The Mercedes-Benz W126 is the company's internal designation for its second generation S-Class, manufactured in sedan/saloon (1979–1991) and coupé (1981–1990) models, succeeding the company's W116 range. Mercedes introduced the 2-door C126 coupé model, marketed as the SEC, in September 1981. This generation was the first S-Class to have separate chassis codes for standard and long wheelbases (W126 and V126) and for coupé (C126).
The long 12-year production (1979–1991) resulted in 818,063 sedans/saloons and 74,060 coupés being built, totaling 892,123. W126 is so far the most successful and the longest in production for S-Class.
History
After the debut of W116 S-Class in 1972, Mercedes-Benz began preparing for the next generation S-Class in October 1973. The project, code-named "Project W126", aimed to provide an improved ride, better handling, and improved fuel efficiency. The oil crisis of 1973 and increasingly stringent emission and safety regulations in the United States had an important influence in developing the W126 for reduced emission and increased fuel efficiency.
The W126 design team, led by Mercedes-Benz's chief designer Bruno Sacco, aimed to design a more aerodynamic shape and retain the unmistakable S-Class design elements. The aerodynamic drag was reduced through lengthy wind tunnel testing and reshaping of front end and bumper along with hiding the wipers underneath the hood/bonnet for smoother flow. Reducing the weight was accomplished by extensive use of high-strength low-alloy (HSLA) sheet and polyurethane deformable material for bumpers and side claddings. The lighter alloy material was used for the heavily revised M116/M117 V8 engines for the reduced weight. Both had contributed to the reduction of fuel consumption by 10% as compared to its predecessor.
After six years of development, the W126 was introduced at the IAA Frankfurt in September 1979. At the introduction, S-Class was available in two wheelbase lengths (standard and long) and three petrol engine options with one six-cylinder inline engine and two V8 engines. The diesel engine option was introduced in September 1981 exclusively for the North American market.
At the 1981 IAA Frankfurt, a coupé version of S-Class, C126, was introduced with 380 SEC and 500 SEC. It was the first time that a coupé version was derived from S-Class chassis. At the same time, the "Energiekonzept" (Energy Concept) was introduced to improve the fuel efficiency of S-Class through engine revisions.
The W126 was revised in 1985 for 1986 model year. The revised "Second Series" model range was introduced at 1985 IAA Frankfurt with new six-cylinder petrol and diesel engines and the V8 petrol engines enlarged to 4.2 and 5.5 litres. The 5-litre V8 was carried over. The visual changes included the smoother bumpers and side claddings, revised "Gullydeckelfelge" (German for manhole-cover wheel rim) alloy wheels, and deeper front bumper with integrated air dam.
The W126 generation was replaced by the W140 in 1991.
Styling
From 1973 to 1975, Mercedes-Benz designers worked on the successor to the W116. After several design concept were presented, the final design for W126 was approved and frozen in 1976. The design work for coupé began immediately after the approval and was finalised in 1977. Design patents were first filed on 3 March 1977 and later on 6 September 1977 at the United States Patent Office.
Compared to its predecessor, the W116, the W126 featured improved aerodynamics with a drag coefficient of Cd 0.36 for the sedan/saloon and 0.34 for the coupés.
Models
The pre-facelift model range (1979–1985 for sedan/saloon and 1982–1985 for coupé) included the 280 S/SE/SEL, 300 SD (North American market only), 380 SE/SEL/SEC, and 500 SE/SEL/SEC. The revised second series (1986–1991) with petrol engines included 260 SE, 300 SE/SEL, 420 SE/SEL/SEC, 500 SE/SEL/SEC, and 560 SE/SEL/SEC. The updated version of diesel model, 300 SDL, was exclusive to the North American market (the first time the S-Class with diesel engine was offered in long wheelbase) and then the 350 SD/SDL (the first diesel S-Class to be available in both wheelbase lengths).