My Nitro 5 (i5 8300H(2.3GHz)/8 GB/256 GB(M2 SSD)/GTX 1060 6GB) emits a low volume grinding noise almost constantly while the computer is on, only stopping for less than half a second every now and then. It originates from the left side of the keyboard, under the 'Caps Lock'-key.
The sound stops if the power cable is removed, and starts almost instantly when it's plugged in again.
It's not audible while the computer is turned off, even if plugged in.
During the startup process, it becomes audible almost instantly.
It's been happening for at least a month.
I've made no hardware upgrades, not overclocked.