Let’s not beat around the bush: As with anything PC-related, there’s always going to be some risk involved, especially when working with liquid. Whether that’s not installing a fitting correctly, not using the correct length of tube, or forgetting to plug a hole, the risk is there. You’re always going to hear horror stories of liquid cooling going wrong, or loops suffering leaks after prolonged periods of use. The reality is, these events are quite rare. As long as you take your time, follow the instructions, and do things correctly, it’s unlikely you’ll ever encounter these issues, any more than you would encounter a dead AIO.
And, of course, there are precautions you can take to reduce the chance of a mishap. Things such as making sure your power supply fan is facing down, priming your loop with everything bar the pumps disconnected, making sure that each fitting is secure using the included Allen wrench, using the correct length of tubing, and not cutting corners are imperative. It’s also advisable that after you’ve first built and primed your loop, you run the loop for a full day, with everything disconnected, to check if there are any leaks, using paper towels as indicators.
Even we’ve had our fair share of liquid cooling mishaps and leaks in the past, yet not one crucial piece of hardware has died because of it. Our ITX liquidcooled build back in July 2016 suffered a failed o-ring on one of the angled fittings atop the Fury X GPU, leaking down off the block and on to the PSU (which, fortunately, had the fan facing down), likely due to too much pressure and not enough tube. And even in our latest build, we had to drain the loop and reseat the memory.
One of the biggest concerns we hear is the fear of mounting the blocks incorrectly. Ironically, this is the safest part of the whole job. The blocks themselves are completely sealed units—simply put, no coolant ever touches the component. Take a graphics card block, for instance. The block makes contact with the GPU, the memory, and the VRMs (usually with thermal paste for the GPU, and thermal pads for everything else). Coolant then flows around the block, drawing heat out from the nickel, copper, or, in this case, aluminum, through pre-milled channels, and out toward the radiators, where it’s cooled.
The biggest risk comes from removing the stock cooler from the card; most liquid cooling manufacturers include instructions on how to remove the stock coolers. Take your time, use the correct tools, and you’ll be fine.