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Should a Fan Clutch Spin Freely When Cold or Hot? (Answered)

We travel to different places frequently whether it be for work or other events. Some people prefer to use public transport to travel whereas others prioritize the comfort of their private traveling.

However, with the comfort of owning a vehicle comes the responsibility. You can learn the relevant information about a vehicle’s maintenance below.

Should a fan clutch spin freely when cold or hot?

A fan clutch should not spin freely whether it is cold or hot because a properly functioning clutch should face enough resistance to prevent it from spinning freely. A good fan clutch spins freely if a significant amount of force is applied but if it spins on a small force, then it is going bad.

A fan clutch’s function is to cool your engine and control the air temperature of the radiator. The thermostatic property of the fan clutch allows its spring to slowly expand as the engine starts to heat up and function optimally.

At warmer temperatures, the fan spins faster to prevent the engine from overheating, whereas it spins comparatively slower at lower temperatures to warm up the engine.

If the fan clutch is faulty, this temperature control will not take place and therefore the engine might face overheating – leading to other problems as well. Temperature does matter in case of its ease of turnability.

A fan clutch should not freely spin unless it is at its operating temperature.

Generally, a faulty fan clutch should spin well around or more than five times a day the vehicle has not been used if you have tried to spin with the maximum force possible. A properly functioning fan will put up resistance as you try to forcefully spin it.

At what temperature does a fan clutch engage?

Fan clutches function as the cooling mechanism for an engine but they also have to reach a certain temperature to be able to do their job optimally. As you start your engine up, it begins to heat up as well as the fan clutch – causing its spring to expand as well.

As the temperature of the engine reaches the range of 180 to 190 degrees Fahrenheit, the air temperature should be well around 170 degrees Fahrenheit, which is the temperature at which the fan clutch would engage.

Once the fan clutch is completely engaged, it should only then spin freely at its maximum efficiency.

Therefore, unless the fan clutch is at its engaging temperature, it should be tight enough to not spin freely. A lack of resistance signifies that it has gone bad and thus it will be unable to cool down the engine when it overheats.

How stiff should a fan clutch be?

When the engine is not running or the temperature is not around the fan clutch’s engaging temperature, then there should be some natural resistivity to it. Whenever you try to manually spin it, a properly functioning fan clutch will not spin.

There is a way to test out and get an estimation of whether the fan clutch is good or has gone bad from observing how stiff it is. The stiffness of the clutch will be measured by the number of free spins the fan does before it comes to a halt.

Other than electronic variants, traditional fan clutches will not freewheel without applying some force.

The clutch should spin for a maximum of three to five times freely before coming to a stop when the engine is cold. However, if you see that the clutch is sloppy and spinning freely sometimes with a squealing noise, then your clutch has gone bad.

What causes a fan clutch to fail?

A fan clutch may fail due to a variety of reasons, ranging from fluid leaks to faulty thermostatic springs. If your fan clutch is not operating the way it should, then it is due to the fluid leak of the fan clutch or a bad thermostatic spring or valve.

In case of fluid leaks, they are due to faults at the bearing seal located at the center rear of the fan clutch, which results in the fluid dropping into the clutch and jamming it well enough to cause it to get sloppy and not spin as fast as it should.

Another probable cause is a faulty thermostatic spring that causes premature clutch engagement – resulting in a faster spin. Although that does not allow the vehicle to overheat, it does behave abnormally.

How to diagnose a bad fan clutch?

Other than the freewheeling of the fan clutch, there are several other ways to determine and confirm whether your fan clutch is functioning well or has gone bad. The methods of diagnosis are listed below:

Check for unusual temperature spikes:

A fan clutch’s job is to prevent your vehicle from overheating but if the fan clutch is faulty, your vehicle will start to overheat at low speeds or when idle such as at the stoplight or in heavy traffic. However, the temperature does not spike at higher speeds even if the clutch is faulty.

This is because of the air flowing from the front of the vehicle to the motor that cools down the engine.

Loud noises from the fan clutch:

A faulty noisy fan will be noticeable at all speeds because it will continuously make a squealing or scraping noise.

The reason is that the fan clutch is being kept engaged all the time the engine is running whereas it should only be engaged when the vehicle is either hot or running at low speeds or idle.

Being engaged all the time will cause it to consistently keep making a metallic scraping noise.

Lower the spinning speed of the clutch:

When you start the engine of your vehicle, you should notice the rotation of the fan clutch. The fan clutch should spin faster and with increasing speed as you step on the gas pedal.

However, if you notice that the speed of the fan clutch remains the same no matter how you press the gas pedal, then it is a sign that the fan clutch is faulty.

How to fix a bad fan clutch?

Fixing a fan clutch is essential since it is vital for maintaining the longevity of your vehicle. If you have a bad fan clutch, you can either choose to replace it or try a temporary solution if you are out in the streets. Both methods are described below:

Temporary Fix:

You will need a hose clamp, duct tape, and a tire plug for this. Take the tire plug and press it down into the tiny cavity between the nut connecting the clutch. Afterward, make sure the tire plug is firmly in place by wrapping it around with duct tape.

Lastly, tighten them up with a hose clamp to make sure the tire plug stays in place while spinning.

This should not be a permanent fix and requires you to drive at lower speeds so that the rotation per minute is less and the tire plug doesn’t melt.

Fan clutch replacement:

First off, you need to take off the air filter and the pipe that is on top of the fan clutch to uncover it. Once that’s done, you will need to use a wrench to unscrew the bolt that connects the fan clutch to your vehicle.

You can try and use your replacement fan clutch to determine which way to rotate your wrench.

But first, you need to remove the belt holding the clutch by rotating one of the pulleys with a ratchet. Next, use the wrench again to remove the belt frame off the clutch.

Afterward, you would be able to remove the clutch with a wrench – replace the old clutch with the new one and fit it back in place.

How free should a fan clutch spin?

Your fan clutch is not supposed to move freely, if it does then it is faulty and requires a replacement. However, do not be misled if you see our fan clutch spin because there is a limit to how freely a fan clutch should spin.

Generally, a fan clutch is tight and does not move completely freely when the engine is cold, however, if the clutch has gone bad it will spin by a considerable amount. Try to spin the fan clutch and observe its rotation.

If it rotates without much effort and spins more than 4 times – it is faulty.

But if you have to use some force and it spins no more than 4 times, then the clutch is in good shape. You should also check the belt or pulley if your fan clutch is moving too freely.

Final Thoughts

A properly functioning fan clutch should not spin freely whether it is cold or hot and should overcome enough resistance to spinning freely. Regardless of the temperature, if the fan clutch is spinning freely under minimal force, then it is a sign of a failing fan clutch.