Fix NUC8i7BEH overheating

Place the NUC upside down and select a PH2 Phillips screw driver bit

Start by using a Phillips head #2 screw driver to remove the lower screws on the lower case door.

These screws are held in with retainers, so they won't fall out when you flip the lid.

Lift the door, and keep an eye on the cables that connect to the NUC's motherboard. These cables are the power and data cables for the 2.5" hard drive bay.

Carefully unplug the cables from the motherboard, and set the bracket aside.

In the last photo, the slot for a blade SSD is marked with a red arrow. This is where you would install the blade SSD, and use a screw to hold it in place.

Change the screw driver bit to the PH1 one.

Unscrew the V-NAND SSD and carefully slide it out of its connector.

Previous step as video

Change the screw driver bit to PH1

Unscrew the screws marked in red circles

Remove the WiFi and Bluetooth antenna cables (be extremely careful when doing this otherwise you risk to rip the base contact terminal off the PCB)

Remove the stereo mic cable from the motherboard connector.

Pay attetion to the WiFi cable hidden under a black piece of tape

Disconnect mic cable

Remove padders from the sides

Not all are necessary only the two depicted.

Use a pry tool to lift the motherboard from the casing

Marked with red circles the dust signs evident on first sight

Remove the 3 screws fixing the CPU fan

Remove the fan power connect from the motherboard

You will need to use compressed air, a small vacuum cleaner or something similar to blast off all the stucked dust.

I'm using a compressed air can (optional)

Video of the procedure

Video of the procedure

This step is probably not necessary, but for the sake of completeness here it is.

Remove the screws holding the CPU cooler following the numbers on them.

Use isopropyl alcohol for this, be careful not to touch the the thermal pads on the chips around the CPU.

Be careful not to apply too much of it.