Morons... there is a breather filter on the drives to normalize barometric pressure between inside case and outside. Oil will penetrate through this and get on the platters.
A hard drive should never run hot to the point that you need to liquid cool it. The metal case that the drive is mounted in should sink away plenty of heat. Drives may get warm but if running hot then there is a problem.
Additionally there is no overclocking for hard drives, they are only as fast as they are and no faster. Short stroking on a HDD is the closest thing i can think of to trying to squeeze more performance out of one and it will only work for data that is used frequently that is a small partition at the start of the drive where seek time is shortest. RAID 0 would be best for trying to get faster performance from a HDD, but today with super fast SSD's RAID 0 is almost a waste when SSD's are better for speed of data read/write.
I counted at least seven videos. Hard to believe. Whee do people get these ideas?
They have no clue what they are doing is stupid. There is no gain and the drive is going to die when the oil gets past the breather filter. Just because dunking a motherboard in oil will be able to allow for a system to be liquid cooled in mineral oil and overclock well with the heatsink properties of a liquid coolant doesnt mean its a good idea for a hard drive and will give a performance benefit. In fact its a stupid idea to dunk a motherboard and all components as well because you have components that are bathed in oil and the oil would be difficult to remove. In fact a isopropyl alcohol bath is probably the chemically safest way to remove all the oil, but then you have where the slightest spark = a fireball as well as fumes in a confined space = explosion risk. I use to work in PCB manufacturing with a wave solder machine and isopropyl alcohol was used to get flux off of PCB's and then last step was an actual wash in hot water, and then a dryer. I was fortunate that when i started there they stopped using the freon bathing of PCB's before 1995.
If you want to liquid cool buy a kit designed for the specific cooling need and go that route. If you want to damage components lose money and have a mess on your hands listen to youtube and copy someone else that essentially jumps off a bridge with their computer into a oil vat.
Next will be a video of a Optical Drive like an expensive BluRay drive taking a bath because it makes it so much better to be well lubricated and cooled in oil. Maybe even sell someone on the benefit of laser refraction in oil.
