Dexos1™ Gen 3 is a global engine oil specification introduced by General Motors (GM).

The new specification is designed to meet performance needs of GM vehicles and includes a more recent version of the stochastic pre-ignition (SPI) test, fuel economy test, and upgraded performance limits for deposit and sludge tests.

There is some overlap with dexos1 Gen 2 when compared to the latest industry standard, ILSAC GF-6, but dexos1 Gen 3 still has enhanced oxidation, turbocharger protection and engine cleanliness. GM has set a mandatory transition date of January 1, 2022, to meet its dexos1 Gen 3 specification.