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Buzzing Noise After Turning Car Off – 6 Potential Causes & Solutions

Hi, I'm Azim Uddin, a student who loves cars. Visit carcaresite.com to learn about car maintenance for beginners and experts. In my studies, I found a cool connection between hosting and car care. Join me on this journey where every road has a story, and hospitality meets the thrill of cars. Explore, learn, and enjoy the ride with me!

Hi, I'm Azim Uddin, a student who loves cars. Visit carcaresite.com to learn about car maintenance for beginners and experts. In my studies, I found a cool connection between hosting and car care. Join me on this journey where every road has a story, and hospitality meets the thrill of cars. Explore, learn, and enjoy the ride with me!

Last Updated on May 9, 2024 by Azim Uddin

Apart from the warning lights, unusual car noises when idling, accelerating, or braking are other common signs of car trouble. However, your car can also make different noises, like buzzing or humming, after turning it off.

So then, what causes buzzing noise after turning car off? A buzzing sound after switching off your car occurs due to an issue with the fan. It can also transpire due to some vehicle components like the vacuum pump, after-run pump, and throttle body still running. Sometimes, a problem with the AC can cause the buzzing.

Interested in learning more? In this post, we will discuss everything you need to know about the buzzing noise and how to fix it.

What Does Buzzing Noise After Turning Car Off Mean?

Typically, the buzzing noise from your car after turning it off can sometimes be normal or unusual. Below is what the noise could mean.

What Does Buzzing Noise After Turning Car Off Mean?

In some vehicles like the Ford Focus ST2 and Land Rover Discovery II, you may hear a buzzing noise from the dashboard area. The noise usually happens occasionally and can be louder or quieter.

The common cause of the noise is a loose, dirty, or faulty small fan located below the steering wheel. This tiny fan is used to monitor cabin air. If the fan is not seated correctly, it will vibrate against the panel, causing a buzzing sound.

buzzing noise from dashboard are

There are at least 3 effective ways to eliminate the buzzing noise caused by the small fan. These include:

  • Tighten the Fan

If the small fan is loose, you simply reach under the steering wheel and put it back into place.

  • Clean the Fan

Sometimes, the fan can make a buzzing noise due to dust and dirt built up. In this case, you simply blow it out with compressed air or a shop vac to clean it.

  • Replace the Fan

If cleaning and retightening the small fan does not fix the noise, you can replace it as it could be faulty.

See also  Grinding Noise When Turning Engine Off! 4 Major Reasons?

With most vehicles, you may notice a buzzing noise coming from under your car after turning it off.

It occurs when the vacuum pump located inside the fuel evaporation leakage check module (ELCM) is running some self-checks. The pump is designed to come on about every 5 to 10 hours for at least 15 minutes after shutting off the engine.

Generally, this noise is nothing to worry about and does not indicate an issue with the vehicle. Therefore, there is no fix required.

Sometimes, you may hear a buzzing noise from the engine on the driver’s side just below the hood. This is common with turbocharger engines such as the FIAT 500 and Jeep Grand Wagoneer.

These vehicles come with an after-run pump for cooling the turbo after you have shut off the engine. The pump can run for up to 20 minutes as it circulates coolant to cool down the turbo.

You simply learn how to live with the noise. This is because it is normal and not an indication of a problem with your car.

If your vehicle’s AC does not get warm enough or very cold, it could be under-gassed. When this happens, you may hear a high-pitched buzzing sound for at least 5 minutes after turning off your car’s engine. The noise usually comes from under the right-hand side of the bonnet.

Sometimes, this could happen due to the AC being under-gassed. It can also occur when the valve controlling the flow of the refrigerant becomes partially seized due to inadequate lubrication. It is a common issue with the 2004 Jaguar X Type 2.5 and 2011 Alfa Romeo Giulietta.

