|"Anyway ill try to pull out the cpu than place it back to se if this solves the problem."|
There's a 99.9% chance it will NOT !
You DO NOT need to re-seat the cpu if it's working fine and is not overheating ! Even if it is overheating it's probably caused by too much crap on the cpu fan and heat sink or improper overclocking settings - there's probably nothing wrong with the thermal pad's or thermal compound's or thermal grease's effectiveness in transferring heat.
Sometimes thermal compound hardens such that it's like it's crazy glued to the cpu and it's impossible to remove the heat sink from the cpu !
You must replace the thermal compound if it has hardened, or the thermal pad that is between the cpu and the bottom of the heat sink when you remove the heat sink with new thermal compound or thermal grease (replacement thermal pads are hard to find). Thermal grease or thermal compound can be re-used if it's clean, but thermal pad remains must be scraped off.
"while the pc was cool (no program running) ..."
Programs are always running in memory when Windows is running, whether you are running a program yourself or not, but they may not be using CPU time. (Direct Memory Access).
"1 month ago i've cleaned the cooler and the grill of dust ..."
Did you use a vacuum cleaner ?
You're NEVER supposed to use a vacuum cleaner because they produce a tremendous amount of static electricity when they're running and anything connected to them can easily discharge static electricity to components on your mboard and damage them!
"I wonder if its anything i can do to prevent a damage of the cpu?
what do u think ?"
The only thing you can do is wait and see what happens.
The noise may not be significant at all.