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How Do I Know If My Radiator Fan Is Bad?

CarPart  ·  March 30, 2023

How Do I Know If My Radiator Fan Is Bad?

An essential type of part you'll find in all vehicles are cooling fans. Of course, you're likely familiar with the ones inside the cabin that keep you and your passengers comfortable. But there's a radiator fan under the hood that also keeps your engine cool.

You'll know the radiator fan is bad when it fails to turn on. Besides that, loud noises and visible damage signs can indicate the fan isn't functioning correctly. Other signs include a warm air conditioner, an overheating engine, and loud knocking or grinding noises from your car's front.

The radiator fan is a simple component, but you should never take it for granted. Read this guide to understand how it protects your engine and what signs to look for when the fan goes bad.

What Does a Radiator Fan Do?

The radiator fan is an incredibly straightforward component with one clear purpose: to drive air through the radiator. The fan helps your car’s cooling system dump heat more effectively to keep the engine within safe operating temperatures.

The radiator fan doesn’t stay on all the time. Instead, it depends on the coolant temperature that flows through the radiator.

Remember: the cooling system circulates coolant, which absorbs heat from the engine. Then, the coolant flows through the radiator so the passing air can remove its heat. From there, the now-cool coolant continues flowing to repeat the process.

Air will naturally blow through the radiator when you’re driving. However, natural airflow is often insufficient, especially when your car is moving too slowly or has come to a halt. 

The same is true if you’re driving your car in sweltering climates where the natural air isn’t cool enough to remove heat from the radiator efficiently.

That’s why the radiator fan is a necessity. When the cooling system senses the coolant reaching high levels, it switches the fan on to drive more air through the radiator and keep everything cool.

As you can imagine, the radiator fan is critical in stopping your engine from overheating and damaging itself.

How Do I Know If My Radiator Fan Is Bad?

Given how critical the radiator fan is to your engine and other vital components, you must understand the signs of a fan that’s going bad.

Here are a few of the most important symptoms to pay attention to:

1. Never Turns On

Earlier, you read that the radiator fan doesn’t stay on all the time. Instead, it alternately turns on and off depending on the cooling system’s temperature. 

You'll know the fan is problematic when it doesn't turn on.

For example, the radiator fan should turn on if you’ve had the engine running for several minutes. When that doesn’t happen, there’s an issue with the fan or motor.

2. Engine Overheating

Another clear sign that the radiator fan has failed is the engine overheating. Of course, you must first rule out all other possibilities with the vehicle’s cooling system.

Suppose the system is functioning correctly, free from leaks or clogs, and has sufficient coolant inside, then in that case, the most likely culprit is a failed radiator fan.

3. Warm Air Conditioner

The radiator fan doesn’t always fail completely and straight away. Instead, it can gradually fail and functioning intermittently. When that happens, you’ll notice more subtle signs like the air conditioner temporarily blowing warm air.

If you’ve driven your car long enough, you’ll be familiar with how your air conditioner feels.

So, if it feels suspiciously warm, even briefly, it’s best to diagnose the radiator fan immediately. Even if it hasn’t failed completely, it might be at the end of its lifespan.

4. Loud Noises

Like any other fan, the one for your radiator consists of spinning fan blades and a motor. So, there are times when the fan can go bad and start creating loud and unusual noises.

For example, a damaged fan blade could cause a repetitive knocking sound from under the hood, close to the vehicle’s front.

Meanwhile, a faulty fan motor could cause grinding or screeching noises from the same place.

When you notice any of these sounds, it’s best to inspect the radiator fan for any issues.

If your engine is running, keep your fingers away from the fan blades! You never know when the fan might turn on.

5. Physical Damage

The final sign that your radiator fan has gone bad is the physical damage you can see on the fan itself. As you read earlier, the damage could be with the fan blades or motor, so inspect both parts.

For example, the fan blades could be bent or broken, or you might find marks on the motor or assembly showing a rock or hard object stuck there.

Can I Drive My Car If the Radiator Fan Is Bad?

If your radiator fan is not working, you must not drive your car or start the engine.

Sure, the engine will crank and start without a problem. However, that engine will overheat quickly if the radiator fan isn’t functioning correctly.

Attempting to drive a car in that situation isn’t only risky but also foolish. You shouldn’t even drive it to your mechanic because the engine will likely overheat and damage various components under the hood. Instead, you should call the workshop and find a towing service to take your car to them. 

Are Aftermarket Radiator Fans Better Than OEM?

When shopping for replacement parts, you may be tempted to go with an aftermarket radiator fan, and there’s nothing wrong with that. Like any other commodity, there are good as well as bad aftermarket parts.

The market is full of cheap radiator fans you can purchase, but you can’t be 100% sure about their reliability. At the same time, you can undoubtedly find high-quality and durable aftermarket fans if you exercise due diligence.

Choose one from a reputable brand, preferably with plenty of positive reviews you can base your decision on.

If you want to save money, don't forget that you can also buy used radiator fans and parts. One place you can shop for those parts is the CarpartAU marketplace.


By Ray Hasbollah

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