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How To Know if Your Hotend Fan Is Working Properly

Identify hotend fan issues: Learn to assess your 3D printer's hotend fan performance, ensuring optimal cooling and preventing print problems.

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A hotend fan performs the crucial function of keeping the hotend cool during printing to prevent premature melting. However, while important, its functionality goes unnoticed until it becomes a big issue. But is it possible to determine if your hotend fan is working correctly, and how?

To know if your hotend fan is working properly, determine if it spins automatically when the temperature reaches 50°C (122°F). A well-functioning fan also turns when connected to a power source, prevents heat creep, and pushes cool air inside to maintain optimal conditions.

Since your hotend fan prevents heat creep and keeps your hotend functioning properly, it is vital to ensure its functioning properly. You should know what to look out for and when. This article will discuss everything you need to know to determine if your hotend fan is working properly. 

1. The Hotend Fan Spins When Temperature Reaches 50° C

One of the key indications that your hotend fan is working is that it begins to spin when the temperature reaches 50°C (122°F) automatically. 

The primary function of the hotend cooling fan is to cool the top part of the hotend. 

This ventilation protects the cold areas, like your heat sink, from the heat transferred to the heater block and nozzle, preventing them from getting too hot during the printing process. 

By design, the hotend fan should start spinning when the temperature reading of the hotend reaches 50°C (122°F).

Once it reaches this temperature, the hotend fan should continue spinning throughout the rest of the printing process. A malfunction in this fan can negatively affect heat transfer and cause the nozzle to jam after the first initial layers.

How To Resolve This Problem

If your hotend fan does not automatically spin when your hotend reaches 50°C (122°F), this may indicate a problem with your wiring. Alternatively, this may mean that your fan has malfunctioned and needs replacement. 

To check for connection issues, follow the steps below: 

  1. Turn off the 3D printer.
  2. Examine the wired connection to make sure the fan is connected correctly.
  3. Look out for any signs of physical damage.
  4. Peer into the hotend to search for debris and clogs. If you find any, you need to remove them with tweezers. 

If all the connections are okay, test whether the hotend fan works correctly by following the approach discussed below.

2. The Fan Works When Connected to a Power Source

After troubleshooting for connection errors, the next step is determining if the hotend fan has a mechanical issue. To do this, you need to connect the fan to an external power source and check whether it spins. 

A properly functioning fan should spin once connected to an external power source with a matching voltage. To test your hotend fan, follow the simple steps below:

  1. Turn off the printer.
  2. Unplug the fan from the electronics board.
  3. Test that the fan works by connecting it to an external 12V DC power source.

If the fan spins when connected to an external power source, the issue likely lies in the connections and wiring. 

It is also possible that your fan is not working on your 3D printer due to faults in the electronic wiring. Therefore, you must check that all the electronic wiring is connected correctly and look for any melting or damage to each cable.

How To Resolve a Malfunctioning Fan Issue

If you determine that the hotend fan is not working once you connect it to an external power source, you should replace the entire fan. The good news is that the hotend fan is easy to replace.

Creality Experts also recommend replacing the fan if it is weak or damaged. Depending on your 3D printer, I recommend getting the Creality Ender 3 Original Fan (available on as a replacement. This hotend fan is compatible with Ender 3 and Ender 3 Pro 3D Printer models. 

It boasts a maximum rotational speed of 5,500 rpm to keep up with cooling demands. This cooling fan also features a 30-decibel rating for silent operation. 

Alternatively, the Creality 3D Original Hotend Fan (available on is also an excellent option. Compatible with Ender 3/3 Pro/3S/ 3 V2/3, Max Ender 5/5 Pro, and 5 Plus 3D Printers, this hotend fan presents a versatile cooling solution. It is also quick and straightforward to install and replace. 

3. You Are Not Experiencing Clogs or Heat Creep

As mentioned above, sometimes your nozzle can stop working after the first layers of the print process. This phenomenon is known as heat creep. 

Heat creep is just what it sounds like. It occurs when the heat from the heater block creeps up the hotend, warming up your filament before it hits the nozzle. This creep will result in clogs, damage to the hotend, and potential damage to your extruder. 

One of the main tell-tale signs of heat creep is when the nozzle stops extruding the filament after the initial layers. If this happens, your printer will likely continue printing, but no filament will come out. 

However, heat creep can also manifest in other different ways, as follows:

If this happens, then there is a problem with the hotend fan. However, if the filament continues to extrude from the nozzle without errors throughout the printing process, the hotend fan is working correctly. 

How To Resolve Heat Creep

One solution to prevent heat creep is to lower the hotend temperature. Lowering the hotend temperature reduces the heat in the heat block. 

However, this fix will only work for you if your temperature settings are incorrect for your filament, and if your fan is malfunctioning, it won’t help that much. 

Alternatively, you can resolve this problem by increasing the fan speed. 

If the fan speed does not increase when you manually adjust it or reset the rate in your slicer settings, you may be dealing with an electrical or mechanical problem with the fan. If that’s the case, you’ll likely need to replace either a wire or the fan. 

