Radiator Fan Not Working

Radiator Fan Not Working – So What’s The Issue With This?

So, you are going on the road and at a low speed, and you notice how the temperature gauge is slowly climbing up and your car starts to overheat. You probably wonder why is this happening to you? You are sure that everything is in check, and the last thing on your mind is that your radiator fan not working.

This can be a bummer. Fans are there for a purpose, and that is to turn on when there is a reason for it. And that reason is to cool down your radiator. The radiator fan not working may cause your engine to overheat, especially if this happens during a hot summer day.

Summer can be really harsh on cars. The cooling system is saving your car from overheating during the whole summer. The most important piece of the cooling system is the fans. I’m saying this is because, when everything becomes boiling hot in your engine. Your car can’t keep up cooling itself with the drag of warm air. The ECU sees danger when the temperatures are rising, and turns on the radiator fan. This fan will then drive some extra cold air into the radiator. This basically saves your engine and also your wallet.

If your engine overheats, things can get pretty expensive if you are asking me. A new engine can cost thousands of dollars and the install is a plus. So, keep this in mind.

If you are feeling that the radiator fan has stopped working, follow up. Because we have some explaining to do on why this annoyance is happening to you right now. And trust me, there are plenty of reasons why the radiator fan not working.

How This Radiator Fan Works?

The radiator fan works in a simple way. It engages when it sees that the cooling system cannot handle the heat. This heat is usually caused by harsh hot conditions or uphill climbing, causing a big load on the engine. This makes the water pump spin a lot faster and will move the water through the engine very quickly.

And unfortunately, in these situations, there isn’t enough cool air to make the cooling possible. The radiator that is placed up front behind the grill, doesn’t get enough cool air to continue working properly and keep the car at the right temperature. Here the cooling fan comes into place.

The cooling fan spins at high speed, delivering cool air to the radiator in the process. This cool air cools the radiator down and reduces the temperature in the engine. Resulting in better performance and the engine avoids being overheated.

This fan has saved your engine’s life numerous times. If it’s not for this radiator fan, your engine will probably overheat in these types of situations. So, it is a smart idea to keep your radiator in check and always keep track of the temperature gauge. Especially if you are driving uphill and your engine is put on a high load.

If your radiator fan not working, you may get in big trouble and your engine may overheat. So be aware and always remember, if you see that your car is overheating, better come to a stop, and let it cool down for a few minutes. Because you never know what may happen.

What Are The Symptoms Of Radiator Fan Not Working?

Overheating is the only symptom that you will instantly notice. You will see how the temperature gauge starts to climb into the red zone.

This is a clear sign that your fan is not working, or something else is wrong with your cooling system. You need to stop the car if you notice that it starts to overheat.

Don’t touch the coolant cap, because it may splash you with hot coolant and burn your skin. Leave it like that to cool off, and continue driving. After you come home, make an appointment with your local mechanic. Or if you are into mechanical stuff, you can test your radiator fan by yourself. And in the next chapter, we are going to explain how you can perform this check.

How To Check If The Cooling Fan Works Properly?

Crank Up the A/C

A simple way to check if the radiator fan is working is to start your engine and turn the air-conditioning system (A/C) to the maximum speed. If the fan is spinning, then it means that the fan motor, fuse, wiring, and relay are all working properly. The only drawback of this test is that it isn’t showing you, if the temperature coolant sensor, temperature switch, and ECU are powering the fan when the temperatures get boiling hot.

Radiator Fan Not Working

In some cars that run with variable fan speed. The ECU is taking a lot of input from many different sensors when deciding on how fast and how often it should run the fan. If some of these inputs are faulty, they will send the wrong data to the PCM. Then the PCM will give wrong instructions to the fan on when should turn and at what speed.

In this case, you should check your sensors and see if they are working properly. If some of these sensors are failing, you will also going to have a check engine light on your dash. This light means that is time to troubleshoot.

Scan The Car For Codes

Connect your OBD scanner tool into your port and scan the car for possible errors. If these sensors are bad, you will get some errors. The tool is going to tell you precisely which sensors are bad and how to replace them. Usually, two sensors are connected with this issue, the temperature coolant sensor, and the temperature switch.

If you want to check at what temperature the fan turns on. You will need to turn the AC off and run your engine until it reaches a normal working temperature. Most of the fans turn on when the coolant reaches around 200 degrees. In this case, if the fan does not turn on it means that its something wrong with your fan circuit. You should perform resistance checks with an ohmmeter and see if the fan circuit is any good.

