radiator fan

5 Reasons Why Your Radiator Fan Is Not Coming On

In Electric by Magnus Sellén15 Comments

radiator fanThe engine of a vehicle has a combustion chamber where continuous explosions take place and as such the engine heats up very quickly.

To stop the engine from overheating, we take the help of coolants that flow through a radiator into the engine. The radiator’s job is to keep the coolant cool so that when it returns back into the engine, it is able to absorb more heat.

A radiator fan is thus used to keep the temperature of the coolant in check. Thus, it has an important job. If the radiator fan fails or is not working properly, your car can get seriously damaged, and repairs would cost thousands of dollars.

Therefore, as soon as you feel that the radiator fan is not functioning, rush to the mechanic and get it fixed. A radiator fan can stop working due to various reasons. You need to know these symptoms to save your vehicle from a disaster.

Visual Check

When a radiator fan works it usually makes a whirring sound that is easily noticeable. However, the radiator fan does not always start spinning on ignition. The ECU signals the radiator fan to work at the precise time. So, do not worry if the fan doesn’t immediately start working. Visually check the fan if you don’t hear its noise.

1. Broken Fuse

Everything electrical is supported by a fuse so that if there is an electrical surge going towards a piece of electronic equipment the fuse cuts the electric supply to that particular equipment saving it from destruction. This is what we call a blown fuse.

A blown fuse is no big deal and changing one does not cost a lot of money. If your car’s radiator fan is non-functional first check your car’s user manual and locates the fuse for the radiator fan. If the fuse is blown simply replace it and that should solve the issue for you.

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2. Old Fan Wiring

If the fan is not working even when the car is heating up there might be a problem with the wiring. You need to inspect all the wiring leading into and out from the radiator fan. It is possible that a wire has worn out due to heat and needs replacement. All you have to do is unplug the wires from the radiator and check their integrity by using a voltmeter. If both the wires positive and negative are transmitting 12 volts of electricity then they are fit. However, if there is any irregularity in the voltage supply then that means the wire is faulty and should be replaced.

Similarly, if the wires are in perfect condition, you should inspect the relay, the task of which is to supply electricity to the wires. The relay is a small box-like structure that can wear out due to extensive use. Replace the relay and your fan should start working perfectly again.

3. Faulty Temperature Sensor

engine coolant temperature sensorThe ECU is responsible for starting the radiator fan once the engine gets hot. The ECU receives information from the temperature sensor which signals the ECU to initiate the fan. Therefore, if the temperature sensor is faulty, it is likely that the ECU is not receiving the proper signals and thus the fan is not working. You can solve this by locating the sensor found in the thermostat cover under the hood of your car and cleaning it or replacing it with a new one.

Cleaning a sensor is an easy job. There are hundreds of videos online showing you how to do that. Usually, after the sensor is cleaned it starts to work again. However, if it doesn’t, you need to replace it with a new one. A certified mechanic can help you with that.

4. Insufficient Coolant

Sometimes it feels as if the radiator fan is not working even though it is. This is possible when the amount of coolant in your system is low. You should make it your daily habit to check the coolant levels in your radiator. If the coolant level is low, you need to refill the coolant to optimum levels.

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Failing to do so could risk your engine becoming seized. There is no coming back from a seized engine unless you are willing to spend a lot of money.

5. Fan Clutch Or Belt

The fan clutch is responsible for holding the fan to the engine and turning it. If this assembly burns, you would have to replace it with a new one. If your fan is still not working after you have tried all the above-mentioned suggestions, then a failing fan clutch could be the issue.

Moreover, the fan belt could also be the issue. In older cars, the fan used to work with the help of an engine. Whenever the engine would start, the radiator fan would start spinning. This was made possible through a belt that derived power from the engine. If this belt broke, your radiator fan would stop working completely.

