The new Raspberry Pi 4 is significantly more powerful despite sharing the same diminutive form factor of its predecessors. With great performance, however, comes higher power consumption. The Raspberry Pi 4, therefore, generates much more heat than the older Pi models. Without active cooling, the Raspberry Pi 4 will thermal throttle even during moderate loads. Fortunately, this can be fixed by making or adding a fan to the official Raspberry Pi 4 case.
Note: there are plenty of third-party Raspberry Pi 4 cases with fan on the market. This tutorial is for those DIY enthusiasts who already own the official Raspberry Pi 4 case.
This is a fairly simple mod that doesn’t require any expensive tools that you wouldn’t already find in an average household. Some optional extras have been listed and marked accordingly. These are not absolutely essential, but they are nice to have. The extras may cost a bit more, but they will make your job easier while improving the aesthetics as well as performance of your Raspberry Pi 4.
Click on each item to find links to recommended products on the Amazon store. The different variants and subtle nuances of each of these tools and supplies will be explained in detail during the course of this guide.
- Raspberry Pi 4 Model B
- Official Raspberry Pi 4 Case
- Electric drill
- Hole saw kit or brad point drill bits
- Rotary tool
- Either a 30mm or 40mm case fan (5 volt, 2-pin versions)
- PVC dust filter for case fans (optional)
- Double-sided tape (thin)(optional)
- Hole punch set (optional)
- Raspberry Pi 4 copper heatsink kit (optional)
- Sandpaper (optional)
- Ruler and markers
- Safety glasses
- Isopropyl alcohol
Active Cooling the Official Pi 4 Case
Our first order of business is drilling a fan hole right above the processor.
1. Familiarize yourself with the case by fitting the Pi 4 inside the case. Determine the general area where the opening for the cooling can be drilled into the top half (white) of the case. Take extra care to stay clear of the GPIO pins, or the case will not close with the fan installed. The illustration below can be used as a general guideline, but you’re better served measuring twice and cutting once.
2. This is where you must decide the dimensions of the fan. You can choose between either a 30mm or 40mm fan. A larger 40mm fan pushes more air at a lower speed, which makes it quieter and more efficient. The smaller 30mm alternative spins faster and is noisier, but it is more compatible with other premium aluminum Raspberry Pi cases. It’s something worth considering for future upgrades.
The depth of the fan can vary between 6mm and 20mm for the scope of this mod. The blades of a thinner fan have relatively smaller surface area compared to the thicker alternative, which reduces cooling performance. A thicker fan can also house a more powerful motor. Just be sure to either avoid using a heatsink (not recommended) or installing one with a profile low enough to accommodate the thicker fan.
3. A hole saw set is the cleanest way to make the fan hole. You will need the 1-1/4-inch drill attachment to make an opening for the 30mm fan or the 1-1/2-inch one for the 40mm fan. If you don’t have access to the right-sized hole saw attachment, you can drill multiple holes using a large brad point drill bit to achieve a similar effect. However, that won’t allow for nearly the same rate of airflow as a proper fan-sized hole cut out using the hole saw.
4. Cut out a piece of cardboard or foam to fit the inside of the case as pictured below. This will prevent you from inadvertently drilling a hole in the bottom half of the chassis (red) after punching through the top half. It’s not feasible to drill the fan opening with the bottom half of the case removed since that makes it difficult to secure the case during drilling.
5. You can secure the case using anything ranging from duct tape to a bench vice. It is absolutely essential that you don’t use your hands to hold the case steady or leave it unsecured. The torque generated can make the drill or the case slip and cause serious injury. In the images below you can see my improvised method to secure the case firmly with some lumber and clamps.
6. Most modern drills have variable speed adjustment and an analogue trigger. Use these to prevent the drill from spinning at high speeds. Start the hole saw slowly and squeeze the trigger gently until the drill bit bites into the case. Once the drill bit is through, make sure the preceding hole saw bites smoothly into the case and does so dead straight. Don’t drill too fast, or the excess heat generated will warp the case. Use the fan as a template to mark and then drill four holes. These mounting holes will be used to attach the fan to the case.
7. We have to create one more opening on the long side of the case, right across from the audio/video and power ports. This opening will increase cooling efficiency by ensuring proper airflow in the otherwise airtight case. Be sure to keep the length of the opening smaller than the distance between the pair of adjacent mounting points on the inside.
You can either do this with a rotary tool such as a Dremel or by drilling a string of holes using a large brad point drill bit. Use 320-grit sandpaper to clean up the openings. You can skip this step if you aren’t keen on putting in the effort to smooth out the edges. Clean up both halves of the case.
8. (Optional) It is recommended to protect the Raspberry Pi 4 from dust ingress. Cut a fan-sized sheet from the PVC dust filter mesh. Use an appropriately-sized hole punch to make fan mounting holes. Use the supplied mounting hardware (nuts and bolts) to attach the fan to the top half of the case, with the dust filter sandwiched between the two.
9. Repeat the procedure for the other opening along the side of the chassis adjacent to the GPIO pins. It’s best to use a thin double-sided tape to stick the dust filter mesh to the case.
10. We are now clear to install the Raspberry Pi 4 in the bottom half of the case. Then comes the optional heatsink installation. Installing copper heatsinks on critical components not only improves cooling performance, but the added thermal mass also makes higher sustained overclocks possible. What’s the point of going to such trouble if you aren’t going to overclock it?
Most heatsinks come preinstalled with adhesive 3M tissue tape for mounting. You can identify it by its jet-black finish when you peel off the protective label (image below). Do not install the heatsinks bearing this black tissue tape. Quite ironically, the black adhesive tape is an insulator that will negatively affect cooling performance. Clean off the tissue tape thoroughly with isopropyl alcohol and use Arctic or 3M 8810 thermal adhesive pads instead. The Raspberry Pi 4 copper heatsink kit included in the item checklist earlier comes preinstalled with 3M 8810 thermal adhesive pads.
11. Install the heatsinks on the dies for the processor, RAM, and network as well as USB controllers. Apply moderate pressure on the heatsinks for 15 to 20 seconds in order to achieve proper wetting and adhesion of the thermal pads. Hook up the two-pin fan cable to the GPIO pins (red: 5v and black: ground) as shown in the pin-out diagram above while paying attention to polarity. (Red is positive and black is negative.)
Chilling Out with an Actively-Cooled SBC
Power up your Raspberry Pi 4 Model B, and you will notice that video playback is smoother. The processor will not overheat and throttle down during demanding applications, thereby improving real world performance. At stock settings, my Raspberry Pi 4 held steady below 50°C even under moderate loads. With the active cooling setup in place, I even managed to overclock my Pi 4 to an impressive 2GHz.
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