Is there a heatpipe? Those can fail. They can leak and the fluid is lost. Then the heatsink becomes quite ineffective.

No only simply alublock with blower.

i already replaced cooling paste and for sure it is sitting tight. Also replaced the fan. no sucess..
it seems its a design mistake.. a ghz you can`t use... except for less den 20 C° room temperature.

if i install a proper socket a cooler with the mainboard on my desk it works..
but it will not fit inside the notebook :>

Might be that the voltage regulation on the motherboard is broken and your cpu runs overvolted.
Happened in the past more often on laptop motherboards causing them to cook the cpu.

Most annoying if you had a soldered cpu, then you needed to replace the whole board.