Fanned Radiator: When Does the Car Radiator Fan Rotate? This is the Explanation

When does the car radiator fan rotate? What conditions cause the fan to turn on continuously? Here are 6 causes that should not be ignored

Fanned Radiator When Does the Car Radiator Fan Turn This is the Explanation


Have you ever wondered when the car radiator fan rotates? Or why the car radiator fan keeps turning on? Of course, these two conditions indicate that there is a problem in the car. In addition, the radiator is very important for cooling the engine. Driving also becomes uncomfortable. So, let's first find out when the car's radiator fan rotates.

Function and operation of the radiator fan

Before knowing when the car radiator fan rotates, need to know the function of the radiator fan and how it works. The main function of the radiator fan is to keep the cooling water at a temperature corresponding to that of the engine during operation. In addition, the radiator fan also serves to cool the temperature of the air conditioning condenser to keep it in normal condition.

There are two modes of operation, which are distinguished by the operation of the fan:

  • Manual fan

The crankshaft-driven radiator fan or manual fan moves continuously when the engine is started. This cooling fan is connected to the crankshaft by a pulley and belt (V-belt).

The resulting rotational speed will depend on the speed of the rotating motor. If the motor is rotating at high speed, the fan will also rotate faster.

  • Electric fan

This radiator fan driven by an electric motor no longer uses the rotation of the motor shaft to turn the cooling fan. However, the electric motor can move or rotate if an electric current flows through it. The type of electric motor used to drive the radiator fan is a DC electric motor.

Causes of the radiator fan continuing to turn

Starting from the electrical components, such as the ECU and air conditioning, to the fan belt component, it can cause the car radiator fan to turn on continuously. Here is the discussion:

1. The water temperature sensor is damaged

The first common cause is damage to the water temperature sensor (WTS). The WTS is also often referred to as the ECT (Engine Coolant Temperature Sensor). This damage usually occurs due to a short circuit. The resistance value of the WTS will remain at 0 and electric current will continue to flow to the ECU.

The ECT is heat sensitive and reacts according to the temperature of the object being measured. Then, data from the sensor is sent to the ECU. In the ECU, the data is translated to estimate the engine temperature. For example, the engine temperature has reached 90 degrees Celsius. 

This means that the ECU should turn on the radiator fan at a low speed until the temperature reaches 80 degrees. Only then will the fan turn off. If the temperature does not drop or even rise, the control unit will speed up the rotation of the radiator fan. Therefore, if this sensor is damaged, the radiator fan will continue to run.

2. Damage to the coolant pressure sensor

Besides the WTS, a component that could be damaged and keep the radiator fan running is the coolant pressure sensor. If this component is damaged, the fan will continue to turn on even when the AC is on.

Normally, when the AC is not on, the fan rotation will remain normal according to the condition of the engine cooling system. However, if the coolant pressure sensor component is damaged, the ECU commands the radiator fan to keep turning.

3. Damage to the AC condenser.

The rotation of the car radiator fan is still related to the car air conditioner. This AC system is equipped with a capacitor. The function of the condenser is to cool the refrigerant or freon. What does it have to do with the radiator fan? This is because the condenser is located in front of the radiator. So in addition to cooling the radiator, the fan also cools the freon inside the condenser.

Sometimes, when the AC is on, the radiator fan does not cool the radiator, but the condenser. However, this does not mean that the fan runs as long as the AC is on. The fan runs only when the temperature is above 90 degrees.

So if the radiator fan keeps turning on when the AC is turned on, there may be a problem. It could be an electrical problem or a blockage of freon circulation.

4. Malfunction of the fan control unit.

The next cause of the radiator fan spinning is the problem with the fan control unit. The function of this component is to adjust the rotation speed of the radiator fan according to the needs of the engine. However, many modern cars do not use this component. 

5. Damage to the radiator fan relay

Damage to the radiator fan relay may also be the cause of the time when the car's radiator fan rotates continuously. This component is an electrical switch that works electromagnetically based on the current entering the coil. This means that if a short circuit occurs in this component, the radiator fan will continue to turn on. Generally, the cause of damage to the radiator fan relay is the age of use.

6. Visco fan is damaged

Another cause may be damage to the Visco fan. What is a Visco fan? A Visco fan is a fan that uses oil as a speed controller. It works according to the rotation of the motor. If the motor is at a low temperature, the Visco fan will slip and rotate slowly. And vice versa. If the Visco fan is damaged, the rotation of the fan also becomes erratic.

These are the 6 situations in which the car radiator fan rotates and the causes of the radiator fan turning on continuously. When there is a problem with the radiator fan, the first thing to check is the non-electrical one. 

If there is an electrical problem with the engine, the check engine light will usually come on. The way to check this is to use a scan tool at the nearest repair shop.

Next, we will discuss the effects of a continuously running radiator fan.

Effects of continuous operation of the radiator fan

The car's radiator fan is constantly on, which can cause several effects. It is also not advisable to allow this condition because of the following effects:

1. The battery is quickly discharged

The constantly on and uncontrolled radiator fan causes the battery to discharge rapidly. As a result, the car's electrical system cannot work perfectly and the trip becomes a bit disturbed.

2. More wasteful engine 

In addition to battery problems, the car's fuel consumption will also be wasteful. The car seems less powerful because the engine will continue to work, resulting in more fuel consumption. An engine that continues to work inefficiently will make the drive less strong.

3. Driving comfort is compromised

The radiator fan running continuously surely causes anxiety and discomfort in driving, right? Therefore, you need to overcome it immediately so that driving is comfortable again.

Have you responded when the car radiator fan rotates? If you find a problem with the radiator, you should immediately check it at the nearest workshop. This is especially true for cars that use an electronic control unit. Find the nearest workshop that has a scan tool.

See also what are the most important parts in a car


FAQ

What is the function of the radiator fan?

The main function of the radiator fan is to keep the cooling water at a temperature corresponding to that of the engine during operation. In addition, the radiator fan also serves to cool the temperature of the air conditioning condenser to keep it in normal condition.

Why does the car radiator fan keep running?

Starting from the electrical components, such as the ECU and air conditioning, to the fan belt component, it can cause the car radiator fan to turn on continuously.

What happens if the radiator fan keeps turning on?

Several effects can be felt when the car radiator fan is continuously turned on, namely:

The battery is quickly discharged

The engine is more wasteful

Driving comfort is affected


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