And once you remove all the moving parts, you just fill the whole thing with oil rather than air and let heat transfer more smoothly to the radiators.
Not sure this is such a great idea.
Repair 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.
Second: you still need radiators to dissipate heat that is in oil somehow.