With the design and layout of a car cooling system, all heat absorbed from the engine is stored in the radiator, where the cooling fan blows the heat away. The cooling fan is also known as a radiator fan because it’s mounted directly to the radiator in some engine layouts.
Typically, the fan is positioned between the radiator and the engine as it expels heat into the atmosphere. In front-wheel cars, the battery powers an electrical component that powers the radiator fan.
It’s usually mounted transversely; that is, the output of the engine faces toward the side of the vehicle. In this reading, we’ll explore what a car cooling fan is, its function, diagram, parts, types, and how it works.
Let’s get started!
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What Is A Car Cooling Fan?
A cooling fan is an essential component in a car’s cooling system that helps dissipate the heat absorbed from the engine using coolant. All its work is done through the radiator by pushing or pulling air through the radiator.
A radiator cooling fan is located in front of a car, and it’s electrically powered, well, depending on the vehicle design. A thermostat or an electrical system can activate the cooling fan in modern engines.
The thermostat, which is located between the engine and the radiator, helps to control the working temperature of the engine. The electronic system senses when the coolant in the engine is extremely hot and then powers the fan through an electrical relay switch.
Note that the system is at rest until the engine is excessively hot or the car is stationary. It then powers up when the thermostat gives way to the hot coolant in the radiator. A functional sensor plays a vital role as the cooling fan can sense when to power up.
Functions Of Car Cooling Fan
The car cooling fan’s primary purpose is to assist in cooling the engine and prevent overheating. Here are the main functions of a car cooling fan:
- The cooling fan dissipates excessive heat that the engine has absorbed. Engine coolant absorbs the heat and goes into the radiator, where the heat is blown away.
- The system is functional when the engine is stationary, when air can’t move through the grille.
Cooling fans help to obtain external airflow when moving too slowly. - Electric cooling fans control the temperature of the vehicle as they turn on and off based on the engine temperature.
Diagram Of Cooling Fan In A Car
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Parts of Radiator Cooling Fan
A radiator cooling fan consists of several key components, all working together to keep the engine from overheating by facilitating airflow through the radiator. Here are the main parts of a radiator cooling fan:
Blade Assembly
The blade assembly is a radiator fan’s primary (and most noticeable) component. It typically has arms that connect to a hub. The blades’ job is to force air through the radiator core when the fan is operating. The amount of air moved by the blades is often measured in CFM or cubic feet per minute.
Motor
Only electric radiator fans may use this motor, which is essentially a 12V DC motor. The motor’s function is to rotate the blades, generating airflow. One thing that makes radiator fan motor designs different is the size and shape of the motor. Even though the motor has a unique design, it still has all the standard parts.
Clutch
Only mechanical cooling fans use the clutch. It is typically a device that engages and disengages the fan. There are various methods to accomplish that, and the clutch can be either thermally or non-thermally actuated. Thermal cooling fan clutches are the most common type. To turn on the fan or let it run freely, they rely on a temperature-sensitive device.
Shroud
Nowadays, a lot of radiator cooling fans have a shroud. The metal or plastic shroud encloses the fan assembly. Its primary purpose is to prevent losses and direct air to the radiator. In this manner, the shroud contributes to the cooling fan’s increased efficiency.
The radiator fan shroud can be divided into two pieces or one piece. The fan may come with it or be fitted independently.
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Types of a Car Cooling Fan
The common types of radiator fans are mechanical radiator fans and electrical radiator cooling fans.
Mechanical Radiator Fan
A mechanical radiator fan is an old design of automobile fans but is still used today. It is belt-driven and directly mounted to the engine’s water pump pulley. The power that rotates the cooling fan is obtained from the engine crankshaft, so when it rotates, the fan also rotates.
These types of radiator fans are used in many applications apart from automobiles, as they are less complex and just require mechanical power to rotate them. The mechanical radiator fan is always on as long as the engine is running. Depending on the design, it either pulls or pushes air to cool the coolant in the radiator.
However, fan clutches allow the mechanical cooling fan to go “off and on” when required. That’s according to the temperature of the engine. The two types of mechanical radiator fan clutches are
Viscous-Drive Clutches:
These types of clutches work with a fluid coupling, allowing the fan to engage when the engine reaches a specific temperature. These fan clutches contain a bi-metallic sensor that works like a thermostat. If the engine is cold or at a cold start, the clutch is disengaged, and the fan freewheels. When the engine heats up, the bi-metallic sensor allows the viscous coupling to engage. This causes the pulley to spin along with the fan attached to it.
Electric Fan Clutches:
The engine control unit (ECU) can switch on and off the electric fan clutches, which operate similarly to the viscous types. This gives it more turns up than the first type, as it allows the operation of mechanical cooling to be tightly controlled.
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Electric Cooling Fan
Instead of the engine, an electric radiator fan is a standalone device that draws power from the engine’s electrical system. The system is mounted directly to the radiator for effective cooling and perfectly tightened with bolts and nuts.
These types of radiator cooling fans use a DC motor that switches on and off depending on the engine temperature. Either the engine control unit or a coolant temperature switch is responsible for achieving this. The device can either be mounted at the front or back of the radiator along with the integrated fan shroud.
How A Car Cooling Fan Works
The working of a radiator fan depends on the type of fan. A mechanical fan and an electric fan operate in different ways.
The mechanical radiator fan is mounted to a crankshaft pulley, usually the water pump pulley. When the car is idling or driving at a slow speed, the fan turns on to circulate air through the radiator. In response to an increase in speed, the fan either slows down or stops spinning altogether.
This happens automatically thanks to a clutch’s control. The clutch mechanism functions by enabling the fan to be engaged by the expansion of grease, and vice versa, contingent on engine temperature.
A motor controls the movement of the fan blades of an electric cooling fan. When the engine temperature reaches a predetermined point, the motor starts up automatically and keeps running until the temperature falls below that point.
The engine’s temperature may also affect the fan’s speed settings. A temperature sensor keeps track of the engine’s temperature and sends that information to the radiator fan motor.
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Conclusion
The cooling fan is a crucial component of a vehicle’s engine cooling system, responsible for drawing air through the radiator to help dissipate heat. Whether mechanically driven or electrically operated, the fan ensures that the engine maintains optimal operating temperature, especially during idle or low-speed conditions.
A properly functioning cooling fan prevents overheating, extends engine life, and maintains overall vehicle performance.
FAQs on Cooling Fan
What is the purpose of a car cooling fan?
The cooling fan helps draw air through the radiator to cool the engine coolant, especially when the vehicle is moving slowly or idling.
What are the types of cooling fans?
There are two main types:
- Mechanical fans (belt-driven, often with a clutch)
- Electric fans (controlled by a temperature sensor or ECU)
How do I know if my cooling fan is not working properly?
Common signs include engine overheating, the fan not spinning when the engine is hot, and air conditioning performance dropping during idle.
What causes a cooling fan to stop working?
Possible causes include a blown fuse, faulty temperature sensor, bad fan motor, wiring issues, or a defective relay.
Can I drive my car with a broken cooling fan?
It’s not recommended. Prolonged driving without a working fan can lead to engine overheating and severe damage.
When does the cooling fan turn on?
In most modern cars, electric fans activate when the engine reaches a certain temperature (around 200–230°F or 93–110°C) or when the A/C is turned on.
How can I test if my electric cooling fan is working?
You can run the engine until it heats up and observe the fan. Alternatively, test the fan circuit using a multimeter or connect the fan directly to the battery (with caution).