What Is Semi-Synthetic Motor Oil?

by Jennifer Leighton
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Semi-synthetic is a type of motor oil that is a blend of other types of oil. Semi-synthetic motor oil was formulated to provide some of the benefits that pure synthetic oil offers.


Semi-synthetic motor oil is a mineral oil blend containing 30 percent or less synthetic oil.

Synthetic Oil

Synthetic motor oil is created entirely from chemical compounds that do not include crude oil. Synthetic motor oil often has superior performance when compared to crude oil.

Crude Oil

Crude oil, or petroleum, is the base of both semi-synthetic and other mineral oils. Crude oil is combined with synthetic oil to make a semi-synthetic oil.


Semi-synthetic motor oil is lower in price than pure synthetic oil, but is more expensive than crude oil.


Semi-synthetic oil offers some of the same advantages as pure synthetic oil. These include improved oil viscosity at hot and cool temperatures, less loss of product due to evaporation, and extending the life of the car motor.


The first semi-synthetic motor oil was launched in 1966 by the MOTUL corporation. This was followed the the introduction of fully synthetic motor oil in 1971.

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