The Mercedes-Benz 260 D, coded Mercedes-Benz W 138 according to internal works designation, was the first passenger car with diesel engine in a series production. The 260 D was named in reference to its engine displacement. Nearly 2,000 vehicles were assembled until 1940 when the Daimler-Benz devoted itself almost entirely to military manufacture.
Pilot series
An early attempt by Daimler-Benz to install a 6-cylinder diesel engine in a Mercedes-Benz Mannheim chassis ultimately failed due to its unacceptable vibration. 1935 saw the successful installation of the smaller OM 138, 2545 cc overhead valve, 4-cylinder engine in a Mercedes-Benz 230 (W21) chassis. It employed the Bosch diesel fuel injection system and produced 45 bhp at 3000 rpm. The car weighed approximately 1530 kg and could attain a top speed of 95 km/h. Branded as the 260 D, the car was introduced to the public at the 1936 Berlin Motor Show, although 13 pre-production units were produced the previous year.[1] The car proved to be a good seller.[2]