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Car Radiator Fan Not Working (Causes & Fixes)

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A car radiator fan is important for regulating engine coolant temperature, if it stops working the engine could overheat.

The most common cause of a car radiator fan not working is a blown fuse or low coolant levels. There are also other issues that may cause this, it’s important to make sure the fan works properly to prevent overheating.

In this article, we’ll discuss why a car radiator fan may not be working, the various causes and how to fix this issue.

What Does the Car Radiator Fan Do?

The radiator fan, either mechanical or electric, plays a vital role in cooling the radiator, which subsequently regulates the engine’s temperature.

This fan can be mechanically driven by a belt connected to the engine, although electronic control is more common in modern cars.

If coolant temperatures elevate above a specific range, the cooling fan will switch on and improve airflow through the radiator, helping to lower coolant temps.

a car radiator fan up close

Causes of a Car Radiator Fan Not Working

Various reasons could cause the radiator fan to stop working. Below are common issues which may cause this.

1. Blown Fuse

A blown fuse is the most common reason for a car radiator fan to stop working. To determine whether the fuse is blown, you should find the fan fuse and test it.

Usually situated in the engine compartment or under the dashboard, the fuse box should contain this particular fuse.

In the event of a blown fuse you should replace it. When doing so, make sure you use fuse of the identical amperage rating as the original to prevent potential damage.

2. Faulty Wiring

Over time, the wiring that controls the radiator fan can deteriorate, leading to damage and eventually its failure.

The primary culprits behind damaged wiring include aging, gradual wear and tear, and exposure to environmental conditions (such as the radiator getting wet).

You can check the wiring for corrosion, fraying, or disconnected/loose wiring and plugs.

In instances of wiring damage, repair or replacement of the wiring is essential.

damaged wiring

3. Malfunctioning Radiator Fan Clutch

The radiator fan clutch links the fan to the engine, enabling it to engage and disengage.

If the clutch malfunctions, the fan cannot activate, regardless of normal functioning power supply and wiring.

To identify this problem, a thorough examination of the fan clutch is needed, check for indications of damage, deterioration, etc.

In cases where a faulty fan clutch is found, replacement is necessary.

Note that not all vehicles have a radiator fan clutch. Most modern vehicles have electronically controlled fans.

4. Low Coolant Levels

Inadequate coolant levels within the engine can result in insufficient cooling, increasing coolant temperatures above the desired range leading to overheating.

When the ECU detects an elevated coolant temperature, the radiator fan will switch on.

Check the coolant level of your vehicle if you suspect the radiator fan is malfunctioning or always staying on.

topping up the coolant level

5. Faulty Coolant Temperature Sensor

The coolant temperature sensor plays a crucial role in keeping the engine’s temperature within appropriate limits.

A malfunctioning sensor could lead to a failure in activating the radiator fan when necessary, posing a risk of engine overheating.

To address this, a diagnostic assessment of the coolant temperature sensor is required, employing either a multimeter or a diagnostic tool.

If the sensor is determined to be defective, replacement is the recommended course of action.

6. Faulty Radiator Fan Motor

The radiator fan motor propels the fan and governs its activation and deactivation. A malfunctioning motor impedes its ability to turn on.

To address this, a diagnostic evaluation of the fan motor is necessary, by either a multimeter or a diagnostic tool. If the fan motor is identified as faulty, replacement is the recommended solution.

How to Check if the Radiator Fan Is Working

There are a couple of ways to check if your radiator fan is working.

  • Listen for the fan: When the engine coolant reaches elevated temperatures, the fan should activate. Pay attention for the sound of the fan starting up. However, the fan will only activate if the coolant gets hot, such as when sitting in traffic on a hot day, or while driving hard.
  • Turn on the AC: In some vehicles, the cooling fan turns on by default when the AC is switched on. However, this is not the case for all cars.
  • Testing of the fan relay, motor and fuse.

You can read more about how to test a radiator fan here.

How Much Does It Cost to Fix

The cost of fixing a radiator fan depends on the cause of the problem and the parts that need to be replaced. Below are some estimates of the cost of common repairs.

  • $80-$250 (£58-£178) for a new radiator fan
  • $80-$150 (£58-£107) for a new fan motor

Please bear in mind that these figures are estimates and the actual costs may differ based on your location, your vehicle’s make and model, labor charges, and the extent of the issue.

How Long It Takes to Fix

The time needed for repairing a radiator fan depends upon the cause of the issue and the complexity of the repair needed.

Typically, replacement should take 1-2 hours.


If a car radiator fan is not working, it’s important to fix the issue as soon as possible. If not, it can cause the engine to overheat, leading to serious damage.

Several causes exist, including a blown fuse, faulty wiring, a malfunctioning fan clutch, low coolant level, or even a faulty coolant temperature sensor or motor.

  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer.He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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