Weird CPU Temp Issue

[Great Success]

Recently my temps were getting a little too high for my tastes(45 idle 80 gaming) so I decided to clean out the case and reapply some thermal paste. Everything went well and my temps dropped dramatically (30c idle, 55 gaming) with fans dead silent. Then couple days later temps are back in the 80's and fans are almost full speed. Did it again and same issue, temps are fine for a couple days then they shoot back up again. What is causing this? Am I supposed to let the paste 'dry' before turning on the computer?

H110i GTX and 4790k.

 

[CountMike]

I would take another look at water block and how tight it is on the CPU. Paste doesn't have to dry before use but may take few days of use to settle down. In any case there has to be just right amount of paste to work at it's best.

 

[Great Success]

Block is secure, this is my third time re-seating it too, same exact symptoms. Day 1 all is well, day 2 noticeably hotter day 3 back in the high 70's while gaming...