CPU Fan Twitching Not Spinning? Here’s Why

CPU fans are crucial in preventing your PC from overheating. If your CPU fan doesn’t work properly, your processor will overheat, and the rest of your computer will be negatively affected. Fixing a twitching or otherwise malfunctioning CPU fan is essential for PC longevity.

Your CPU fan is twitching and not spinning because there’s too much debris buildup, the fan is broken, or the power supply or motherboard isn’t working. Additional causes include BIOS errors, electrical issues, and inadequate bearing lubrication.

Throughout this post, I’ll explain the possible reasons your CPU fan is twitching and what you can do to fix them. I’ll also discuss a handful of preventative tips along the way.

CPU Fan Twitching Not Spinning?

CPU Fan twitching not spinning?

There’s Excessive Debris On The CPU Fan 

All computer fans eventually get covered in dust and grime. They’re constantly spinning, which attracts tons of debris that can get stuck in the blades and bearings.

If you don’t remove the debris, the fan will lock and be unable to move. The fans will start twitching, and then they’ll stop working altogether.

The good news is that this is one of the easiest issues to fix if you catch it before it damages the CPU or the fan.

How To Clean The CPU Fan

Here’s how you can remove the debris buildup from your CPU fan to stop it from twitching:

  1. Turn off the computer and remove the cover plate from the CPU fan.
  2. Use a can of compressed air to remove dust from the blades and the base of the fan.
  3. Remove debris from hard-to-reach places with a Q-tip or a pipe cleaner.
  4. Spray rubbing alcohol on a microfiber cloth and wipe the blades to prevent grime and debris from sticking to the fan.

Once you’re done, cover the CPU fan and turn it on. If it still doesn’t work, head to the next suggestion.

The CPU Fan Is Broken

Once the fan is broken, all you can do is replace it. Broken CPU fans are caused by many problems, most of which relate to gradual wear and tear. Below, I’ll list a handful of reasons you might have to replace your broken CPU fan:

  • Your fan is beyond the manufacturer’s warranty and doesn’t work anymore.
  • The CPU fan is past the manufacturer’s suggested longevity.
  • Blades or bearings are broken on the CPU fan.
  • The motor is fried and can’t be repaired.

How To Replace A Broken Fan

Your only solution for a broken fan is to replace it. Follow these instructions to swap out your CPU fan:

  1. Turn off your computer. 
  2. Remove the wires and the side panel to expose the processor.
  3. Remove the retaining bolt or bracket from the CPU fan. 
  4. Remove the fan and clean the thermal paste off of it.
  5. Apply thermal paste to the plate on the bottom of the new CPU fan and press it against the CPU.
  6. Slide the bracket or bolt through the fan to lock it in place.
  7. Connect the new CPU fan to the motherboard via the provided cable or with the old one if it’s still attached to the motherboard.

For more information, review this helpful YouTube video about replacing CPU fans:

YouTube video

The Power Supply Is Faulty 

A faulty power supply is one of the most common reasons a CPU fan twitches without spinning completely. 

The power supply is also responsible for operating many other components in your PC. If anything else isn’t working like it should (in addition to the twitching CPU fan), there’s a good chance something’s wrong with the power supply.

When the power supply is the cause, the computer often won’t post or start up as the motherboard won’t function properly.

Before replacing either part, check the connection between the power cable and the power supply.

How To Deal With A Faulty Power Supply

Here’s how to replace a broken power supply and fix your twitchy CPU fan. 

  1. Turn off the computer and unplug it from the wall. 
  2. Remove the computer’s side panel to expose the motherboard. 
  3. Disconnect the power supply cables from the motherboard. They’re usually tied together, so you should remove them by unclipping the main wire.
  4. Remove the wires connecting the power supply to the hard drive(s) and set them aside, ready for the new power supply.
  5. Remove the retaining screws and pull the power supply out of the computer. 
  6. Slide the new power supply unit into place.
  7. Connect the hard drive and motherboard wires to the new power supply and secure the retaining screws to the power supply and the PC.

When you’re done, plug the computer in, turn it on, and check your work.

There’s Insufficient Bearing Lubrication

All bearings need lubrication, including CPU fan bearings. Not having enough lubricant on a CPU fan bearing can cause the fan to screech or run dry, making it twitch. They can also make the CPU and PC overheat.

One of the most common signs of a dry bearing is when it feels hot around the fan. Warm fans are normal, but metal-on-metal friction makes the bearings extremely hot.

Some Advice: If a fan relies on a sleeve bearing, throw it away and replace it with a new ball bearing or other low friction bearing style fan. For a CPU fan, this may involve replacing the whole cooler itself.

How To Lubricate CPU Fan Bearings

Lubricating your CPU fan can make a huge difference, so let’s break down the step-by-step process below.

  1. Turn off the computer. 
  2. Remove the CPU fan from the PC and lay it on its face, preferably on a paper towel.
  3. Remove the sticker from the center of the CPU fan to reveal the cover.
  4. Take the cover off the center of the CPU fan with a flathead screwdriver or knife.
  5. Remove the small retaining clip so you can disassemble the fan. Be careful not to damage it. Removing the retaining clip can test your patience, so stay calm and take your time.
  6. Clean the bearing area as best as possible, preferably with rubbing alcohol.
  7. Place two drops of all-purpose oil on the bearing, then reassemble the fan.
  8. Place the cap over the bearing area and replace the sticker with a small piece of tape to seal the CPU fan. Another way is to reglue the old sticker to try and maintain its originality.

When you’re done, mount the fan back in the PC, then turn it on.

