The radiator fan (or fans) pulls cooling air through the car’s radiator. Positioned between the radiator and engine, cooling fans are particularly helpful when the car is stationary or moving at speeds too slow to force air through the grille.
The advent of electric cooling fans, which turn on and off as needed, proved an improvement over engine-driven fans that slow down exactly when they’re needed most.
A failed cooling fan can result in an engine overheating. These fans sometimes double as a cooling source for the cabin air conditioning’s condenser.
Today we’ll be looking at the definition, functions, components, diagram, types, working principle, as well as the symptoms of bad radiator cooling fan.
What is a radiator fan?
A cooling fan is a vital component in a car cooling system, that helps takes away all 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.
In modern engines, the cooling fan is activated by two means, which can either be the thermostat or an electrical system.
The thermostat which is located between the engine and radiator help to control the working temperature of the engine. The electronic system senses when the coolant in the engine is extremely hot, and then power 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 for the hot coolant into the radiator. A functional sensor plays a vital role as the cooling fan can senses when to power up.
Functions of radiator cooling fan
Below are the major functions of radiator cooling fan:
- The primary function of a radiator cooling fan is to take away excessive heat absorbed from the engine. The coolant absorbs the heat and goes into the radiator where the heat is blown away.
- The system is functional when the engine is stationary, where air can’t move through the grille.
- Cooling fans help to obtain external airflow when moving too slow.
- Electric cooling fans control the temperature of the vehicle as it turns on and off based on the engine temperature.
Components of radiator cooling fan
In this article, we are explaining both electrical and mechanical cooling fan. As earlier mentioned, the mechanical cooling fan is found on older vehicles, while electrical fans are found on new vehicles.
The components of the mechanical cooling fan are just a cooling fin mounted on the engine, powered by the engine crankshaft. Though it’s mounted on a machined cup with bolts. This cup is allowed to rotate with the engine pump and it serve as a pulley to the drive belt that powers other essential components of the vehicle
The electrical radiator cooling fan is a standalone device with various parts. The parts include a cooling fan shroud, motor, and cooling fan or fan.
The cooling fan shroud serves carriage because the other parts are mounted to it and it’s placed directed to the radiator. Other components will be explained in the working principle section of the radiator cooling fan.
Types of automobile cooling fan
Below are the types of radiator cooling used in automobile engine:
Mechanical radiator fans:
A mechanical radiator fan is an old design of automobile fans but still used today. It’s mounted directly to the water pump pulley on the engine and is driven by a belt. 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 far as the engine is running. Depending on the design, it either pulls or pushes air to cools 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 cooling 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 thermostats.
If the engine is cold or at cold starting, 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 electric fan clutches work similarly to the vicious types, but they can be switched on and off by the engine control unit (ECU) depending on the current engine condition.
This gives it more turns up than the first type as it allows the operation of a mechanical cooling to be tightly controlled.
Electric radiator cooling fan
An electric cooling fan is a standalone device that is powered by the engine’s electrical system rather than the engine. the system is mounted directly to the radiator for effective cooling, perfectly tighten with bolt and nut.
These types of radiator cooling fans use a DC motor that switches on and off depending on the engine temperature. This is achieved either by the engine control unit or by a coolant temperature switch.
The device can either be mounted at the front or back of the radiator along with the integrated fan shroud.
Radiator Fan Function: How does a Radiator Fan Work?
The radiator fan purpose is to blow air through the radiator and remove heat from the coolant. The engine produces a lot of heat, which must be removed to prevent damage. Most engines have coolant circulating and transferring the heat to the radiator. Inside the radiator, the coolant loses the heat to air.
The air to cool the radiator comes from outside and flows freely through the grille. However, that happens when the vehicle speed is above 25 mph. Less than that, and the airflow reduces dramatically.
That’s where the radiator fan comes in. It helps to provide airflow during times when your car is moving too slowly or when the engine is idling.
How a radiator fan works depends on the type. An electric fan works differently from the mechanical type. To help you understand the operation of both, we will look at their working separately.
Mechanical Radiator fan- a mechanical cooling fan mounts on a crankshaft pulley, most often the water pump pulley. During times when the vehicle is idling or moving at a low speed, the fan comes on to blow air through the radiator.
When the speed increases, the fan stops spinning or spins at a lower speed. This happens automatically through the control provided by a clutch. The clutch mechanism works by allowing the expansion of grease to engage the fan and vice versa, based on the engine temperature.
Electric Radiator Fan- an electric cooling fan functions differently. It doesn’t need a clutch, since its switching on and off can be electrically controlled. The fan receives power through a complex wiring system consisting of relay(s), fuse, and cables.
For automatic on and off, electric fans use a temperature switch and coolant temperature sensor. These sensors send signals to the car computer, which then determines when the fan comes on and when it goes off. Modern electric cooling fans come with a dedicated ECU or control module.
An engine cooling fan also operates by either pushing or pulling air through the radiator. Pusher cooling fans are mounted between the radiator and grille. These are less efficient. Puller cooling fans are situated in the space between the radiator and engine. They are more effective and provide better cooling performance.
Symptoms of a bad or failing cooling/radiator fan
Below are the signs of bad and failing cooling radiator fan in automobile engine:
The cooling fan will not come on:
The common and obvious symptom is when the cooling fan not working when the engine ignition is on. This problem often occurs from the fan’s motor or the electrical connection of the system.
When this happens, overheating takes place as the hot coolant will not be properly cooled. Drivers often notice this issue when they did not hear the component sound when the car ignition is on.
Blown fuse:
Most vehicle electrical components work with circuit fuse which cooling fan is among. If this fuse has blown or burned, the cooling fan motor stop working, which is one of the common ways that disconnect the device.
Sometimes, failing or surging of the motor will cause the fuse to blow so that other components will be prevented from damage. The fuse must be replaced to bring the cooling fan back to life.
Vehicle overheating:
This is another common sign of a faulty radiator cooling fan; the engine begins to overheat since the source cooling is down. This also occurs when the cooling fan motor burns out or the fan is disabled.
The motor is what spins the blades to push or pull air through the radiator. So, if the motor fails or weak the blade will not spin or generate enough air to cool the hot coolant.
In modern vehicles, cooling fans are designed with thermostats that come on and off depending on the engine temperature. Thus, once a certain temperature is reached, the fan is supposed to start working.
If it refuses to work, the engine temperature will continue to increase until the engine overheats.
In conclusion, a radiator cooling fan is essential in an engine cooling system, else the radiator would have been useless.
But, with the efficient cooling of the fan, the circulation of coolant is ensured. in this article, we’ve seen the definition, function, as well as components of automobile cooling fan. We also saw, the types, working and symptoms of bad or failing cooling fan.