Mac Fixes

How to Diagnose and Fix a Noisy Mac Fan

Apart from a few exceptions, like the 2020 MacBook Air and the 2015 MacBook, all Macs have cooling fans. Processors and other electronic parts all generate heat when they’re used. And the more you use them, the hotter they get.    

 

Most of the time, you won’t even notice the fans running. They usually hum along quietly in the background. But do something more demanding like video editing, and they may start to spin faster, making more noise in the process.

 

Sometimes, though, they’re excessively noisy or they might kick in when you’re not doing anything with your Mac. In that case, you might be wondering why your Mac’s fans are so loud.  

 

In this guide, we look at some of the potential reasons for loud fans in a Mac, as well as things that might fix the problem. Of course, we can’t know for sure why your particular Mac is having problems with its fans, so it’s worth working your way through these tips.  

 

Before we start

 

Sometimes, problems with third-party software can cause your Mac to overheat. It’s a good idea to make sure all your apps are up to date — and MacKeeper can help, with its Update Tracker feature.

  1. Select Update Tracker in MacKeeper’s sidebar
  2. Click Scan for updates
  3. Select all apps you want to update, and click Update  

MacKeeper is a complete security and optimization tool for Macs. Try it out today to see what else it can do. You get one free fix for each tool, so you can test it properly.

Check your Mac’s vents aren’t blocked

The fans in your Mac work by pushing warm air out and pulling fresh air in. If any of the vents are blocked, that can’t happen, so your Mac keeps getting hotter — and the fans keep speeding up to compensate.  

 

This happens a lot with MacBooks when users place them on soft objects like beds or cushions. So if your MacBook is running loudly, try moving it to a hard, flat surface, like a table or desk.  

 

With all types of Macs, you should also make sure the vents aren’t clogged up with anything. If they are, use a brush to clean them out.  

Clean dust out of your Mac

One of the big problems with fan-based cooling is it draws in dust as well as air. Over time, that builds up and sits on the motherboard and components like a blanket. Removing this dust can stop your Mac overheating and producing loud fan noise. If you own a Mac Pro, you can simply pop off the side and clean it out, but you can’t do that with other models.  

 

What you can do is get a can of compressed air and try to blast some of the dust out. A vacuum cleaner could also do the trick but be careful, especially if you have a powerful vacuum cleaner.  

Stop processes with high CPU usage

When your Mac’s processor is under high load, it will heat up. The more it has to do, the hotter it will get. Using the Activity Monitor app, you can stop your Mac’s loud fan noise by shutting down whatever is making your processor work so hard.

 

How to stop processes with the macOS Activity Monitor:

 

1. Go to Applications > Utilities, and open Activity Monitor

Applications > Utilities folder

2. In the CPU tab, click the top of the % CPU column to sort by highest first

Activity Monitor > % CPU column

3. If anything is using an excessive amount of CPU time, select it and click the X button

Activity Monitor > click the X button

4. Click Quit to shut the process down

Activity Monitor > Quit a process

Bring down the ambient temperature

It might seem obvious, but if you’re in a hot room, your Mac will be hot too. That could be enough to make it spin up its fans and start making a noise.  

 

The fix is quite simple: bring down the temperature in the room by opening a window or lowering your heating. You could also aim a desk fan at your Mac to help it cool down.  

Check for hardware problems

Faulty components can sometimes produce excessive amounts of heat. But that’s not the only potential hardware problem — Macs have several heat sensors inside them, which tell the fans when to spin faster. If these sensors break down, that could also cause your Mac’s fans to spin faster and louder.  

 

Using macOS’s built-in Apple Diagnostics, you might be able to find the source of the issue. However, there are no guarantees that this will work.  

 

Here’s how to run Apple Diagnostics on an Intel Mac:

  1. Turn on your Mac, then press and hold the D key
  2. Keep holding it until a list of languages
  3. Pick a language, and Apple Diagnostics will run automatically, spitting out a result at the end

On an M1 Mac, you can run Apple Diagnostics like this:

  1. Turn on your Mac by pressing and holding the power button
  2. Release the power button when you see the startup options
  3. Now, press Cmd + D to load Apple Diagnostics

Reset your SMC

You can fix many problems in Intel-based Macs by resetting the System Management Controller (SMC). This controls various components on your Mac, including the power supply, lights, and of course, the fans. The process for resetting your Mac’s SMC is different depending on which model you have.  

 

Here’s how you reset your SMC on an Intel desktop made from 2018 onwards:

  1. Turn off your Mac, and unplug the power cord
  2. After 15 seconds, plug the power cord back in
  3. Then, after another five seconds, turn your Mac on again

For other models of Mac, check Apple’s official guidance.  

Check for malware

Malicious software can do a couple of things that make your Mac’s fans run constantly or louder than normal. It can increase load on your processor, which will cause excess heat. Or it can take direct control of your fans. In fact, it’s been shown that hackers could modulate fan vibrations to transmit information through sound waves.    

 

You can scan for malware using MacKeeper like this:

 

1. In MacKeeper, select Antivirus from the sidebar

 

2. Click Start scan

MacKeeper > Start Antivirus scan

3. Let the scan run

MacKeeper > Antivirus scan

4. If it finds anything, select it and click Move to quarantine

MacKeeper Antivirus > Move to quarantine

Related reading: How To Remove Viruses and Malware From Your Mac

What to do if your Mac’s fans still won’t turn off

If your Mac is overheating or if the fans are loud even when it’s cold, it could have a more serious problem. That could be software or hardware related. In the case of faulty hardware, there’s little you can do except try to get it repaired. Contact Apple support or a qualified repair service, and they will likely be able to help you.  

 

Usually, though, when a Mac’s fans are making a lot of noise, the solution is simple. Hopefully, one of our tips here will do the trick for you.

FAQ

What will happen if my Mac’s fans stop working?

If your fans stop working completely, your Mac will just keep on getting hotter and hotter. Eventually, it will shut itself down to stop components being permanently damaged. This can also happen if your Mac’s vents are blocked.  

Can I control my Mac’s fans manually?  

By default, no. Your Mac will spin your fans as fast as it thinks it needs to in order to stay cool. You can, however, download software that lets you control your Mac’s fans manually. If you know what you’re doing, this can be useful, but it’s also risky — which is why we’re not recommending any fan control solutions here.  

How much heat is normal?

Macs can generate a lot of heat and still operate safely. For example, Apple says the normal operating temperature of a MacBook is between 50ºC and 95ºC. So don’t worry if your Mac feels warm when you’re using it.  

 

Read more:  

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