Is your engine’s radiator fan not turning on when it’s supposed to cool your engine? Don’t hurry to shop for a replacement radiator fan yet. In this guide, you’ll learn the signs, causes and how to test a radiator fan.
What Is A Radiator Fan?
The radiator fan is a crucial component in the cooling system of heavy machinery, such as excavators, loaders or tractors. It functions to cool the cooling system by transferring excess heat from coolant to the air around your machinery. If it fails, you’re going to run into engine overheating and then costly repairs. Is the Engine Cooling Fan the Same as the Radiator Fan? Click to explore yourself.
Type of Radiator Fans
Knowing the type of fan you have can help you diagnose the problems. There are two main types of radiator fans in heavy equipment and off-road machinery and they operate and break down in different ways.
- Mechanical radiator fans: You can find these fans on older models. These fans are driven by a belt and pulley system and are powered by the engine directly. They run continuously whenever the engine is operating, providing steady airflow.
- Electric radiator fans: The electrical fans are applied in modern equipment and are controlled by a thermostat. They operate only when additional cooling is needed. They offer improved efficiency by adjusting fan speed based on the engine’s temperature, helping optimize fuel use and performance.
Bad Radiator Fan Symptoms and Signs
Here are common signs telling you the radiator fan is failing.
- Overheating at idle or low speeds.
- Radiator fan not turning on when the engine is warm
- Check engine light is on (See why the check engine light is flashing here)
- Visible damage on the fan blade or fan motor
- Unusual noise from the bearing
Why Is Your Radiator Fan Not Working?
There are several reasons why the radiator fan isn’t turning on.
- Bad radiator fan relay: The relay is vulnerable to current and heat. It is easy to get burned and stop working.
- Blown radiator fan fuse: The fuse can blow due to excessive current or short circuits. As a result, the fan won’t receive current and will stop working.
- Bad wires and connectors: When the cables and connectors are broken or corroded, it will cause radiator fan problems.
- Faulty control module, temperature switch and sensors: The electric radiator fan depends on components including the ECU, a temperature switch and a coolant temperature sensor. When they fail, the fn operates abnormally.
- Bad radiator fan motor: The motor can fail when the brushes, bearings or armature coil is worn out or burned.
- Damaged radiator fan belt: The belt transfers motion to the pulley that operates the fan. A broken belt could be the culprit for a bad mechanical fan.
- Worn or damaged fan clutch: A radiator fan clutch can wear out over time or go bad in any other way, leading to several mechanical radiator fan problems, such as freewheeling or continuous engagement.
Step-by-Step Guide to Radiator Fan Troubleshooting
Since there are different reasons accounting for a bad radiator fan, here are steps to determine what’s gone wrong:
- Check the fuse. If the fuse is burnt, replace it with the same size and type. If it burns again, there’s an excessive electrical draw or a short.
- Inspect the fan’s condition. Any visible signs like broken blades, indicate that a replacement is necessary.
- Test the fan motor. Connect the motor directly to 12-volt power with jumper wires to see if the fan spins properly. If it doesn’t, the motor is likely burnt out.
- Check the coolant temperature sensor. A signal from the coolant temperature sensor is what triggers the ECU to turn on the radiator fan, and if it’s faulty, it can prevent the fan from working at all.
- Test the fan relay. Since the relay operates as a switch for the fan’s power, a defective cooling fan relay won’t energize the circuit. You can check it with a multimeter or simply swap it with a known good relay to determine if it works.
- Trace the wiring. A broken, shorted, or corroded wire anywhere in the circuits involved can prevent the fan from working.
How to Test A Radiator Fan?
A bad radiator fan motor is one of the reasons leading to the radiator fan not turning on. As such, testing the motor helps determine whether to repair or replace the radiator fan. There are two simple ways to test your radiator fan.
Steps for Testing with Battery
- Locate the fan next to the radiator
- Unplug the connector
- Use jumper wires to power the motor
- Connect the wires to the positive and negative terminals of the battery
- Watch for the motor
If the motor spins, it’s in good condition. And the problem is either a blown fuse or a bad relay. I could also be a loose connector or broken frayed wires. If the radiator fan motor is the culprit, you must replace it with a high-quality radiator motor. It is recommended to replace the whole radiator fan assembly.
Steps for Testing with A Multimeter
- Locate the fan near the radiator
- Remove the fan motor connector
- Identify the terminals that supply current to the motor
- Set the multimeter to read volts by moving the rotary switch
- Connect the multimeter probes to the terminals on the connector
- Check the multimeter
If the multimeter reads around 12 Volts but the fan is not working, you have a burned-out motor. If there’s no voltage, the wiring system is to blame. Consider checking the fuse, relay, wires and connectors.
Frequently Asked Questions about Radiator Fan
Can I drive with a radiator fan not working?
It is not recommended to drive with a radiator fan not turning, especially under heavy loads and in hot conditions. It can cause engine overheating and costly repairs.
Will A/C work fine if the radiator fan fails?
Yes. The A/C still works if you get a bad radiator fan, but it may lead to engine overheating at low speeds or idling.
Should you test the radiator fan with a multimeter?
Yes, a multimeter is an excellent tool for troubleshooting a radiator fan, but it’s primarily used to check if power, ground, and signal are reaching the fan. If you need to check the current as much as the fan, it is a waste of time in most cases. And if you use your multimeter in series with the fan, you’ll blow the fuse in your meter, so it’s not recommended.
Wrapping up
A failing radiator fan means engine overheating is only a matter of time. Troubleshooting is straightforward: start with a quick check for visible damage or blow, check the fuse, move to the relay, then test the motor directly with a battery. If the motor doesn’t spin, it’s time for a full fan assembly replacement. Whether you need a mechanical or electric radiator fan, FridayParts has you covered. We also provide a vast selection of radiator blades, radiator fan clutches, and radiator fan motors. Shop high-quality radiator fans for your machinery and save today!