Test The Fan Motor

You can also check the fan motor with jumper wires. To perform this task, just unplug the wiring connector that goes to the fan and use the jumper wires that will take juice directly from the battery, and then power up the fan. Here is a video on how you can test out the fan motor. But please don’t do this if you don’t know what you are doing.

If the fan motor is good then it should run at normal speed when you will supply it with 12 volts of power. If the bearings are noisy and some bad sound is heard from the fan, or if the fan runs slow, then this is a clear indicator of a worn-out motor. In this case, you will need to replace the fan assembly with a new one.

Reasons Why The Radiator Fan Not Working

There is plenty of reasons why your radiator isn’t working. We are going to list them all with their proper fixes. And we also are going to give you some troubleshooting bits of advice on how you can get these things done at home on the driveway. Without doing all the work at a mechanics shop and spend a lot of money on labor in the process. So, follow along while we dive into this problem.

Bad Wiring

When troubleshooting this issue, it is important to inspect the wiring that goes to your radiator fan. Be sure that all of the wirings are ok and aren’t messed up.

There are many factors that can ruin your wiring to your radiator fan, like age, heat, rodents. Yes, rodents can eat up your wires and cause some electrical issues like fires in the worst-case scenario. So, if you park your car in a place where are rats or mice, it is a smart idea to check the wires. Also, heat can be a great factor when it comes to wires and can melt them down.

If you want to check your wires, just unplug the electrical connectors for the radiator fan. Check the wires with a voltmeter and see how much electricity they are transmitting. If they are transmitting 12 volts. It means that everything is in proper working order. If there is less, then it means that the wires need to get checked if there is any damage to them and replace them if needed.

If the wires are ok, then you can also inspect the relay. The relay is providing the wires with electricity. This relay knows to die off with age and cause these issues. So, give it a check with the voltmeter as well. If the relay is bad then you need to properly replace it with a new working relay that will feed your radiator fan with electricity with no issues whatsoever.

Broken Thermostat

Thermostats are known to go bad and cause all sorts of cooling issues. They can die all of a sudden. Especially a newly replaced thermostat that you don’t expect to cause you major issues.

The thermostat is an important tool that your car uses to be properly cooled. The thermostat opens and closes when there is a need to. How it works is simple. When the temperatures outside are cold the thermostat stays closed and the coolant stays in the engine. When the coolant reaches the working temperature the thermostat opens and the coolant circulates through the cooling system.

If this thermostat doesn’t open when the engine reaches the working temperature, the coolant will stay inside the engine block and the engine will start to overheat. This will result in the radiator fan not working. The ECU will decide that there is no need to turn on the radiator fan because the thermostat is closed and rad is most likely below the cooling temperature.

After you notice this issue your temperature gauge will probably start to rise and some overheating issues will appear. The engine will start to feel ill and will eventually die. If there is too much heat it may cause cracking of the block, or it may cause the engine heads to warp.

This will happen to you if you do not replace the thermostat when you see an issue. When your engine overheats there is something wrong. Test your radiator fan like we described above and also check if your thermostat opens and closes when it needs to. This will help make you sure, that it’s the thermostat and you can properly replace it.

When it’s time to replace the thermostat, it is a good idea to go for a brand that is proven and will not let you down. You may do this work by yourself or you may take your car to the local mechanic’s shop. If you are into DIY, swapping the thermostat and the water pump by yourself is an easy task.

Broken Fuse

A broken fuse is probably one of the most common reasons why your radiator fan isn’t working as it should. Fuses are created to blow, in order to prevent some catastrophic engine damage caused by a bad electrical installation. Sometimes they blow by accident, you never know what may happen.

In order to check the fuses, open up your hood, and there you will find your fuse box. Find the fuse that is right for the radiator fan. Pull it out and give it a look. If the metal wire inside is still connected it means that the fuse is ok. If the metal inside is burnt, or there isn’t a connection between the two connectors then it’s time to replace the fuse.

Fuses are relatively cheap and you can find them in your local parts store. Replace the fuse with a new one and you are ready to go. Simple as that. If you are still getting a check engine light on the dash, it is time to delete the codes with an OBD scanner tool. If the fuse blows soon after, then it is maybe something else that is causing this issue.

Broken Coolant Temperature Sensor

A broken coolant temperature sensor can also make the radiator fan not work as well. When this sensor fails it may cause overheating in the process. This sensor may also relate to other different symptoms as well. Some of them can be really damaging for your engine like poor fuel economy, black smoke, uneven work of the engine, check engine light.

