I built this pc in late 2021 with the lian li galahad 240 aio and recently noticed my 5600x idling at 80°-85° and jumping to 95+ with the smallest loads so i assumed it was my cooler and bought an air cooler after this and temps were fine after that.
Out of curiosity, I opened up the aio head to know exactly what had gone wrong as i kept hearing the pump motor start up so i knew the pump hadn't died.
As soon as i opened the head i saw this on the heatsink. All that gunk formed had blocked the copper fins and prevented the coolant from passing through it properly.
Even the coolant had strings of gooey stuff which definitely wasn't supposed to be there
Kinda looks like thermal paste lol