Your pump oil’s durability depends on many parameters and temperature has a big influence. Too hot or too cold, both can cause issues. An overview: Mineral oils: their max temperature limit would be 80°C (176°F), above that the oil will thicken. We find that every 10°C temperature increase reduced the oil service life by half. Synthetic oils endure a permanent operation at 100-160°C (212-320°F). PFPE oils are almost inert, they’re not as subject to typical oil ageing. Therefore, PFPE oils can stand permanent temperatures of up to 250°C (482°F). Operating conditions can also be too cold for the oil and as a result, water (and other) vapors may condense. Condensed liquid can cause loss of lubrication properties and even corrosion in the pump.