At Friedrichsruhe Castle near Öhringen, Audi presented the Audi 100 5D to the public in autumn 1978. The vehicle was powered by a five-cylinder diesel engine developed by Volkswagen. To demonstrate the engine’s reliability and performance, two meticulously prepared yellow sedans departed from Audi’s Technical Development Center in Ingolstadt early in the morning of August 21, 1978, embarking on a 66-day journey around the world. After covering 30,800 kilometers and spending 40 days on the road, both vehicles and their crews arrived safely at Friedrichsruhe Castle on October 25, shortly before midnight, where they were welcomed by a distinguished gathering of journalists and guests.
The five-cylinder diesel engine was available in all trim levels, but exclusively in combination with a four-speed manual transmission. A total of 55,613 customers chose the somewhat underpowered yet economical diesel sedan. The diesel revolution of the late 1980s was still many years away.