Noack Test: Measuring Evaporation Loss in Motor Oils

Learn about the Noack test for volatility and evaporation

The Noack Test is an important test used to evaluate the volatility and evaporation loss of engine oils and lubricants. It was developed in the 1950s by E.R. Noack and provides a measure of an oil’s resistance to evaporation at high temperatures.

The test involves heating a sample of the oil to 250°C under nitrogen atmosphere for 60 minutes. The weight loss of the sample during this process is measured and reported as a percent. Oils with lower Noack volatility (weight loss) are considered more stable at high temperatures. Typically, high quality engine oils will have a Noack volatility below 15%.

The Noack test helps assess two key aspects of engine oil quality and performance:

Volatility – Oils with lower Noack volatility will be less prone to evaporative losses at high operating temperatures in the engine. This helps maintain viscosity and oil pressure while reducing oil consumption. Highly volatile oils can form deposits and lacquer on engine parts.

Oxidation resistance – The Noack test puts thermal stress on the oil which accelerates oxidative thickening. Oils that undergo less evaporation tend to have better oxidation resistance and stability. This allows the oil to retain its viscosity, detergency and lubricity properties for longer periods under high temperature operation.

During the Noack test, the more volatile components in the oil such as light hydrocarbons and additives evaporate. This leads to an increase in the oil’s viscosity, acidity and tendency to form deposits. So the more an oil loses through evaporation, the faster it will deteriorate in these aspects.

The Noack volatility depends on the oil’s base stock composition and additive package. Synthetic and highly refined mineral oils have lower volatility compared to lower quality mineral oils. Effective antioxidant additives also help minimize evaporation losses.

Who uses the Noack test?

By engine oil manufacturers and blenders

Lower Noack volatility is required for modern higher performance motor oils such as those meeting API SN or ILSAC GF-6.

By race car teams and enthusiasts

To choose low volatility oils that reduce oil consumption and maintain protection at very high engine temperatures and RPMs.

The Noack test is an ASTM D5800 test to determine the amount of evaporation loss of certain lubricants in a motor oil

©, 2021 Rick Muscoplat