OM 138 Engine, 1936
The engines which Mercedes became famous for were diesel engines. The first unit of this type, Mercedes-Benz OM 138, was developed and built for passenger cars. It took three years to make and was the first diesel engine used in a mass-produced passenger car – Mercedes 260 D (W 138). The model earned a reputation for being economical and reliable, and the cars with this engine were very popular with taxi drives.