The Mercedes-Benz W108 Series premiered at the Frankfurt Auto Show in 1965. The initialmodel range consisted of three W108s (250 S, 250 SE, and 300 SEb). Theinline-six engines were carried over from the previous generation withmechanical refinements. The 2.2-litre M180 engine was enlarged to 2.5litres while the fuel-injected 3-litre M189 version was carried over from"300 Adenauer".