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What is Engine Oil Volatility?

By 2021-04-13July 25th, 2021Glossary

Volatility is the property of the lightest fractions of the engine oil to evaporate at high temperatures, which is expressed as a percentage of loss from evaporation after heating the engine oil for one hour at 250 °C.

To determine the vaporizability, or volatility, of motor oil, the Knock method is used. If 850 grams of engine oil are left after heating 1,000 grams of engine oil at 250 °C for one hour, this means that the volatility is 15% (minus 150 grams).

According to ACEA requirements, A1/B1 class oils must not volatilize more than 15%, A3/B3, A3/B4, A5/B5, C1, C2, C3, E4, E6, E7, E9 must not exceed 13%, and C4 oils must not volatilize more than 11% or equal to 11%. If the engine oil is too volatile, it will have to be filled more often and therefore the oil consumption will be high.

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David Muench (Carnes Mechanical)

David Muench (Carnes Mechanical)

Hey, I’m David. I’ve worked in a cars store for 6 years. I write reviews and guides, helping people to choose the most suitable technicals and best product for them. I’m happy to finally share my knowledge of the industry here, on CarnesMechanical.

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