1. Oil has a higher boiling point than water, so it can be used to cool items at a temperature of 100 °C or higher. However, pressurised water-cooling may also exceed 100 °C.

2. Oil is an electrical insulator, thus it can be used inside of or in direct contact with electrical equipment such as in transformers.

3. Oil is already present as a lubricant, so no extra coolant tanks, pumps nor radiators are required (although all of these items may need to be larger than otherwise).

4. Cooling water can be corrosive to the engine and must contain a Corrosion inhibitor|rust-inhibitor, whereas oil naturally helps to prevent corrosion.

5. Thus, if through a gasket failure, coolant oil should enter, say, the combustion chamber or the sump, this would be a mere inconvenience; but if coolant water should similarly leak, substantial engine damage might occur.