Unless where you live the current ambient temperature is around 40 degrees, you have probably not installed it correctly
When idling, the CPU should be no more than 10 degrees above ambient.
Have you used thermal paste? Which one and how much?
When fastening the waterblock on the CPU, did you go on until all screews ran out of thread? Did you do it progressively, in a X fashion? (i mean: you start fastening a screw a little, then you pass to the one in the opposite side, then the other pair, etc.: tightening a little each screw so that never does one side have much more pressure than any other?)
Then you have to plug the pump into the CPU fan header.