Symptoms of a Bad Radiator Fan and Checking Process

Virtually, the vast majority of road-going vehicles and all late model cars are equipped with radiator fans that help to maintain optimum operating temperature. They’re located close to the radiator to help cool the engine and radiator by pulling air through the radiator fins, especially during low speed or idle, where there is little or no air to pass through the radiator fins. The cooling fan helps the radiator maintain the right operating temperature by providing airflow to the engine and radiator.

Cooling fans have similar electric motors to regular industrial use electric motors. The radiator cooling fans are often replaceable and serviceable components of the cooling system, making them easy to replace when they fail.  When the radiator fan spins, it generates air. Suppose they eventually fail; they will affect other engine components. To prevent engine overheating, you should be on the lookout for Symptoms of a Bad Radiator Fan and know how to check if the radiator is working.

what happens if your radiator fan stops working

What are the signs and symptoms of a bad radiator fan?

Just like every other issue that occurs in a vehicle, there are a few symptoms that indicate a lousy radiator cooling fan. Hence, if you notice any of these symptoms, you have to inspect or call for professional assistance to thoroughly inspect your radiator fan.

1. fan not coming on

The most common bad cooling fan relay symptom is that the cooling fan will not come on. If the electric motor fails or burns out, which is usually the case, the fan will not work. This is because the electric fan motor works together in harmony with the fan blades to pull air through the radiator fins.

2. Blown radiator fan fuse

A blown radiator circuit fuse is another symptom of a failing or lousy radiator fan. If the electric motor surges or fails, it will blow the cooling fan circuit fuse to keep the rest of the system safe from any electrical surge. The blown fuse will have to be changed for the radiator fan to start working.

3. Temperature warning light

The temperature warning light indicates a problem in the cooling system. Whether or not you’re driving and this pops up on your dashboard, you have to shut off the car and allow it to cool to prevent overheating. Chances are, the temperature warning light pops up because you have a failing or lousy radiator fan.

4. Poor A/C performance

If you notice the radiator fan not working when AC is on, you should seek professional advice. A lousy radiator fan can create car air-conditioning (AC) issues. This is because the radiator cooling fan creates double the amount of air that the condenser fan. The radiator fan pulls air through the condenser, which removes the heat vapor of the refrigerant inside. If the radiator fan fails, it will affect the AC performance.

5. Vehicle Overheating

Engine overheating, a typical bad radiator symptom, occurs whenever there is a problem with the cooling system. Electric radiator fans are designed to come on once certain conditions are met or a specific temperature is reached. If the radiator fan fails, the engine temperature will continue to rise until the engine overheat. Since engine overheating is a common problem with the cooling system and can be caused by various problems, you have to diagnose or contact a professional mechanic to track down the cause of the overheating.

6. A loud whirring Noise

In some cases, when the radiator cooling fan motor fails, you’ll notice a loud clicking or whirring noise that changes as you rev your engine. The radiator cooling fan is sensitive and works together in harmony with the blades, and if one of them goes out of place, it might come in contact with other components and vibrates. When the fan clutch begins to fail, it will cause an embarrassing whirring noise. Bad radiator fan noise might be so loud, but fixing it on time will save you from the expensive repair costs.

How do you check a radiator fan?

How to check a radiator cooling fan depends on a manual or electric fan. To test an electric fan, start your engine and allow it to reach the average operating temperature, where it usually comes on, grab your voltmeter and check if the voltage is getting to the wires. If the voltmeter reads close or up to 12 volts, power is getting to it. If it doesn’t, you probably have a lousy cooling fan. Also, you can better understand by watching this YouTube Video. 


Q: What happens when a radiator fan stops working?

What happens when a radiator fan stops working? It will cause a loud whirring noise and a stuck open thermostat (which will not allow the engine to reach the average operating temperature). A lousy radiator cooling fan could cause a blown circuit fuse, a malfunctioning relay, and engine overheating.

Q: Can you drive with a bad radiator fan?

Yes, if your radiator cooling fan fails, you can drive with it. Technically, your vehicle engine does not need a radiator fan to operate. However, if your vehicle engine does not receive enough air blowing it constantly, it will eventually lead to overheating. So, you don’t have to drive a long distance with a lousy radiator fan to avoid overheating.

Q: What does a bad radiator fan sound like?

Every car has a kind of noise they make. After driving your vehicle for a long, you should know how your vehicle sounds and be able to detect when something is out of place. In some cases, when your radiator cooling fan clutch fails, it will develop a whirring or clicking noise. The noise could result from a bearing that is out of place or a bent fan blade that is touching other components.

Q: When should a radiator fan come on?

Mechanical radiator cooling fans will come on immediately after you start your engine. On the flip side, the electric radiator cooling fan will only turn on when the car engine reaches a certain temperature. However, if your car is equipped with an electric radiator cooling fan, it should come on at about 200 degrees Fahrenheit. If you notice your engine is running hot or overheating, you have to check if your radiator fan is blowing.

Final Words

As the radiator cooling fan is a vital component of the cooling system, it is essential in maintaining the engine’s optimum operating temperature. When it starts failing or eventually goes bad, the car engine will start overheating. If you notice your engine is showcasing any of the symptoms of the bad radiator fan above, ensure you contact a professional mechanic to inspect and fix the problem.

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Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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