The engineering target was a suitable Diesel engine for the largest available luxury sedan. After consideration of various alternatives including the design of a completely new 6-cylinder engine it was decided to equip the existing naturally aspirated 5-cylinder engine presently installed in the smaller sedan and the coupe with a turbocharger. Development time and cost as well as investment could thus be minimized.This paper describes in detail the complete engine and particularly the modifications required to cope with the higher thermal and mechanical loads, the installation and adaptation of the turbocharger, the adaptation of the fuel injection pump, and the refinements of the combustion process. This work, together with suitable turbocharger characteristics due to wastegate control on the turbine side, resulted in an attractive power plant with very good stationary and transient operational behavior. Finally, engine and vehicle performance data including noise, exhaust emissions and fuel economy are given.