Mercedes-Benz's history of straight-six engines began with the 1913 Mercedes D.I aircraft engine. The first automotive straight-six engine was the 1924-2929 "Daimler M836" 3.9 litre engine. Following World War 2, Mercedes resumed production of straight-six engines with the Mercedes-Benz M180 SOHC engine, which was produced from 1951 to 1985. Following that introduction, the company produced two lines of petrol straight-six engines; one smaller version and one larger version. In 1985, the Mercedes-Benz OM603 diesel straight-six engine was introduced. a diesel in 1985. In 1996, the company replaced its petrol straight-sixes with a series of 90° M112 V6s, although it continued to produce diesel straight-six engines. Production of petrol straight-six engines resumed in 2017 with the introduction of the Mercedes-Benz M256 turbocharged DOHC engine.