Mercedes Benz is best known for its top-quality engineering and styling, even among its earlier models. Under its S-Class, the W126 series produced flagship models that were more aerodynamic, more powerful, and more fuel-efficient than their predecessors. The W126 series was unveiled in 1979. Models under this lineup were available in straight-6, V8, and turbo diesel sedan ranges. When it replaced the W116, it sported a new design style, which would be used on future Mercedes Benz models. Aside from having a new design, this line of S-Class Mercedes Benz also featured a number of safety innovations. This series came in several variants: the SE (standard wheelbase), SEL (long wheelbase), SEC (coupe), and diesel models (SD/SDL). The Mercedes Benz 300SLD was introduced under this series. The W126 had a 12-year stint, from 1979 through 1991. It was the longest-running S-Class generation since the mid-50s' flagship models. Due to its high sales volume, the series became the most famous S-Class.
1970s: The W126 was conceived
In 1973, Mercedes Benz had set new plans for the S-Class generation, which would supersede the W116. Under the Project W126, the new S-Class series would have to be enhanced in terms of ride quality, vehicle handling, and fuel efficiency. A newer and better S-Class was designed to be the among the top-selling luxury sedans in the world. In response to the oil crisis of the 1970s, the German automaker focused on improving fuel efficiency, even for V8-powered S-Class vehicles. Lighter materials were used for the W126 design. This range was made to have a sleeker auto body than earlier models. Aside from reduced overall drag, the new series also increased its maximum speed. It took six years to develop the W126 until it was finally launched at the International Motor Show in Frankfurt in 1979. Initially, the W126 series released seven sedan models with standard (SE and SD) and long wheelbase (SEL and SDL): 280 SE/SEL, 380 SE/SEL, 500 SE/SEL, and 300 SD.
W126 models had been revised and redesigned several years after the Energy Program of Mercedes Benz was launched. In 1985, the modified series models were re-launched at the International Motor Show in Frankfurt. These models featured improved aesthetics and upgraded engine variations.
1986: The Mercedes Benz 300SDL replaced the 300SD
The 300SD under the W126 series was eventually replaced by the 300SDL in 1986. The 5-cylinder engine used in previous models was no longer used in the second-generation W126 models. Instead, a new inline six-cylinder engine, which could produce up to 148hp, was used. Models for 1986 and 1987, under California specification, used a diesel particulate filter as diesel cars. Later on, however, the switch was made to a standard diesel oxidization catalyst. The Mercedes Benz 300SDL, which was launched in 1986, lasted only till 1987. It was released in the North American market with about 13,380 units built.