Why Is My Microwave Making a Loud Noise?

Microwaves are usually pretty hassle-free appliances – you put in your food, press a few buttons, and you’re good to go! If you’ve noticed your microwave has started to make a loud noise while operating, you’re probably feeling concerned. While noisy operation can point to serious issues, there are some simple fixes you can try to repair the problem – read on for our top tips. 

What Causes Microwave Noises?

All microwaves make some noise, but unusual or suddenly increased levels of noise are a red flag that there are some deeper issues. There are a few different components in your microwave that make noise – these include:

• A faulty magnetron can make a louder-than-normal buzzing or humming sound. 
• A faulty fan, which can make rattling or clunking noises. 
• A misaligned turntable can make grinding, clicking, or squealing noises. 
• General wear and tear and loose parts can cause vibrating noises.
• Spilled food or debris in the microwave can cause crackling noises as it cooks and burns. 

What Is A Normal Level Of Noise?

A functioning microwave doesn’t need to be silent, but it shouldn’t be noisy, either. A typical microwave will make a soft humming sound while it is operating, with sounds emanating from the fan, magnetron, and turntable. You may also hear increased noises while your food is heating, such as minor crackling or popping. 

While it’s hard to quantify exactly how loud is too loud, a good rule of thumb is that your microwave shouldn’t impair your ability to have a conversation in the kitchen. Sudden changes to the noise your microwave is making are also a good indicator that something isn’t right and needs to be investigated. 

Food Debris

If you’ve been hearing a crackling or popping sound, inspect your microwave interior for food debris. Spills and food scraps can repeatedly heat and burn with each use of your microwave, leading to loud noises every time you use it. 

• Remove the turntable plate and roller ring, and soak them in a sink full of warm, soapy water. 
• Thoroughly wipe down your microwave interior with a microfiber cloth dipped in a mild detergent solution. 
• If there are any hard-to-remove spots, coat them in a paste of baking soda and water and leave them for half an hour before removing. 
• Once the interior is clean, replace the tray and roller ring and try heating some food to check whether the issue has been fixed. 

Faulty/Obstructed Fan

The microwave fan provides ventilation and lets hot air escape from the microwave’s interior. If the fan is faulty or obstructed in some way, it can cause grinding or rattling noises. Here’s how to check if this is your issue:

• Check your microwave manual to find out the location of the fan, then listen for the source of the noise – if it seems to be coming from the fan location, this may be the cause. 
• Unplug the microwave and remove any necessary panels to access the fan. This will differ depending on your model – check your manual if you’re having issues. 
• Check the fan blades for obstruction or damage. Spin the fan manually – if it doesn’t spin smoothly, or if it looks cracked or otherwise damaged, it will need replacing. 
• Purchase a replacement fan to ensure it will fit in your microwave model. Remove the faulty fan blade and replace it with the new one. 
• Put your microwave back together and restore power. Then, run a test to see if the noise is gone. 

Turntable Issues

If the turntable is obstructed or the tray or roller ring is misaligned, this can cause loud noises while your microwave operates. To check for these issues:

• Open your microwave and check that the glass tray is properly fitted onto the grooves on the turntable and the roller ring. 
• Check the wheels on the roller ring for damage or obstructions. If there is any damage, you can purchase a replacement roller ring from your microwave manufacturer. 
• Try rotating the turntable motor manually – if it feels stuck or makes a strange noise, then it will need replacing. 

Once you determine the turntable motor needs replacing, follow these steps for easy replacement:

• Source a replacement turntable motor that is compatible with your microwave. 
• Disconnect your microwave from the power.
• Remove the lower panel of the microwave and disconnect the faulty turntable motor. 
• Put the new motor in its place, ensuring the wiring and other connections are correct. 
• Put your microwave back together and test to see if it’s still making too much noise during operation. 

Malfunctioning Magnetron

If you’ve ruled out other causes, the most likely culprit is a faulty magnetron. A magnetron is responsible for generating microwave radiation, and if it’s malfunctioning, it will make a loud, buzzing noise as it struggles to create microwaves. Another telltale sign of magnetron issues is if your microwave is not producing as much heat as usual or if it is producing a burning smell. 

NOTE: Only attempt to replace the magnetron if you are experienced with microwave repair and know how to safely discharge the capacitor. 

To replace the magnetron:

• Purchase a compatible replacement part before you begin
• Unplug your microwave from the power and discharge the capacitor. 
• Remove the faulty magnetron, ensuring you safely disconnect the wiring and remove the mounting screws. 
• Put the new magnetron in place, ensuring all wiring is connected properly
• Put your microwave back together and restore power. Try heating something to check that the problem is fixed. 

When To Call A Professional

It’s important to stay safe when doing DIY, so make sure you call in a professional if you feel out of your depth. Electrical repairs and issues with the magnetron require electrical experience, so if you have not completed these kinds of repairs before, make sure you seek professional assistance.