I mentioned the other day that the water-cooling unit in my main PC had failed, and I told the tale of replacing it. What I didn't do was go one step further and examine the ailing Corsair H60 to see what caused it to stop being effective. Instead, I sat it aside and moved on—until last night, when a friend of mine who reads the site visited Damage Labs, saw the cooler in question, and encouraged me to do some follow up.
At his prompting, I grabbed a pair of wire cutters and snipped open one of the hoses on the H60. What came out was a small volume of coolant—not enough to fill the entire cooling loop, but more than nothing. Mixed in with the green-tinted coolant were dark green chunks of apparently coagulated coolant. Those chunks were thick enough that I don't see how coolant could have flowed properly through the system with them present.
So was it a pump failure or a coolant leak? Inconclusive. Apparently the loop wasn't sealed perfectly, since some of the coolant dried out like that. Given the chunky state of the liquid, it seems quite possible that the pump might have failed, too. Who knows?
What I do know is that the H60 wasn't effective any longer, and replacing it with a tower cooler made a world of difference.