List of discontinued Volkswagen Group diesel engines. The compression-ignition diesel engines listed below were formerly used by various marques of automobiles and commercial vehicles of the German automotive concern, Volkswagen Group, and also in Volkswagen Marine and Volkswagen Industrial Motor applications, but are now discontinued. All listed engines operate on the four-stroke cycle, and unless stated otherwise, use a wet sump lubrication system, and are water cooled. This transport-related list is incomplete; you can help by expanding it.