Nikolaus August Otto founded the company in Cologne in 1864, and it was there that he developed the four-stroke internal combustion engine in 1876, with Gottlieb Daimler and Wilhelm Maybach among his early collaborators. Generally regarded as the world's oldest engine manufacturer, the firm later operated as Klöckner-Humboldt-Deutz before returning to the Deutz name.

Deutz air-cooled diesel engines, especially the FL912, FL913, and FL413 families, earned a worldwide following because they need no coolant and shrug off dust, heat, and neglect. They powered tractors, harvesters, compressors, pumps, boats, and generating sets on every continent, and the modern water-cooled TCD engines continue the tradition in agriculture and industry. Browsing the FL range is a tour of industrial history.

Deutz manuals cover fuel injection pump timing and calibration, valve clearance adjustment, cylinder head and piston overhaul, blower and cooling system service, lubrication circuits, electrical systems, and fault diagnosis, with detailed torque tables and wear limits for each engine series. Scheduled service intervals and cold-start procedures are set out for each family. Air filter service is documented for dusty-site engines.

Farmers running Deutz-powered machinery, plant and equipment operators, marine genset owners, and workshops in remote locations all rely on this literature. Air-cooled engines in particular reward disciplined, well-documented maintenance, and the parts catalogues bound with many manuals speed up sourcing for engines built half a century ago.