What Are the Reasons for Fan Noise After Engine Turned Off?

Introduction to the topic

When you turn off your car, it doesn’t always look like everything is turned off. Even after turning off the engine, the car may make strange noises. Some vehicles have their engine cooling fans and other components set to continue working even when the engine is turned off.

You pull into parking, turn off the car’s engine, and get out to go. Then you realise the automobile is turned off, but the engine cooling fan is still operating.

The engine cooling fan can continue to run for a few minutes after you turn off the automobile without damaging anything. After you turn off your automobile, the fan will stay on for a few minutes.

Many cars, including bmwsand Mercedes-Benzes, operate this way. There have been reports of radiator fans running for as long as five minutes.

It might remain permanently on until the battery dies, barring any electrical problems.

When the motor is in operation, the coolant is pumped via a system of pipes and out through the radiator to disperse engine heat. The engine takes a longer time to cool off when it is shut off because the coolant stops flowing. The engine might continue to be cooled by the running cooling fans even after you have turned off the vehicle.

My car’s engine fan keeps running even after I turn off the engine; what does this mean?

If your radiator fan continues to run after the engine has shut down, it’s because you have an electric fan and the manufacturer likely intended for it to do so.

Absolutely typical.

A problem would arise if it never turned off.

The radiator fan in your engine is likely connected to a circuit that is not controlled by the ignition, and the engine temperature is still too high for the fan to turn off. If they’re on for more than two or three minutes, something is wrong with the sensor or switch that controls the device.

What are the causes if noisy fan, after engine shut down?

An abnormally loud radiator fan is something you may experience occasionally. Why, then, is this occurring? When a radiator fan is malfunctioning, it can produce a lot of noise. Sometimes the cooling fan will be noisy for no other reason than that it is working hard. There is no issue with the actual fan in these circumstances.

For this reason, we have compiled a list of the top 5 explanations as to why your car’s cooling fan may be running louder than usual.

1. A radiator fan that has been running due to dirty blades will increase in volume

If the blades of your car’s cooling fan are unclean, the fan will have to work harder to move air. In comparison to typical, this will make a lot more noise. If you regularly drive your automobile at high speeds or under heavy loads, you may notice an increase in engine noise as a result of the increased engine temperature.

Overheating concerns within the vehicle can occur when airflow is restricted by a dirty blade, especially in the summer when outside temperatures can soar to well over 100 degrees Fahrenheit.

2. Sensors for measuring temperature

This can also be caused by a broken temperature sensor. The feedback from the temperature sensors controls the operation of the coolant fans. A malfunctioning sensor may be misreading the situation and causing the fan to run constantly.

3. Electronic control unit

To put it simply, if the coolant system is still hot, the ECU unit will instruct the fan to keep running. The electronic control unit (ECU) is hardwired to the earth and controls the fan’s on/off functionality. A faulty ECU prevents it from turning off the cooling fan at the appropriate time.

A fan is operating to help disperse the hot air. Therefore, having the fan continuing operating after turning off the vehicle is abnormal. A professional technician should look into this.

4. Noise can be produced by a vehicle’s radiator fan if the belt is loose or broken

The cooling fan may generate a lot of noise if the fan belt is loose or broken. If it happens, the engine heats up and the fan has to work harder than it has to in order to keep the car running.

That will increase the overall volume of the car’s noise. If you don’t get it fixed right away, your automobile could sustain even more damage.

The fan belt in your vehicle should be inspected every few months for wear and replaced if necessary.

5. Whenever the radiator’s air intake is obstructed, the car makes an annoying racket

When there is insufficient airflow around the radiator, the fan on a car radiator will become loud and noisy. One possible explanation is that leaves or other debris have become lodged between the grill and the body of the automobile, or that something is blocking the air vents.

If this is the case, it’s usually a simple matter of clearing out the vents and removing any obstructions.

When the engine is shut off, how long should the fan continue to run?

As for how long the car fan can keep going once the ignition is turned off, the general consensus is 5 minutes. This is something that changes from make to make and with mileage.

It may take a little longer for the cooling fan to turn OFF if the automobile has been driven for a long time.

The engine is cooled by the fan’s removal of excess heat. This means that you can leave the car’s fan on for a few minutes after you’ve switched the car off.

Leaving the car’s fan on for at least two to three minutes after turning off the ignition is recommended, and up to five minutes is even better. Over this threshold, there is probably an issue with the vehicle. Disconnect the battery terminal if your fan keeps running for more than 30 minutes (especially the negative side). Doing so will keep the fan from using too much power and killing your battery.

When does a bad relay in a cooling fan mean trouble?

An excessive rise in temperature is the first indicator of a faulty cooling fan relay fan. An fault with the cooling fan relay may be to blame for an unexpected and rapid rise in temperature.

The failure or poor operation of the fan is another symptom of a faulty fan relay. After 15–20 minutes of cranking the engine, if the cooling fan still doesn’t turn on, the problem may lie with the relay that controls its operation.

Again, the cooling fan relay may be at fault if the fan continues to run after the automobile has been turned off.

Overheating the engine can cause irreparable damage, thus these symptoms warrant an immediate visit to the mechanic.

When the engine fan won’t stop spinning, what should I do?

You can turn off a running fan by removing the negative battery connector.

Turn off the fan and unplug the negative end of the battery line if it has been running for more than 30 minutes.

Replace the faulty fan relay with a good one that uses the same pin configuration for testing. Checking the cooling fan relay with a digital multimeter is another option.

It’s the relay’s issue if the fan stops working.As an added precaution, look for leaks and low coolant levels. When the coolant level drops, the engine temperature rises. As a result, it will turn on the fan more frequently.

Watch Why does my car buzz after i shut it off | Video

People also ask questions and answers related to Fan noise after engine turned off

When I turn off the engine, why does the fan continue to run?

Some cars’ fans will continue to spin for a few minutes after the ignition is turned off; this is done to preserve engine temperature. The fan will wear out from usage if it is left on for too long.

When I turn off the engine, why does my car engine continue to make a humming sound?

Bing – Approximately 5-10 hours after turning off the engine, a rumbling may be heard from below the car. But that’s not a sign of a problem either. The gasoline evaporation leakage testing system is producing this noise during regular operation.

When a cooling fan switch stops working, what happens?

Overheating, the illumination of the Check Engine Light, and a malfunctioning or diminished signal wire are all common warnings.

My engine cooling fan seems to be unusually noisy, what could be the reason?

A screeching, howling, or other unwelcome sound coming from a fan is usually the result of worn bearings, bent or broken blades, or unbalanced spinning assembly. Removing a worn fan and replacing it with a new one isn’t a major hassle, thankfully.

What symptoms indicate a broken radiator fan?

Warnings that your radiator fan assembly needs to be replaced include:
Vehicle’s engine has overheated. The engine temperature rises because the radiator fan is not able to conduct its job effectively.
Reduced AC Performance…
Radiator Fan Making a Terrible Racket.


There are a few reasons why your car’s cooling fan might be loud recently. Here are the five most prevalent explanations for a noisy car cooling fan.

If you can figure out why your car’s cooling fan is louder than usual, you may take measures to quiet it down and keep your vehicle in good working order.

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