What liquid cooler.
How precisely did you follow directions (that includes remembering to pull the safety plastic off the pump base)
Did you use the correct standoffs for your cpu? Or use the other ones because they looked nicer? (Intel is usually silver, amd is usually like a black chrome, different heights)
Is it tight? Or is it as more than a few posts have seen, not tight enough because of fear of damaging the cpu?
Have you downloaded the latest/last bios and motherboard chipset drivers? (same place, not the ones for your graphics card)