If you have tried everything mentioned above and your fan is still not working, then that means it is time for you to invest in a new one. Just like all other electronic equipment, the radiator fan also has a lifespan. When it has completed its lifecycle, it just refuses to work. In this case, you need to visit your nearest mechanic and consult with them. A mechanic would initially check all the other things related to the radiator fan to make a proper analysis.

Radiator Fan Cost

A radiator fan is not very expensive and can cost around $200 – $400. It’s the fan motor that makes the radiator expensive. Your mechanic would charge you $120 to $200 depending on the make and model of your car and the nature of the work.

Since the radiator is right at the front, your mechanic does not have to open any other component to remove the radiator fan. He might have to remove the radiator though which needs precision and skill.

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Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

15 thoughts on “ 5 Reasons Why Your Radiator Fan Is Not Coming On ”

  1. My problem is that the fans work when I start the vehicle but when it warms up, they no longer work! It is getting dangerous to blowing. Right now I am parked waiting for rush hour(s) to finish. Very annoying. Already replaced the fans, radiator, temp sensor and relays… I’m fitting to cut the wires and run them directly to the battery w a switch before I loose this vehicle!

  2. run a 12volt wire with a switch and just turn your fan on when it is starting to get to warm or when it needs to be on

    1. I have Toyota camry 2014 always factory maintained. After parking the car for 15 20 minutes with ac on its engine temperature goes to half and ac trips and radiator fans are off.
      When switch off the car and restart all gets fine again.
      Please advice.

  3. Thanks for your writing it’s encouraging am happy .In my car my car is suzuki Every bus the radiator fan fuse cuts often when ever i pass through water because our road water loged please help thanks

  4. hello

    I have Subaru forester 2004. The issue is with the coolant fan. it wont turn on eventhough I have replaced the temp sensor with a new one. I have checked electricity with test meter and the wiring is okay. The fan does work when you turn on the AC

    Can anyone help with this problem.

  5. Hey there i just bought used peugeot 508 and have one issue with it. The fan doesn’t work when the engine is off, it only run when i turn on the engine. Could you please help me with this.


    1. My Nissan np200 heater does not blowing warm or hot air i ‘ve even changed the old thermostat and replace with new one but still the same please help.

      1. It sounds like either low antifreeze, or possibly a bad vaccume line, that usually opens a valve, so hot antifreeze is allowed to flow flow thru heater core, in some older cars, or possibly a cable, not sure here, but thought I would throw it out there.

  6. Hi, it’s Ayanda
    I m driving proton gen 2.
    Radiator Fan is not working and the car’s temperature goes to 130, I don t know what to do

    1. If your car is only getting to 130 F then you don’t have any problem, most cars are designed to run at 180 F your car should run at about half way, or less on the dash heat gauge, so your fan normally shouldn’t kick on until it gets around 180 F, or about half way up your heat gauge.

  7. I have a 2007 Nissan Altima, several months ago the ac compressor clutch went out. Didnt have the money to get a new so I replaced it with a pulley. My car started to over heat, I think the coolant fans aren’t work, my question is Does the ac compressor clutch control the radiator cooling fan?

    1. You can have the other pulleys going in the wrong direction which will cause it to overheat. It’s better to have purchased a shorter belt for the same car without air conditioner.

  8. I have VW Sharan VR6 2,8 engine I can run the engine until is hot 50% or very hot and my engine will cut off and I must wait until it’s cool and I can start and run again what is the problem?

  9. I have a 2005 Buick LeSabre I have dual fans the one on the driver side works and the one on the passenger side does not work. Trying to locate the problem. Does not overheat
    but notice it did not come on

  10. I have a 2008 Nissan march when I start my car and after driving about 5 minutes the red thermometer light comes on the dashboard for about 11 seconds and then goes of what does that mean. Is the car overheating? IT has in enough coolant and the fans are working.

  11. Due to a very high demand and high ammount of comments, you have to wait for some time for your car questions to get answered. If you want to get fast answers from a certified master technician you can ask your questions here:
    Ask A Mechanic

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