FAQ: ASTM D5800 and the Noack Volatility Test

ASTM D5800 is the standardized method used to measure how much engine oil evaporates under high heat. Commonly known as the Noack Volatility Test, it simulates real engine temperatures to determine how stable an oil is when exposed to extreme conditions.

Low volatility means less oil evaporates during operation. This reduces oil consumption, keeps vyscocity stable, maintains additive balance, and provides more consistent protection over the life of the oil.

Oils with high volatility can evaporate quickly, especially in turbocharged or high-heat engines. This leads to oil loss, thicker vyscocity, increased engine deposits, and reduced fuel economy.

Yes. Turbochargers create extremely high localized heat. If oil evaporates under these conditions, it can leave critical components like turbo bearings exposed to wear and damage.

Essentially, yes. “Burn-off” is the real-world result of high volatility — the lighter parts of the oil evaporate under heat, reducing the amount of oil left to do its job.

ASTM D5800 is the official volatility test method used by specifications like API SP, ILSAC GF-6, GM dexos1 Gen 2, and ACEA. These specs set a maximum volatility % that oils must stay under to be approved.