How this sensor works is pretty simple. The sensor measures the temperature of the coolant and sends this data to the ECU. Then the ECU based on this data decides on what will be the next steps, should it turn the radiator fan on or not?

When this sensor breaks can cause a permanent cold or hot signal. This signal will make your engine think that it doesn’t need extra cooling to be applied from the fans, and it will cause the radiator fan not to turn on when it has to. And this may lead to overheating.

Get An OBD Scanner

How you can fix this is with a diagnosing tool. You will need a proper OBD scanner that reads all the codes and will give you a precise solution on which sensor is the culprit. Some basic tools may not identify this issue at all. So, get a proper scanner.

Connect the scanner to your OBD port and start scanning the car. Find the errors and look for them online. If one of them is the coolant temperature sensor, then you are good to go and replace this sensor. Replacing this sensor is a DIY-friendly job and will not take you more than half an hour. Here is a video on how you can replace this sensor.

Just unbolt the old sensor and bolt the new sensor. Connect the plug and you are good to go. Don’t forget to delete all the error codes after this job.

Coolant Level

Check your coolant level. If you are running your car on low coolant, it may cause the radiator fan to work all the time and fail prematurely. The radiator fan is not meant to work all the time, so keep this in mind.

Fill up your car with coolant and you will be good to go. And always track your coolant level. Make sure that it is always below max and above the minimum.

Broken Fan Clutch Or Fan Belt

Fan clutches and belts are also known to break. These two are important pieces of the puzzle when it comes to cooling. The clutch is connected to the engine and makes the fan work when needed. If the clutch is broken the fan won’t spin. This is usually the case on old V8 pushrod engines. So, if you have one. I think you might want to look at this clutch and its belt and see if they properly work.

Bad Radiator Fan Motor

If nothing works, then it’s time to see if the radiator fan motor is ok and is properly spinning. You can check this by plugging a different power source into your radiator fan.

Unplug the connector that feeds power to the radiator fan and connect it to a battery. If the fan spins, then the fan is ok. If it doesn’t spin, or it spins with a lot of trouble, then the problem is probably the fan motor that is inside.

You can fix this issue by replacing the old radiator fan with a new one and your radiator fan should work properly and turn on when needed.

Can I Drive My Car If The Radiator Fan Isn’t Working?

Yes, you can drive your car. But in order to keep it safe, you shouldn’t run it too hard. Be gentle on the gas pedal. Because your car is not in perfect condition. A little push on the gas may cause the temperature level to climb and possibly overheat the engine. Also, it is not recommended to drive your car uphill if you have a radiator fan not working problem.

Don’t drive your car for too long like this. Make an appointment at your local mechanic in time, or if you are into cars, you can replace it by yourself.

Radiator Fan Replacement Cost

The cost for a radiator fan replacement may vary. Depending on what you are replacing. For example, if you are only replacing the fan that is broken, it may cost you $200 to $400. Also, your mechanic will charge you for the labor. Depending on how many hours are needed to get this job properly done.

If you want to swap the fan by yourself, then you will only pay for the fan. But if your fan is broken it’s probably because of the fan motor. This job will cost a little more money to be done properly. Around $600 to be more exact. Not counting the money needed for the labor. With that money you pay for the mechanic, it adds up quickly! In the end, it may cost you around $900 for the whole job.

But be brave and try something new. Especially simple things like radiators and fans, that can be swapped with no previous mechanical knowledge needed. The only thing you need is a will and a little bit of research online on how the job is done.

Go Aftermarket?

You may also go a step forward and go aftermarket. Especially if you are running an old classic motor. Look for the best solutions and swap your whole cooling system. Systems back in the day were junk compared with new ones. You can get a proper one for less than $600. If you mount it by yourself, even better. But keep in mind to be careful, because these radiators and fans are known to be very prone to damage.


In this article, we discussed everything you need to know when you are having an issue with radiator fan not working. We shared all of the symptoms related to this and their proper fixes.

If you have a radiator fan not working, then it’s time to make an appointment at your mechanic to see what’s the matter with it. You may pay some money but in the long run, you will save even more. Imagine if your engine overheats and blows up? You don’t want that thing to happen to you.

If you run a classic, it is also a good idea to see the aftermarket offering and get a modern cooling system. It will be a lot better than those old systems that were made back in the day.

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