The data obtained by distillation method is only rough result, and the evaporation loss of lubricating oil products needs to be determined by special method. China's method for determining the evaporation loss of lubricating oil is GB/T lubricating oil and grease evaporation loss determination method and SH/T lubricating oil evaporation loss determination method (Noack method.) The GB/T method is to put the lubricating oil specimen in the evaporator and place it in a constant temperature bath at a specified temperature, with hot air passing over the surface of the specimen for 22 h. Then the evaporation loss is calculated according to the mass loss of the specimen. According to this method, the evaporation

loss of lubricating oil products can be measured at any temperature within 99-150℃.

At present, this method is mainly used in China to evaluate the evaporation loss of grease and synthetic lubricating oil, and the SH/T method is to heat the specimen in the specified apparatus under the specified temperature and pressure for 1h, and the evaporated oil vapor is carried out by air flow. The evaporation loss of lubricating oil is determined according to the difference of the specimen volume before and after heating.