The Mercedes-Benz W126 was a series of flagship vehicles manufactured by German automotive marque Mercedes-Benz. Premiering in September 1979 as the successor to the earlier W116 line, the W126 was the second generation of the Mercedes-Benz flagship to officially bear the S-Class name referring to Sonderklasse or "special class." The W126 was initially offered in straight-6, V8, and turbo diesel sedan models. In September 1981, 2-door coupé versions of the W126 were introduced. Compared to its predecessor, the W126 was more aerodynamic, fuel efficient, capacious, and powerfully engined. The W126 S-Class debuted a new Mercedes-Benz design style which was subsequently used on other vehicles in the company's lineup. The W126 line also introduced many notable Mercedes-Benz safety innovations, including the first airbag supplemental restraint systems, seatbelt pretensioners, and traction control.
The W126 had a twelve year production run between 1979 and 1991, the longest of any S-Class generation since the flagship models were first built in the mid-1950s. The different body styles of the W126 S-Class achieved a combined sales total of 892,123 units (818,063 sedans and 74,060 coupés), making the W126 the most popular S-Class ever produced.
In terms of the body design, the objective of the W126 design team, led by Mercedes-Benz's Bruno Sacco, was to produce a car that was sleeker and more aerodynamic (and thus lighter and faster) than the previous model. The application of lighter materials and alloys combined with thorough wind tunnel testing to reduce overall drag meant the car consumed about 10% less fuel than its predecessor. The maximum speed was also increased (250 km/h in the most powerful model).
After six years of development, the W126 was formally introduced at the Internationale Automobil-Ausstellung (International Motor Show, or IAA) in Frankfurt on September 1979. The initial lineup featured seven models in standard (SE, SD) and long (SEL, SDL) wheelbase sedan body styles: the 280 SE/SEL, 380 SE/SEL, 500 SE/SEL and 300 SD. Technically, the long wheelbase (SEL) variants were codenamed V126, but this was not popularly known. In 1981, the coupe version (SEC) of the W126 S-Class premiered at the IAA with the 500 SEC model. In 1981, Wheels Magazine selected the W126 model 380 SE as its Car of the Year.
Four years after the introduction of the fuel-efficiency "Energy Program," the model range had been reworked completely. In September 1985, again at the IAA in Frankfurt, the reworked model range was reintroduced. Apart from visual changes to the bumpers, side covers and alloys, the changes made to the available collection of engine variants was most visible. Two newly-constructed 6 cylinder engines and a new 4.2L V8 were added, and other engines were further upgraded.
The interior featured pleated leather on the doors, woodgrain trim on the center console and across the dash, and a simplified layout with symmetrically placed buttons.
The W126 S-Class carried the following general dimensions: length (sedan), (coupe); width (sedan), (coupe); height (sedan), (coupe), wheelbase (sedan), (coupe).
|W126.021||1981-1985||280 S||M110.924 2.8L straight-6 carburetor||World excluding US|
|W126.022||1981-1985||280 SE||M110.987 2.8L straight-6||World excluding US|
|W126.023||1981-1985||280 SEL||M110.987 2.8L straight-6||World excluding US|
|W126.12||1981-1985||300 SD||OM617.951 3.0L straight-5 diesel||USA and Canada only|
|W126.032||1984-1985||380 SE||M116.963 3.8L V8|
|W126.033||1981-1983||380 SEL||M116.963 3.8L V8|
|W126.043||1982-1983||380 SEC||M116.963 3.8L V8|
|W126.036||1984-1985||500 SE||M117.963 5.0L V8||World excluding US & Aus|
|W126.037||1984-1985||500 SEL||M117.963 5.0L V8||for US and Canada '84 and '85|
|W126.044||1984-1985||500 SEC||M117.963 5.0L V8||for US and Canada '84 and '85|
|W126.12||1986-1991||260 SE||M103.941 2.6L straight-6||World excluding US & Australia|
|W126.024||1988-1991||300 SE||M103.981 3.0L straight-6||'89-'91 US|
|W126.025||1988-1991||300 SEL||M103.981 3.0L straight-6||'88-'91 US|
|W126.125||1986-1987||300 SDL||OM603.961 3.0L straight-6 diesel|
|W126.134||1991||350 SD||OM603.97 3.5L straight-6 diesel|
|W126.135||1990-1991||350 SDL||OM603.97 3.5L straight-6 diesel|
|W126.034||1986-1991||420 SE||M116.965 4.2L V8||World excluding US|
|W126.035||1986-1991||420 SEL||M116.965 4.2L V8|
|W126.046||1986-1991||420 SEC||M116.965 4.2L V8||World excluding US|
|W126.036||1986-1991||500 SE||M117.965 5.0L V8||World excluding US|
|W126.037||1986-1991||500 SEL||M117.965 5.0L V8||World excluding US|
|W126.044||1986-1991||500 SEC||M117.965 5.0L V8||World excluding US|
|W126.038||1986-1991||560 SE||M117.968 5.6L V8||n/a in US, Australia|
|W126.039||1986-1991||560 SEL||M117.968 5.6L V8|
|W126.045||1986-1991||560 SEC||M117.968 5.6L V8|
The 500 SEL has an interesting place in US history, since American demand for this particular car drove the establishment of a large grey market. The detuned, yet very expensive US specification 380 SE/SEL/SEC was underpowered, according to contemporary reports, and fuelled demand for the more powerful version available in the rest of the world. Approximately 22,000 units per year of grey market Mercedes-Benz (including the 500 SE/SEL) were sold in the early 1980s, according to contemporary reports in the Los Angeles Times.
