1.Oil has a higher boiling point than water and can therefore be used to cool articles at temperatures of 100 ° C or higher. However, pressurized water cooling may also exceed 100 °C.
2.Oil is an electrical insulator, so it can be used inside or in direct contact with electrical equipment such as 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 may be corrosive to the engine and must contain rust inhibitors, which naturally help 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; however, if the cooling water should leak as well, serious engine damage may occur.
1. The cooling oil may be limited to cooling objects of about 200-300 ° C, otherwise the oil may degrade or even leave a gray deposit.
2. Pure water may evaporate or boil, but it will not degrade, although it may be contaminated and acidic. And acidic.
3.Water is generally available should coolant need to be added to the system, but oil may not be.
4.Unlike water, oil may be flammable.
5. The specific heat of water or water/glycol is about twice that of oil, so a given volume of water can absorb more engine heat than the same volume of oil.
6.Therefore, water may be a better coolant if an engine is permanently producing large amounts of heat, making it better for high-performance or racing engines.