominate the roads today.

Combustion engines convert fuel into heat energy, which is partly transformed into mechanical energy. The resulting heat must be managed effectively, and this responsibility falls to the vehicle's cooling system. A well-functioning cooling system comprises several critical components, each playing a vital role in maintaining optimal engine temperatures.

Types of Automotive Cooling Systems

Automotive cooling systems can be categorized into two primary types: air-cooled and water-cooled systems. Air-cooled systems are rare and typically found in older models like certain Porsche engines and classic Beetles. Consequently, this guide will primarily address water-cooled systems, which are more prevalent today.

If you want to learn more, please visit our website OKAYPARTS.

Water-cooled systems can be further classified into four types: pump circulation, pressurized cooling systems, thermosyphon, and impeller thermosyphon systems.

Thermosyphon Cooling System

Despite the complex name, the thermosyphon cooling system operates on a straightforward principle. It utilizes the natural convection caused by temperature differences between hot and cold water, allowing circulation without a pump.

This simplicity, however, comes with limitations. Water circulation only begins when the engine heats the coolant sufficiently. Additionally, this system is less effective under high-temperature and heavy-load conditions, which is why it's mostly found in older vehicles.

Impeller Thermosyphon Cooling System

The impeller thermosyphon system enhances the basic thermosyphon design by incorporating an impeller to improve cooling efficiency. While its operation remains similar to that of the thermosyphon system, the impeller assists in enhancing coolant movement.

Pump Circulation System

In contrast to the previous systems, the pump circulation system represents a more contemporary approach. This system employs a centrifugal pump powered by the engine to maintain coolant flow throughout the system.

Pressurized Cooling System

The pressurized cooling system is a significant advancement over its predecessors and is widely adopted in modern vehicles. It features a radiator cap equipped with a spring-loaded pressure valve, which raises the boiling point of the coolant, allowing for improved thermal efficiency.

This system is designed to maintain consistent pressure within the cooling system, aided by a water pump that facilitates circulation.

To fully grasp the functionality of a pressurized cooling system, it's essential to understand its individual components. Below is a diagram illustrating the main parts of a modern engine cooling system.

Modern Cooling System Diagram

Radiator

The radiator serves as a critical component of the cooling system, responsible for lowering the temperature of the high-heat coolant exiting the engine. It consists of three parts: an upper tank, a lower tank, and a core. The coolant first enters the upper tank, flows through the core (where copper fins help dissipate heat), and finally exits through the lower tank to return to the engine.

Water Pump

The water pump, typically a centrifugal unit, is mounted at the front of the engine and is driven by a belt. It comprises various smaller components that work together to ensure efficient coolant circulation throughout the system.

Radiator Fan

The radiator fan is either directly connected to the crankshaft or operates independently as an electric unit. Its primary roles include drawing fresh air through the radiator for enhanced cooling and assisting with engine cooling.

Thermostat

The thermostat regulates the engine temperature by opening and closing based on coolant temperature. It keeps the valve closed during the warm-up phase, allowing the engine to reach its optimal operating temperature swiftly.

Heater Core

The heater core acts as a small radiator located beneath the dashboard, transferring heat from the engine's coolant to the cabin. This process increases cabin temperature when needed.

Cooling System Maintenance

Flushing

Consult your vehicle’s owner’s manual for recommended coolant flush intervals. Perform a thorough flush using appropriate equipment, ensuring to refill with the correct type of coolant and remove any trapped air from the system.

Periodic Check-ups

Routine inspections of the cooling system components are vital. Monitor the coolant level in the reservoir, checking for discoloration that may indicate rust. Inspect rubber hoses for signs of cracking.

Common Failure Points

Rusty Radiator

Over time, radiators can develop cracks, particularly at the inlet or outlet ports, leading to coolant leaks and potential engine overheating. These ports, often made of plastic, can become brittle and fail.

Hardened Hoses

Cooling system hoses, while often overlooked, play a vital role. Made of rubber, they can become hard and develop cracks with age, leading to coolant leaks that may escalate into more serious issues.

Thermostat Failure

A malfunctioning thermostat can become stuck open, causing the engine to run cooler than necessary, or stuck closed, resulting in overheating. Regular checks can help avoid costly repairs.

Water Pump Failure

Water pump issues can arise from various causes, including improper installation of the mechanical seal, low coolant levels, or incorrect belt installation. Each of these can lead to significant cooling system failures.

We Have Everything for Your Cooling System!

From radiators to pumps, we provide high-quality OEM parts to address all your cooling system needs. Explore our Shop section for a comprehensive selection of components for a wide array of vehicles.

About Newparts.com

Whether you're repairing your vehicle, performing preventative maintenance, or upgrading performance, Newparts.com is your trusted online source. With over 15 years in the business and more than 20 million auto parts shipped, we're here to help you keep your car running right. From top-tier brands to exclusive Kits That Fix, our goal is to simplify your repair process and save you money.

Contact us to discuss your requirements of OEM Engine Cooling System. Our experienced sales team can help you identify the options that best suit your needs.

Why Shop at Newparts.com?

• Trusted by DIYers and Pros: Over 15 years of dependable service to car enthusiasts and mechanics alike.
• 20+ Million Parts Shipped: Proven fulfillment capabilities backed by real experience.
• Top Brands at Great Prices: We offer premium brands at some of the lowest prices online.
• Exclusive Kits That Fix: Complete, curated repair kits that eliminate guesswork.
• Fast Shipping: Reliable delivery from our U.S.-based warehouses.