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How to clean your PC's CPU water blocks

The CPU water block handles much of the work in a water loop, including the transferring of heat between the processor and the fluid passing through the block. Due to the nature of using water, even in a well-maintained loop, you're bound to encounter at least some form of growth inside the block. Luckily, it's usually a simple process to take the CPU water block apart, clean it, and seal everything back together again.

It's important to stay on top of your water block cleaning schedule to ensure the component is running at maximum efficiency, and you should keep the loop in general completely clear of all growth. Replacing piping and a radiator but keeping the same old water block may contaminate the new parts if you don't scrub it clean. In this guide, I'll be using a Supremecy MX Evo water block (opens in new tab) (around $82.99) from EK, sporting a copper base and plexi cover.

Cleaning the CPU water block

CPU Block

The most important tool you will need is a toothbrush. Think of the block as teeth that need a good session of brushing after a night out. While each block may be a little different, these steps should still work:

  1. Take apart the CPU water block by removing the screws on the base.

CPU Block

  1. Check each part for corrosion.

CPU Block

  1. Fill a bowl with warm water.
  2. Add white vinegar for copper and soap for nickel-plated blocks.
  3. Submerge the metal parts and allow them to soak. (The plastic or acrylic tops require soapy water.)
  4. Scrub the fins and other parts with the toothbrush to remove gunk.
  5. Rinse everything through with distilled water.

And you're done! Just be sure to remember to run some distilled water through the loop once re-assembled before throwing in pastel fluid. This is why it's important to stay on top of keeping growth and gunk at bay, particularly in the water blocks. This restricts the flow of water, especially between the fins, where there is less than a single millimeter of spacing. It takes only five minutes and can make a big difference.

Material consideration

CPU Block

CPU Block (Image credit: Rich Edmond / Windows Central)

Not one single method of cleaning will work on every water block. It entirely depends on what kind of material the block is made from. Here are general rules when it comes to cleaning block bases and the various tops:

  • Acrylic — Good ol' soapy water. Do not use any form of alcohol or abrasive substance.
  • Acetal — Just like Acrylic tops, cleaning Acetal with soapy water is recommended.
  • Copper — Use slightly acidic cleaning elements like white vinegar or even Coca-Cola to clean the base.
  • Nickel — Use only warm water for nickel-plated copper, followed by non-abrasive metal polish. Be sure to rinse with distilled water afterward.

More on PC water cooling

Rich Edmonds
Rich Edmonds

Rich Edmonds is Senior Editor of PC hardware at Windows Central, covering everything related to PC components and NAS. He's been involved in technology for more than a decade and knows a thing or two about the magic inside a PC chassis. You can follow him over on Twitter at @RichEdmonds.

3 Comments
  • I've always been of the belief that electronics and liquid don't mix and so won't put a watercooler in my £1200 PC. Personal choice but I just have this niggling feeling that when something goes wrong it will be an expensive repair. I'll stick to using a good air cooler, I don't overclock anyway
  • So I guess you do your laundry by hands?? Washingmachines are also electronics mixed with water... 😉
  • What about closed-loop, AIO systems? I have an NZXT Kraken X62 AIO CPU system, and I have two GeForce® GTX 1080 Xtreme Gaming WATERFORCE cards. I can't imagine those are made to open and clean as described in the article, and would likely void any warranty. Are these AIO closed systems exempt from the "goo" build-up? Thanks for your replies, because I really don't know.