H115i Pump not working?

I built my PC 7 months ago and have been using it daily with no issues. However, when starting up my PC on 8/7/20, the pump begins to make a strange noise which increases with time as the cooling system (H115i) tries to cool the increasing temperature of the CPU (Intel i9-9900K). Within minutes of startup, the fan ramps up because of the increasing CPU temperature. Prior to this issue, the temperature (reported by Corsair iCUE) would be about 35 degrees C when idle and about 51 degrees C when under heavy load such as gaming. However, since this issue began, while idling after startup the temperate slowly goes from 29 degrees to 69 degree C. During this time, my PC begins to slowly grind to a halt. At this point I usually shut my PC down for fear of damage.

How do I verify that the pump is working? iCUE reports the rpm for the pump, but changing the setting from balance to extreme (shows the increased rpm and it can be heard), does not impact the temperature at all. I also noticed that the radiator remains cool several minutes after the system is on. Is this enough to flag the pump as being defective and causing my overheating issue?

Video of sound: [ame]https://youtu.be/JYV3PYF_SpY[/ame]

Generally, pump speed does not affect coolant temperature in a working cooling system. The typical AIO set-up is 1 block, 1 radiator, and a short run from end to end. Flow rate is not tremendously important.

Your coolant temperature (H115i Temp) is out bounds by quite a bit. I think it was a little high before as well, but certainly now. If the pump was stopped, you would boot up and then shutdown in about 30 seconds. This is more likely to be a partial blockage of some type in fluid pathway and the coolant cannot make the number of trips per interval that is should at either pump speed.

One clear sign you have an issue is if one hose is warm/hot and the other cool. The coolant temp will only drop about 1-2C per pass and that should be an indistinguishable to touch. Clear hot/cold on the either end of the CPU block shows the heat is not getting to the radiator for dissipation. You also can feel this on the exhaust end. If the coolant temp is 50C+, then the exhaust air should be nearly that warm as well. If it is cool, again heat is not getting there and that suggests a blockage.

Contact Corsair Support to start the replacement process or consider your other options.