So is it only the motherboard/CPU/RAM/videocard that are submerged in the oil? Are the fans on the CPU/GPU running or removed, because they appear to be moving, but that could just be an effect of the air bubbles? I checked the youtube page but he didn't provide those details.

I see the HDD/CD and of course PSU are not submerged, as well as the power connector on the motherboard. I wonder why he has those two external fans hooked up?