8 things you need to build your own custom PC liquid cooler

Installing an all-in-one (AIO) liquid cooler for your CPU is one thing, but it’s a whole different ball game to set up your own loop. This involves many parts as we’ll be building everything from scratch. We’ll need a radiator, reservoir, water block, pump, and more to cool your CPU and GPU using a custom liquid cooling solution. Depending on what you plan on cooling and how much budget you have assigned to this project, it can cost as little as $200 or as much as an entire PC build. The end result, however, is incredible.

8

Radiator

Handling the transfer of heat

The radiator transfers heat from the fluid running through your loop to the internal air circulating through the PC case. It looks the same as what you’d find attached to an AIO liquid kit and works identically. Liquid goes in one end, passes through the radiator, radiates heat away via the fin stack, and comes out the other end. I recommend having 120mm as an absolute minimum when planning out a custom loop. Then for each component added to the loop, be it a CPU, GPU, or both, you should add a 240mm each.

For cooling just the CPU, you can get away with a 240mm radiator, though I’d suggest a 360mm for extra headroom. Adding a GPU to the mix should take you to at least 480mm, especially with more advanced graphics cards that produce more waste heat. You can always mix it up with two 240mm radiators instead of one giant tower, which can prove useful when working with smaller cases, or split up the loop into two. One for the CPU and the other for the GPU, though this would require doubling all the parts.

7

Reservoir

Storing excess fluid

The reservoir inside a liquid-cooled PC stores liquid, much like a natural lake or man-made reservoir would. Why would you want more fluid than required? It’s a good question since AIO kits don’t typically have much excess fluid, but these are sealed loops and are completely enclosed with multiple layers, and thus evaporation should be minimal — it is possible to get fluid with an AIO kit that can be used to top-up the loop should a need arise.

For a custom liquid cooling loop, the reservoir can be a standard standalone tower, one attached atop the pump, or as a distribution plate. While it’s not required, I recommend having a decent amount of fluid running through the system and available should a small leak develop or some of your liquid evaporate. This would limit the number of times a top-up would be required, keeping the loop sealed.

6

Water block

Connecting your CPU and GPU to the loop

The most vital part of your liquid cooling loop is the water block. It’s what connects your loop to the CPU and GPU. Without this, or if it’s incorrectly installed, you’ll have some serious issues when attempting to boot the system and play some games. Water blocks come in all shapes and sizes, some with RGB lighting, and others with fancy designs to match specific themes. Depending on your CPU socket and personal preference, you can go with a budget-friendly block or one with premium features and thermal performance.

It’s worth paying close attention to CPU and GPU support when shopping around since not all blocks will support every socket or GPU. Even a water block designed for the RX 7900 XTX may not work with the RX 7900 XT and vice versa.

5

Pump

The heart of your loop

The pump is a basic device. It’s powered by your PC to pump liquid through the loop. You can purchase them as part of a kit with an integrated reservoir or as standalone units. Always ensure to never place the pump at the highest part of the loop as this is where air within the system will likely surface and remain. So long as a part of the tubing or the radiator is higher, you’re good to go.

4

Tubing

Flexible, hard, and everything in between

Tubing connects everything. Think of it as the veins and arteries of your liquid cooling loop. Whether you use soft or hard tubing depends on what look you’re going for and how much time you wish to invest in creating this open-loop liquid cooler. Soft tubing can be easier to work with, but hard tubing creates a cleaner look with hard turns and various styles that cannot be achieved with softer materials like PVC. For hard tubing, you have the option of glass, Glycol Polyethylene Terephthalate (PETG), or acrylic.

3

Fittings

The choice is yours

The fittings required for your loop depend on the tubing material and size. Hard tube styles such as acrylic and glass will require push-in or HD compression fittings. These are usually made from silver or nickel, but you should be fine with copper equivalents. Push-in fittings are different than barbs used for soft tubing because they use two o-rings to create an air-tight seal once the tube has been pushed into the fitting. Hard tube fittings are usually listed with only the outer diameter (OD), which needs to match the OD for hard tubing. The most common sizes are 1/2 inch (13 mm) and 5/8 inch (16 mm).

Soft tube fittings are slightly different in that you need to apply compression onto the tube and create a seal with a flexible surface. We can either use a barb, which simply allows the tubing to wrap around a point with a clamp, or a compression barb which is similar to a standard barb but has a locking ring. I recommend the latter for all parts of your system aside from a fill line, which can use a simple barb.

2

Fluid

All the colors!

It would be difficult to take waste heat from your CPU and GPU, transfer it through the system, and out via the radiator without some form of liquid. Distilled (or deionized) water is great for flushing the system through and testing to ensure your loop has no issues, but if we relied on just this water we’d have some bacteria flying through the PC. That’s where some additives and inhibitors come into play, combating growth and corrosion, since we’re still working with metal.

You can use some distilled water and some inhibitors or go all-out with some fancy-colored fluids. Brands such as Mayhems and Corsair create some excellent products and I’m a huge fan of the XT1 range.

Shape and bend at will

Depending on how you plan to go about building your custom liquid cooling loop, you’ll need a few tools. First, you’ll need a way to cut tubing. A heat gun and bending apparatus will be required for working with hard materials — a filer will also be necessary when cutting harder tubing. Finally, a funnel is a must for filling up the system between flushes. That’s it!

Building a custom liquid cooling loop is rewarding

Although a daunting and difficult task, putting together your very own liquid cooling loop is incredibly rewarding. The learning curve may seem steep at first, but once you get used to cutting, bending, and shaping tubing, working with fittings, and trusting the seals will hold, you’ll be an expert in no time. The result is a truly unique system with custom lighting, colored fluids, tubing, and fixtures. Depending on your PC theme, custom liquid cooling can take your system up to 11.

One thing to bear in mind is the materials that make the different parts of your loop. Copper radiators and water blocks with nickel fittings are perfectly fine and won’t cause any trouble. Copper and nickel are usually okay to use together, but when you throw aluminum or silver into the mix, you run the risk of encountering issues with galvanic corrosion. Inhibitors in the fluids can help mitigate this but over time, you’ll need to keep a close eye on the loop to make sure it’s not corroding away.