4. The Extruder Motors Are Silent and Run Smoothly

Heat creep can also result in the extruder motor producing a clicking or ticking sound; thus, these clogs might be a symptom of a faulty hotend fan. 

Therefore, you can know if your hotend fan is working correctly by looking out for any ticking or clicking sounds from the extruder motor. 

This clicking or ticking sound occurs if there’s a clog somewhere in your extruder. Because of the clogging, the extruder motor will not be able to push the filament down the hotend properly. 

When this clicking and ticking sound is associated with nozzle jamming after the initial layers, you may have a malfunctioning hotend fan on your hands. 

How To Resolve Clogging Issues Due to Heat Creep

It is crucial to remove clogs as soon as you notice them. Clogs can put excess stress on the stepper motors in your 3D printers, wearing them out more quickly. 

So, if you suspect you have a clog, attempt to unload your filament spool. 

If the filament comes out, investigate the nozzle, Bowden tube if you have one, and extruder gears. Look for anything causing a jam and remove it with a needle or tweezers. 

If the filament does not come out, set your printer to purge the hotend. Then, try unloading the filament again. This purge process should ensure that any excess molten filament escapes the hotend, unblocking the nozzle and extruder. 

Once you remove the clog, examine your cooling fan to ensure it is properly connected. Run a short test print to see if your printer is functioning well again. 

5. Your Fan Draws Cool Air Towards The Hotend

You can also determine whether your hotend fan is working properly by examining how it is mounted and assessing the airflow direction. 

One of the most common mistakes when installing a hotend fan is mounting it backward. When the hotend fan is mounted backward, it will push the air outside instead of inside. Consequently, it will fail to keep the cold areas cool, and your printing process will be compromised. 

How To Ensure Proper Airflow Direction 

One of the common indications that the fan is mounted properly is that you will not see the sticker on the fan. In essence, the sticker on your hotend fan should always face the direction of the hotend. 

The experts at Slice Engineering also recommend ensuring that one fan blows towards the hotend while the other blows air outside if you use a dual-extension setup.

Ensure the fan is pulling the air inside, not expelling it outside. 

6. The Fan Speed Is Easy To Adjust 

The 3D Printing process requires great precision, affecting the final product’s quality. Therefore, it is crucial to assess the fan speed to ensure that the hotend fan is spinning quickly enough to maintain optimal temperature conditions. 

How To Adjust the Hotend Fan Speed

You can determine the hotend fan speed from the LCD menu on your printer. To do so, follow these simple steps: 

  1. Access the LCD menu on your 3D printer during printing.
  2. Select Support from this menu.
  3. Select Extruder Info, and then click on Fan Speed.

Watch the video below for more on how to determine and set the fan speed: 

The recommended fan speed for the hotend fan is between 4,000 and 4,400 RPM. You can decide if your hotend fan is working correctly by checking the fan speed parameters from the LCD. 

While at it, check the temperature presets to ensure that you have set the hotend fan to turn on automatically once it reaches 50°C (122°F).

7. Your Hotend Fan is Very Quiet

A properly functioning hotend fan should not make a lot of noise. One of the common complaints regarding the hotend fan is that it gets loud once you start the printer. 

Some users have also complained of high-pitched noises when starting their Printers, which could indicate a failing fan blade or bearing. 

This issue may also indicate dust and debris accumulation inside the fan housing, resulting in loud noises. 

How To Clean Your Hotend Fan

To resolve this problem, it is essential to check your fan and look out for any signs of damage. 

Once you have established that there is no damage, the next step is to clean the fan to remove any dust or debris and then lubricate the fan. I recommend using a vacuum cleaner or compressed air to remove dust and debris. 

For a simple 3D printer cleaning solution, I recommend the Comobelief Compressed Air Duster (available on This compressed air duster features three-speed settings to remove stubborn debris. This wireless air duster is also repeatedly rechargeable and easy to clean for hassle-free maintenance. 

The experts at BCN3D recommend cleaning the hotend fan at least once every 300 printing hours. 

Watch the video below for other handy tricks to solve a noisy hotend fan problem.

8. Your 3D Prints Are Accurate and Precise

Another sign that your hotend fan is not working properly is the final product is poor in quality. While most problems associated with hotend fans occur due to low speeds, high speeds can also negatively impact the output. 

High print speeds result in rapid cooling, stringing, and in some cases, the formation of small blobs on your print or nozzle. Ideally, your final product should feature smooth details, lines, and shapes. 

High fan speeds can also result in warping or deformed results because the cooling process takes place too quickly. Other signs that your cooling rate may be too high include the following: 

  • Poor structure, shape, and easily-damaged end products
  • Failure of successive layers to bind together as a result of rapid cooling
  • Final products are fragile

As with the case of low fan speeds, you need to adjust the fan speed settings to resolve this issue.


While most people overlook the proper functioning of the hotend fan before it malfunctions, this article has made it easy. Ideally, you will know that your hotend fan is working properly when it starts spinning when the temperature reaches 50°C (122°F). 

Your fan should continue spinning until the process is complete. If you notice loud noises, issues with clogging, slow speeds of no movement, and movement of air outwards and not inside, your fan is not working properly.

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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.