Bad Radiator/Cooling Fan Symptoms

Has your car ever stopped on the road because of overheating? Most probably it is the radiator of your car which is not getting the cooling air that it requires. An overheated car can not only stall the car but also seriously damage the engine. 

The radiator cooling fan is mainly responsible for bringing in the cool air and if the fan does not work properly, you will notice a series of problems. All modern vehicles have a radiator fan and usually they work well for a long time. But, are you aware of the signs that you must look for and identify the reasons to know why the car in this condition? Well, there are some symptoms which you can easily identify and take the car to a garage as soon as possible and avoid serious damage. 

Some Of The Signs Of A Bad Radiator And Cooling Fan

Before you get your car fixed, you should be able to identify the problem. Understanding the minor signs and indications that your car gives before any problem arises is very important. 

  • An overheated engine is the most common sign of a bad radiator cooling fan
  • The A/C could start to perform badly
  • Whirring or other sounds coming from the engine box

The radiator fans are situated close to the radiator and help in maintaining the right temperature. The fans pull air through the radiator slats especially when you keep the car idling or at low speed. Very little air passes through at low speeds. 

Cooling Fans And What Do They Do?

Cooling fans have electric motors, and they work like any other electric motor used in other gadgets. The best part is that the cooling fans are easily replaceable, and you can get a new one when the old one fails. The fan spins and generates air and keeps the engine bay well-ventilated. In hot weather and on warm days the fan works harder to maintain the right temperature. 

A cooling fan has three major parts which work together effectively. 

  • Blades: these are attached to the engine or radiator and spin when cooling is needed
  • Charging system: the car provides the juice to the fan for it to work
  • Motor: the electric motor is attached to the charging system

Many modern engines feature passive radiators. Such radiators keep the car cool in a very different way. Usually, an aluminum block is used that has no moving parts and depends on the airflow over their surface to bring the temperature down. When you work with your car engine you can feel the warmth of the block. This heat is replaced by the flowing air passing over the radiator surface. The cooling fans need to work immediately and effectively as soon as the engine starts up, so there is no overheating of the passive radiators, otherwise, there could be serious damage.  

Test For Bad Radiator/Cooling Fan Symptoms

Is there any way you can test whether the cooling fan is working well? This can help you prevent any bigger problems which may be caused if you ignore the issue. 

  1. At this juncture the best thing to do would be to stop the air conditioning and try starting the car.  Once, the car starts, turn on the AC, go and look at the engine block. You should be able to see the cooling fan spinning at a good speed and making the airflow in and out. 
  2. Another way you can test the efficacy of the cooling fan is by placing a hand in front of the engine. If you notice a lot of heat coming from there, then it is suggestive of the cooling fan not working properly.  
  3. If you start the engine and the fan does not switch on, then you surely know something is wrong. The problem could be with the electric motor or in the relay of power from the car to the electric motor. 
  4. If you notice the radiator fan working intermittently and causing problems occasionally, then you need to check the control module or loose connectors to pinpoint the problem. 
  5. If you notice that the radiator circuit fuse is blown, it is a symptom of the radiator fan not working properly. The circuit fuse is designed to blow when there is a surge or fluctuation of power, to keep the system safe. Once you change the fuse, the radiator fan will start to work.
  6. Some cars have a temperature warning light. If you see this light come on, chances are that the radiator fan is not working properly and causing the rise in the temperature. 

Here Are A Few Conditions Under Which A Radiator Fan Might Stop Working

If the radiator fan is not working in your car, there could be several reasons for this. Some of the main causes are: 

  • Electric cooling fans have a fan relay and over time with exposure to heat and current, it may stop working and lead to fans not working as well. 
  • The radiator fan fuse protects the wiring system and other electrical parts as the current doesn’t pass through the fuse.
  • The wires and connectors used in the fuse and relay can break and interrupt the current flow. They may also come loose or accumulate dirt and cause problems. 
  • When the fan motor fails, either due to the bearings and brushes wearing out or burning of the coil, it will not allow the fan to work.

Frequently Asked Questions

Q. How long can a radiator cooling fan last? 

A. It depends on the car, the weather, type of cooling fan, etc. but on average, a cooling fan can last up to ten years. 

Q. What sound does a bad radiator fan make? 

A. You may notice loud whirring or clicking noise every time you rev the engine. There may be other sounds depending on the type of damage. 


Bad radiator cooling fans can cause severe engine damage. It is important that you are able to catch the problem early and take remedial action in time. Once you learn about the various symptoms of a bad radiator fan, you will be in a better position to handle the problem effectively. Whatever you decide, it is best to not waste much time and get it repaired or replaced fast for the engine to continue working smoothly. 

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.