I have a Kraken x61 I'm really not digging the stock 140mm fans it comes with, I'm getting great temps and everything is fine except the one fan rattles from where it spins and is becoming annoying as the rest of my system is dead silent. So I've done some research and have decided to replace the stock 140mm fans with Noctua NF-A14 PWM 140mm fans, i was gonna grab the 2000rpm industrial Noctua 140mm fans that are black and brown but they are very loud. My question is can i just unscrew my radiator from my case while leaving the pump and block still connected to my Motherboard and cpu and replace the fans then put the radiator back in the case or do i have to completely take off my Kraken x61 and replace them? I'm trying to avoid have to reapply thermal paste and wasting whats on there and for it to be as simple as possible, so basically can i replace my fans while the pump/block is still connected to the mobo and cpu?