The radiator fan is part of the engine cooling system that functions as a cooler for the AC condenser. The radiator fan also serves to maintain the stability of the radiator water temperature so that it does not get too hot. In addition, the radiator fan also functions to distribute air to the engine so that the engine combustion process becomes optimal. The mechanism of the radiator fan does not rotate all the time. So when does the car radiator fan rotate? To answer that question, let's take a look at the following review.

When Should the Car Radiator Fan Rotate?

Before you know when the car radiator fan should rotate, you need to understand the types of car radiator fans first. Here are the complete types of radiator fans.

1. Radiator fan with fan belt drive

As the name suggests, this type of radiator fan uses the fan belt to drive it. This type of radiator fan will work when the car engine is turned on. When the car engine is just started, the radiator fan will automatically rotate.

2. Radiator fan with motor fan drive

For the second type, this radiator fan is driven with the help of a motor fan or dynamo. For this type, the radiator fan will not work directly when the car engine is just started.

This type of radiator fan has a very close relationship with ECU (Engine Control Unit). Data from the refrigerant pressure sensor and engine coolant temperature will be used by the ECU to determine when the radiator fan should stop or rotate.

The refrigerant pressure sensor functions as a gauge for AC freon pressure in the hose. Meanwhile, the engine coolant temperature functions as a gauge for the radiator water temperature. These sensors will monitor the engine condition and will send data directly to the ECU.

Thus, the ECU will give a command to rotate the radiator fan if there is any change in data. So it can be concluded that the car radiator fan rotates under the following conditions.

Condition of the car AC in the OFF state

When the car AC is off, the ECU will only use data from the engine coolant temperature sensor. The data provided will be processed by the ECU into the radiator water temperature value. When you just start the car engine, the temperature produced is below 95 degrees Celsius.

This temperature will not cause the radiator fan to rotate, because the radiator fan only rotates when the radiator water temperature is above 95 degrees Celsius.

If the radiator water temperature increases, the ECU will send an active command to the relay so that the radiator fan can rotate. The speed of the radiator fan rotation depends on the radiator water temperature.

Read Also: 6 Causes of Car Radiator Fan Not Rotating & Solutions

Condition of the car AC in the ON state

When the car AC is on, both sensors, namely the refrigerant pressure sensor and the engine coolant temperature sensor, will send data to the ECU.

When you turn on the car AC, there will be an increase in refrigerant pressure. In addition, the ECU will also analyze the signals provided by the blower fan. The signals read by the ECU will later be interpreted that the car AC cooling system is working. Thus, the radiator fan will rotate immediately.

After reading the above review, you now know when the car radiator fan should rotate. If the radiator fan keeps rotating, it is certain that there is a problem with the AC condenser, fan control unit, or damage to the engine coolant temperature sensor. Therefore, you need to contact the nearest Daihatsu dealer for proper handling.