Oil, like air, doesn't convent well in 0G, you'll need pretty hefty pumps and well designed layouts to ensure no hot spots form. Heat pipes are at least passive and don't depend on gravity.
replyMineral oil density is around 900kg / cubic meter.
replyNot sure this is such a great idea.
Does using oil solve the mass problem? Liquids aren't light.
replyI would wager that its lighter than:
replyRepair robots
Enough air between servers to allow robots to access and replace componentry.
Spare componentry.
An eject/return system.
Heatpipes from every server to the radiators.
I would wager it isn't.
replyFirst, oil is much heavier than air.
replySecond: you still need radiators to dissipate heat that is in oil somehow.