NOACK Volatility

ASTM D5800 - 08 Standard Test Method for Evaporation Loss of Lubricating Oils by the NOACK Method

NOACK volatility determines the evaporative loss of engine oils. This test is important because the operating temperatures of an engine will typically drive off the lighter ends of a lubricant while in service. This effectively results in pushing the viscosity of the lubricant to a more viscous level (up) and, as a result,  fuel economy goes down due to an increase in parasitic load. 

The evaporation loss is of particular importance in engine lubrication. Where high temperatures occur, portions of an oil can evaporate. Evaporation may contribute to oil consumption in an engine and can lead to a change in the properties of an oil.