Technical Instructions: Installing or Replacing a Case fan in a PC

Technical Instructions: Installing or Replacing a Case fan in a PC


Installing or replacing a case fan in a computer is essential to ensure the device function properly. Working on the computer requires knowledge to identify the critical components of the PC. Further, to replace a faulty fan which has malfunctioned require in-depth knowledge and techniques functioning of the computer system. It essential to select the right fan that has maximum benefits for both computer hard and PC users. For instance, large fan emits high air flow compared to small sized fans. More so, they produce low noises as measured by decibels. The most important part of the case replacement requires the technician to follow steps which include; Identifying faulty fan, selecting a right fan, removing faulty or Installing new fan, mounting a fan, connecting the fan to a good fan header and Routing fan cables using zip ties. Further, some tools and equipment will be required to successfully work on the faulty case fan (Chiappetta, 2014). Tools such as Philips head screw, plastic holding clips, plastic friction clips, screws and fan controller are used to replace PC’s fan.

Product Description

A PC’s fan is a hardware component of the computer that keeps the entire computer cool by allowing circulation of air to and from the computer.  Unlike CPU and PSU that are mounted on their respective components, case fan can be attached almost anywhere to the front, side or back of the computer using screws (Chiappetta, 2014). It’s rare to find an intake fan towards the bottom of the computer. In most cases, case fan is installed at the front to pull cold air while the exhaust fan for expelling warm air is usually attached at the back or top of the case.

Choosing the correct size for fan replacement is critical since there is a wide range of sizes in the market for different computers. Cooling fans varies from small barrel types use to cool chips to large axial fans in power supplies.  According to Chiappetta (2014), most common fan sizes within a range of 70mm to 140mm while the other dimensions are as large as 230mm; thus becoming more popular. However, there is a new case of fans with a diameter of 120mm. The computer technicians recommend a fan with high airflow as the measure in cubic feet per minute (CFM). Additionally, best case fan should have low noise level measured in decibel (dBA). Furthermore, case fans vary in sizes, speed color, and blade shape. There are fans that come with inbuilt LED lights to give extra pizzazz. It’s worth noting that larger fans spin at the lower speed and still move more air without making many noises compared to small sized fans.













The PC fan is an essential part of the computer that helps to keep cool air flowing over other components. There multiple chips inside a typical PC that emit a lot of heat and require a cooling mechanism to remain in stable condition. When a computer is overheating, the user needs to replace the existing fan and install a new fan to help lower temperature. More so, checking and installing new fan makes PC quieter. According to Chiappetta (2014), faulty fans often emit strange grinding noises or distracting vibrations during its last death throws.

Operating Instructions

Tools and materials required to replace the faulty case fan

  1. Right fan with best features (A large fan with a diameter of 230mm)
  2. Philips head screwdriver- used to remove damaged or install a new case fan.
  3. Plastic holding clips- used for holding the fan in place
  4. Plastic friction clips-used for holding the fan in place
  5. Screws
  6. Fan controller- allows the computer to regulate fan’s speed
  7. Zip ties- ensure cable will not hit the fan as it spins







Steps for Installing or Replacing A New Case Fan In A PC

When replacing faulty Case fan in a PC, you need to be cautious by making sure the computer is powered off.

Step 1: Identifying faulty fan

The fan usually emits strange grinding noises and vibration during its last death throws. The P may not give a warning, but the fans silently come to a stop (Chiappetta, 2014). Checking fan case requires the technician to open the computer case and look around with a flashlight. You need to identify at least four fans: an exhaust fan, CPU cooling fan, intake fan, and Power Supply Unit cooling fan. Check if there are malfunctioning fans that have stopped and make sure the device is connected. If you discover the fan is connected but has failed to spin, it needs a replacement.

Step 2: Selecting Right Fan

There are various sizes and shapes of fans. Typical sizes range from 70mm to 140mm, the larger fans with a diameter of 230mm are more popular. It is essential to look for a fan with high flow and low noise levels.



















Step 3: Removing Faulty or Installing New Fan

When replacing a fan, the technician uses Philips head screwdriver to remove the old by unscrewing from the case and unplugging from MOLEX connection. The old screws can be reused in case the new fan lacks new screws.

Step 4: Mounting a Fan

You need to hold the fan up to the mounting position so that holes for screws are lined up with the holes in the case. More so, while holding the fan with one hand, make sure you use four screws to secure it in place with the other side (Chiappetta, 2014). On the other hand, in case you have plastic friction clips for attaching fan in place, un-snap the clips then detach the fan and connect new one to its location.













Step 5: Connecting Fan to Unused Fan Header

The header is carefully plugged to ensure proper connection. Note, four pin header will work with 3-pin header, but you can’t control the fan speed. Further, you can buy a fan controller which has additional benefits to the fan header. Another option involves the use of 3-pin/4-pin to MOLEX adapters connected to the fan right to the PSU.

Step 6: Route Fan Cables Using Zip Ties

The use of appropriate cable management ensures cable connected to the case are distant to prevent them from hitting the fans as it spins (Chiappetta, 2014). Ideally, when a spinning fan hit suspended cables causes a buzzing sound. Moreover, caution is critical to prevent wire coming into contact with fan stopping fan entirely due to damaged cable.




Chiappetta, M. (2014, July 28). How to install (or replace) a case fan. Retrieved from