A custom liquid cooling loop costs roughly $600 to $1,000 in parts in 2026. That’s 3 to 5 times the price of a 360mm AIO. You’ll also change the coolant every 6 to 12 months, depending on the fluid, and strip the loop down for a full clean about every 24 months.

We think most buyers should start with an AIO. A custom loop mostly gets you quieter fans and a cooler GPU, so it only makes sense when you’ll notice those two things.

AIO or custom loop: what you are actually buying

An AIO is a sealed CPU cooler, while a custom loop is a set of separate parts that can cool the GPU too. The AIO arrives filled and closed, with the pump, block, tubing and radiator already joined. For a custom loop, you choose the CPU and GPU blocks, the pump and reservoir, the radiators, and the fittings and tubing. Then you cut, fit and fill them yourself.

Labor is the other big difference. ThermalStats estimates the install times below.

If it’s your first loop, save it for a free day so you don’t have to rush the fitting or filling.

Where a custom loop beats a 360mm AIO

A custom loop wins on noise and GPU temperatures. It won’t make your CPU much cooler than a good AIO, but it can run its fans slower and still keep up. A HardForum user compared a custom loop with a 280mm AIO, one size smaller than a 360mm AIO. The loop’s fans ran 400 RPM slower than the AIO’s, and CPU temperatures rose only 1.5°C. The loop still beat the AIO.

That’s a single community test, so don’t treat it as a rule. On the CPU side, noise is what you’re paying for.

The bigger gain is the GPU. An AIO only cools the CPU, so the graphics card still dumps its heat through its own fans. A full cover block sends that heat to the radiators instead, which makes a high-power card run cooler and quieter. If the CPU is the only part you want cooler, a 360mm AIO gets you almost all of the benefit for much less money.

ArsenalPC Verdict

Buy a 360mm AIO unless you’re cooling a high-wattage GPU and want quieter fans.

What a custom loop costs to buy

Most of that $600 to $1,000 goes to two parts: the pump/reservoir and the GPU block. A D5 pump/reservoir combo costs $170 to $300 at Corsair’s list prices. A May 2026 buyer’s guide prices an RTX 5090 full cover block at $275 to $425. For comparison, Tech Insider prices a complete 360mm AIO at $130 to $220.

Extras set most of the pump price. Above the base combo, the extra money pays for iCUE LINK control and, on the $299.99 model, an LCD screen. Custom PC called the $299 price “very expensive for a reservoir/pump combo unit.” TechPowerUp reviewed the original XD5 in 2019 at $154.99, so the basic pump has risen only $15 in seven years. We’d buy the plain combo and spend the savings on radiator area.

Some estimates come in lower. FormulaMod, a parts retailer, quotes $150 to $250 for a CPU-only loop and $400 to $700 for a full loop with premium parts. We’d still budget the higher range if your loop includes a GPU block. Parts lists also often leave out a few small costs:

• Drain valve: FormulaMod says a ball valve costs under $10. Without one, you have to undo fittings inside the case to drain the loop, and coolant can spill onto your hardware.
• Hub or controller: the $299.99 LCD combo needs an iCUE LINK System Hub, which Corsair sells separately.
• Spare coolant: you’ll need it for the first top-up after air bleeds out, and again at every refill.

How often a custom loop needs maintenance

Plan on a coolant change about every 12 months and a full teardown every 24 months. Corsair and FormulaMod both give the 12 month figure. EKWB says the pump itself needs no regular maintenance, but it still recommends a distilled water flush every year or so.

The refill is cheap. FormulaMod recommends distilled water below 5 µS/cm with an inhibitor or biocide such as Mayhems X1 or Feser One. It puts the cost at under $20 for a typical 1 to 2 liter loop. Your time costs more than the fluid. A ball valve drain keeps the job short.

The teardown takes much longer. FormulaMod says to inspect the microfin channels in the blocks, replace any discolored tubing and flush the radiators. Corsair notes that some loops run for years without trouble while others show problems within months. So change the coolant early if clear fluid turns cloudy or colored fluid fades.

Clear coolant means less work than pastel

Pastel and opaque coolants need changing every 6 months, twice as often as clear fluid. Particles suspended in the fluid give pastel its color. Over time they settle and clog the microfin channels in the blocks, so the 24 month teardown has more buildup to clean out.

Clear premixes and concentrates last the full 12 months. FormulaMod estimates they run 1 to 2°C warmer than distilled water, against 3 to 5°C for pastel. Those temperature figures are a retailer’s estimates, but the maintenance gap is clear. We’d fill with clear coolant and get the color from tinted tubing or lighting.

Keep aluminum out of a copper loop

Build the loop from copper and brass parts only. Mixing aluminum and copper causes galvanic corrosion, which eats away the aluminum and leaves deposits in the blocks. Corsair rates the XD5 combo for copper and brass only, so one aluminum radiator puts your loop outside the pump’s rating.

Coolant makers warn against aluminum too. PrimoChill’s ICE coolant text calls aluminum “strongly discouraged” and says using it voids the fluid warranty.

A single-brand loop carries the least risk. Corsair says a loop built only from Hydro X parts and its XL coolant, which is 89% pure water, generally has no compatibility issues because Corsair tests those parts together. If you mix brands, check the metal listing on every radiator and fitting before you buy.

What happens when a cooling vendor stumbles

Spare parts can stop arriving. EKWB’s 2024 to 2025 crisis left about €300,000 in prepaid orders unfulfilled, according to EK’s own transparency site. That total peaked on 26 June 2025 and covered about 1,100 customer records.

The trouble became public in early 2024, when Igor’s Lab reported unpaid EKWB invoices. GamersNexus, Tom’s Hardware, KitGuru and PC Gamer published investigations between April 2024 and February 2025. The Slovenian Labour Inspectorate then opened its own probe. EK sent orders placed after 10 April 2025 through LM TEK’s shop.

The older orders are clearing slowly. EK’s dashboard showed 31 of 543 legacy orders resolved, which is 6%. If you own an EK loop, a replacement block or pump top may not arrive when you need it.

A loop can outlast its vendor, so we’d build around standard parts. D5 pumps, G1/4 fittings and copper radiators come from several makers, so another brand’s part can replace a failed one. The GPU block fits only one card model. Buy that block from a vendor with stable support and spares in stock.

Is a custom loop worth it for your build?

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A custom loop is worth it for a high-wattage GPU build where you want quiet operation and you’ll do the yearly coolant service. If you only need to cool the CPU, a 360mm AIO is the better value. We’d point most first-time buyers to one. Four things decide it:

• GPU wattage: a 5090-class card is where a full cover block makes the clearest difference.
• Noise tolerance: the loop’s CPU-side gain is slower fans, so pay for it only if fan noise bothers you.
• Yearly service: if you won’t drain and refill every 12 months, buy the AIO.
• Looks: hardline tubing and a visible reservoir are reasons in their own right.

If all four point to a loop and you’d rather skip the build, ArsenalPC builds custom loops in Willoughby, Ohio.