I had a Intel Skull Canyon NUC for long. It has a tendency to overheat itself. Sometimes it overheats itself too much that it restarts/thermal shut down. I had a plan for long to remove that small heatpipe heatsink and small blower fan and add a bulky heatsink and large fan to cool it down properly. As it has a core i7 6th generation processor, It definitely takes a lot of power and that comes out as heat.
I had this fan lying around that is removed from a peltier cooler unit. But this has a bit larger surface than the available space around the processor die was a bit smaller than the heat sink surface. So I have to use a hand grinder to grind a little bit on the 2 sides of the heat sink.
After preparing the heatsink, I have cut up the top cover above the CPU. There is no actual measurement. But there is hints by intel. They placed 3 rubber to press down the existing heatpipe heatsink over cpu die. Draw a square along the outside of the 3 rubber and then remove those rubbers. Then use a hand grinder and a cutting disc or a dremel if you prefer, to make a square hole on the top metal cover. Then try to insert the heatsink base inside by tilting it. The hole must be a bit smaller than the heat sink base. If the heat sink base cannot be inserted then you have to make the hole a bit larger and try again. When it can be inserted like the following images, I need to clean the burrs using a file and then a sandpaper.
Then the motherboard is cleaned up and the processor die is carefully cleaned with alcohol wipes from any previous residue of thermal paste. Then the motherboard is taped well as I thought the heatsink is not screwed with the motherboard and it is a press-fit. It can move and short the inductors near the CPU die.
Then I have applied proper amount of thermal paste over the CPU die and on the die near it. Then taken help from my younger brother. While he was installing motherboard, I was aligning the heatsink over cpu die. It was a bit hard to place the motherboard to its original place and scerew it because the heatsink I have used has a base that is 1mm thicker than the available space over the cpu die and the top metal cover. Then we scerewed the motherboard properly. The heatsink fit so hard that even without any glue, we can pick up the nuc by holding the heat sink.
The motherboard and top metal cover both are bent a little bit.
I have tried it to run without fan. It heats up slowly but it becomes hotter that I cant touch within 5 minutes when running windows 11. So I installed a 12v fan over the heatsink. The wiring is pretty straightforward, the red wire from the processor fan is 12v+ and black wire is GND. I want to keep the previous fan inside the nuc also to make airflow inside the nuc when the case is closed and cool down the ram, SSD and other chips. This is normal test image and a stress test with CpuZ:
By the way, This is with the default settings of bios as the bios is reset as I have removed the CMOS battery when working.