Start dispensing the refrigerant fluid into the AC

Add some lubricant to the valve controlling refrigerant flow. If the buzzing sound persists, you must recharge your car’s AC using a charging kit and some refrigerant. Here is how to do it:

  • Step 1: Locate your AC’s low-side pressure port between the compressor and evaporator. You can check your car’s service manual if in doubt.
  • Step 2: Unscrew the cap on the port.
  • Step 3: Hook the hose with the gauge into the open port, ensuring a secure connection.
  • Step 4: Attach the hose to the can of refrigerant.
  • Step 5: Start dispensing the refrigerant fluid into the AC, following the instructions on the package. Make sure to monitor the pressure readings on the gauge to avoid overcharging. The correct pressure can range between 25 and 55 psi, depending on the ambient temperature.
  • Step 6: Remove the hose and gauge from the port and screw the cap back.
See also  Fan Noise After Turning Engine Off: Here’s Why And How To Fix

For a more detailed explanation of how to recharge your car’s AC system, watch this video:

The electric cooling fans are designed to run in brief after shutting off your car while the engine is hot. This helps dissipate heat from the radiator and engine.

So, as the fans spin down, you will hear a humming or buzzing sound under the hood. However, the fans usually shut off after a few seconds.

The cooling fans running after turning the car off and producing a buzzing sound are never unusual. This is as long as the noise does not linger longer. 

Some modern cars feature an electronic throttle body driven by an electric motor. The throttle body is built to do a full close-open-close sweep after turning off the car. It is like doing an alignment.

This helps determine the throttle position sensor voltage since the power control module wants to know the voltages. After all, the voltages can change due to carbon buildup.

Typically, this issue happens with many vehicle models, including BMW. However, a buzzing or humming noise from the throttle body should only last about 20 seconds and end with a clicking noise.

There is no solution to the buzzing noise since throttle body sweeping is a normal process.

Why does your car make a buzzing noise when turned off?

A common issue contributing to car problems, particularly the unsettling phenomenon of a “car buzzing when off,” often stems from issues related to the car audio system.

Many high-wattage subwoofers can inadvertently cause internal damage to the metal tube’s invisible part on the center layer, reaching up to the engine. The repercussions may include the gas cover cracking open in some cars.

This predicament is more prevalent in new cars, requiring a break-in period for their components. If your vehicle experiences prolonged buzzing, it’s crucial to assess the battery’s health. Using a multimeter, measure the voltage, ideally reading between 12.0 to 12.6 volts DC, indicating a fully charged battery.

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If the voltage falls below 12.0, using a car charger becomes necessary. If charging proves ineffective or the voltage remains below the threshold, a defective battery necessitates replacement.

For those unfamiliar with the process, seeking assistance from a qualified engineering professional is advised to address the car’s buzzing quandary when turned off.

If your vehicle experiences a persistent buzzing noise after turning the car off, you might find our articles on ‘Whirring Noise After Engine Off: Causes & Solutions’ and ‘Fan Noise After Turning Engine Off: Here’s Why And How To Fix’ particularly insightful, encompassing a comprehensive array of information. Our detailed guide on whirring noise after the engine is off delves deeply into the underlying causes of the issue and presents a meticulous step-by-step solution approach to address each potential culprit. Meanwhile, our comprehensive article on fan noise after turning the engine off provides an exhaustive exploration of all relevant aspects, equipping you with everything you need to know to diagnose and resolve the problem effectively!

FAQs

Before we conclude, let’s check out some frequently asked questions regarding the buzzing noise after switching the car off.

Q: How long should the buzzing noise last after turning the car off?

The time varies based on the cause of the noise. In some cases, it can last for 10 to 20 seconds. But if it is related to the vacuum pump or after-run pump, it can last up to 20 minutes.

Q: Is it safe to ignore the buzzing noise?

While the buzzing noise is usually typical in most cases, you should not ignore it, especially if it lasts longer. This is because it could be a symptom of something being wrong in your car.

Q: Can you fix the buzzing noise problem yourself?

Yes, if the problem is related to the AC system or the small fan around the steering wheel. However, this is as long as you have the right tools and basic mechanic skills.

Outro

Buzzing noise after you have turned off your car is a typical issue in most car models and makes. The good news is that, for the most part, the noise is usually not a cause for concern. This is because it is normal and does not last for long. Even better, the buzzing is sometimes low-pitched. That said, if you hear a buzzing sound under your vehicle’s hood, you should have it checked by a professional mechanic. This is especially important if the noise is accompanied by warning lights or unusual symptoms like the battery dying.

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