The CPU Fan Wires Are Damaged

CPU fans have several wires going to the motherboard. They often use a multiport clip that connects to the motherboard without soldering or crimping each wire.

If any wires are bent, stripped, or exposed to copper, they won’t work properly. This incorrect layout could cause the CPU fan to twitch because there’s no steady power supply.

How To Repair Damaged Wires

Damaged CPU fan wires are relatively uncommon (unless you mishandle the PC). However, you can use these suggestions to inspect and replace the wires as necessary:

  • Replace any of the wires if the copper is exposed or if the wire is bent beyond repair.
  • Disconnect each wire connected to the CPU fan and check if the clips are cracked or loose. If they are, replace them.
  • Push and secure each wire clip on the motherboard and the CPU fan to ensure they’re not wiggling or shorting the electrical current.

Note: If you replace the CPU fan wires, contact the manufacturer to get the part number. You can also check the part diagram to ensure you’re doing the right thing. Using the wrong wires will prevent it from working.

Your Computer Has BIOS Errors

Check the PC BIOS to know how your CPU fans are running. For example, if they’re twitching, they should be at 0 RPMs. If the RPMs look normal in the BIOS, there may be something wrong with the CPU fan’s wires, the motherboard, or the BIOS.

There are many solutions to these issues, so let’s dive into everything you need to know below.

How To Correct BIOS Errors

Try this method to look for BIOS errors:

  1. Access your computer’s BIOS settings. You can access most of them through the startup menu.
  2. Click on the cooling or circulation menu, then look for the CPU fan’s speed and the PC’s temperature.
  3. Increase the fan’s speed and check if your CPU starts to work. If it doesn’t, the fan is likely damaged and needs to be replaced.
  4. If the fan speed increases, your computer might have malware that affects the BIOS and alters the CPU fan speed.

BIOS errors are relatively uncommon, especially if you update your operating system and computer. I recommend manually checking for updates in your computer’s settings menu every month or so.

Your Computer’s Motherboard Is Malfunctioning 

The motherboard is responsible for operating all the parts in your PC apart from the power supply. If the motherboard isn’t working properly, you’ll notice many issues. These errors could range from twitching CPU fans to random restarts and more.

Most computer motherboards last a long time, but improper air circulation, electrical wiring issues, and old parts can take a toll on the PC’s motherboard. Once the motherboard stops working, the CPU fan will twitch and fail.

You will often find the computer won’t boot or start-up when the motherboard is the cause of the problem.

How To Replace The Motherboard

Getting a new motherboard is a long, detailed process. I advise checking the power supply, the CPU fan, and all other parts before replacing the motherboard.

If you find that replacing the motherboard is your only available solution, follow these instructions:

  1. Turn off your computer, disconnect the power cable, and remove the side panel.
  2. Lay your computer on its side and take a picture of all the wires going into the motherboard. You’ll need this as a reference for the new motherboard.
  3. Remove the motherboard from the PC, ensuring you disconnect each attached wire.
  4. Transfer all the onboard components, like the CPU, RAM, and SSDs, to the new motherboard.
  5. Transfer and install the CPU cooler to the new motherboard, or install a new one onto it.
  6. Mount the new motherboard in the PC, then connect each of the wires according to the previously mentioned wire picture or the wiring diagram if your computer has one.
  7. Connect the power cable, replace the side panel, and turn on the computer.

Your CPU Is Overheating 

If your CPU fan isn’t the right size or the CPU runs hot, it’ll wear down the bearing, motor, and wires on the fan. This ends up ruining the fan, directly affecting your processor’s performance.

Additional causes of an overheated CPU include:

  • Setting your games and other programs to the highest settings when your CPU has limited capabilities. 
  • Running your computer with the side panel off. It may look great, but it causes all sorts of problems. 
  • Not using thermal paste on anything connected to the CPU. 
  • The CPU Cooler isn’t installed correctly.

How To Fix An Overheating CPU

Consider these suggestions to stop your CPU from overheating and damaging its fan:

  • Reduce your program settings to relieve some of the strain on your CPU.
  • Keep the side panel on your computer to keep dust and debris out. This’ll keep the fan from getting jammed.
  • When mounting the cooler, apply a pea-sized amount of thermal paste on the CPU.
  • Undo any overclocking or voltage adjustments. The easiest way is to reset the BIOS back to default.
  • Ensure that the CPU cooler is correctly mounted and properly contacts the surface.

Don’t forget to contact the manufacturer regarding warranty issues if you want to replace the CPU before the warranty period expires.

You’re Using a Low-Quality Extension Cable With Your PC

I typically avoid using extension cables for PCs because they can get overloaded fairly easily. Direct wall outlet connections are always the best and most reliable solution. 

Low-quality PC extension cables can affect the power quality getting to your CPU, preventing the CPU fan from spinning properly. It might work sometimes, but other times it’ll twitch uncontrollably.

How To Avoid Extension Cable Problems

So, how can you prevent extension cables from ruining or reducing your CPU fan’s capabilities? Try some of these recommendations:

  • Connect your computer directly to a wall outlet.
  • Never exceed the extension cable’s electrical capacity to prevent it from overheating or tripping the breaker.
  • If you’re determined to use an extension cable, ensure it has a built-in surge protector.
  • Check the wall outlet’s amp limit (and don’t exceed it with too many cables).

Extension cables are hard to avoid when you have a PC, a monitor, and other office equipment plugged into the same outlet.

Final Thoughts

Although CPU fans last several years, annual maintenance is very important. Not only will it prevent your CPU fan from breaking, but it’ll also help you get the most out of your processor.

A little cleaning can make a difference and ensure proper air intake filter maintenance.