h55 performance decrease

i bought a corsair h55 before Christmas but didnt install it until the beginning of january, anyway i was amazed with it at first 19-23 degrees on idle and only 44-48 on load, however now theres a problem. I went away for a week from last monday until monday just gone and my cpu temps are now spiking and idle temps are fluctuating between 28-40 and my load temps are hitting 66, that's shambles, my stock cooler hit 66.......... the radiator is starting to get really hot and so are the pipes.



ambient temp has stayed the same around 24 and like i say my pc wasnt touched for a week so how can it start spiking all of a sudden.