Chosen Solution

I disassembled my PS3 to change the thermal paste. I used relatively thin layer of good quality paste (Thermal Grizzly), while spreading it evenly on CPU and GPU. At first it worked relatively quiet (but not much different from what it was before changing the paste), but after a while it seems that fans kick into 100% RPM, even while sitting into XMB. The air coming out of the console seems to be relatively cold and the console doesn’t shut down from overheating. I double checked and the pressure plate seems to be firmly attached. What should I do next?

That sounds like something like a thermometer being punctured. Also put bean size. I bet if you remove the metal plate paste has leaked

have you found the problem my friend ? mine did that too and the rsx goes to 80°c within a minute of powering it on i have replaced psu and new fan and applied new thermal paste but still no luck