Phase A (make s5 start mining in oil) completed.
Here is a simple workaround that made my s5 run in an oil bath.
1) I took an old 3 pins fan, remove the blades and plug it into s5's fan position 1. Kept it in air while running. Virtually no noise, since no blades.
2) Connect stock fan to s5's fan position 2 to move the oil. No noise from here either.
The s5 runs fine till I stop it due to high oil temperature after sometime.
Now I will start with phase B, remove the heat from the oil and make the whole system more stylish
You could probably use a water jacket for cooling. This is another pipe, outside of the oil pip, that allows running water to run around the oil, cooling it down to around room temperature.
This may actually use up less energy than the radiator that you plan to use.
Other than that, sounds quite good what you have already done!