Some engines had a design defect which causes ovaling of cylinders' walls, bent rods, excessive oil consumption (1 quart per 200 miles or one litre per 300 kilometres is not uncommon), and eventually engine failure. Mercedes-Benz did not accept responsibility for this defect, even when problems arose before warranty terms were met. Most of these engine failures have so-far occurred on vehicles driven under high load or city driving, while highway driven engines do not show signs of problems until many miles later, if at all. Fixing the problem can cost the owner more than $10,000 or 8000€ which exceeds the value of the car. All 350 SD/SDL's will develop this issue, but will not reoccur after being repaired, therefore a thorough pre-purchase check by a qualified mechanic can give the potential buyer a better idea of what they are getting into. Some 350s have gone well over , problem free.
The reason for the susceptibility of a single row chain on this engine is because of the intricate rails and tensioner design, along with the two tall cam towers the chain must circulate around. Simple single cam engines generally do not have these problems when using a single belt.
The most spectacular new engine was the 5.6 litre V8 that was a further development from the 5 litre version. An increased stroke meant it could turn out a hefty . There was a higher compression version available, if required, that produced some . This version was only available without catalytic converter. But even without the catalytic converter this ECE version, as it was known, would meet the emission requirements of the European community.
A 3.0 litre inline 5 cylinder turbo diesel was offered from 1981-1985 in North America. They are known for covering many hundreds of thousands of miles with few problems. In 1986 the 300SD was replaced with the 300SDL. It was simply a stretched version of the 300SD but the 5 cylinder engine was replaced with a new inline 6 cylinder which improved power and put some of the sluggishness of the previous diesel away.
|2.6 12V||I6||From MY 1986|
|2.6 12V*||I6||From MY 1986|
|2.8 12V carb.||I6||11.0s||MY 1980-1985|
|2.8 12V inj.||I6||10.0s||MY 1980-1985|
|3.0 12V*||I6||From MY 1986|
|3.0 12V||I6||From MY 1986|
|3.8 16V||V8||MY 1980-1981|
|3.8 16V||V8||9.3s||MY 1982-1985|
|4.2 16V*||V8||MY 1986|
|4.2 16V||V8||9.0s||MY 1986|
|4.2 16V*||V8||8.3s||From MY 1987|
|4.2 16V||V8||8.1s||From MY 1987|
|5.0 16V||V8||8.0s||From MY 1986|
|5.0 16V||V8||MY 1980-1981|
|5.0 16V||V8||8.1s||MY 1982-1985|
|5.0 16V||V8||7.6s||MY 1986|
|5.0 16V*||V8||MY 1986|
|5.0 16V*||V8||7.5s||From MY 1987|
|5.0 16V||V8||7.3s||From MY 1987|
|5.6 16V*||V8||7.6s||MY 1986|
|5.6 16V*||V8||7.2s||From MY 1987|
|5.6 16V||V8||MY 1986|
|5.6 16V RÜF||V8||From MY 1987|
|5.6 16V ECE||V8||6.9s||MY 1986/87|
|3.0 TD||I5||16.0s||MY 1980-1985|
|3.0 TD||I6||13.0s||MY 1986/87|
|3.45 TD||I6||13.0s||MY 1990/91|
Note: * = Catalyst version
The W126 S-Class, the most successful production S-Class in history, has secured a place as one of the most well-remembered luxury vehicles--described by some as a "classic." Its twelve-year production run was longer than any S-Class before or since, and following the debut of the W140 S-Class in 1991, the additional two years of production in South Africa was a testament to the W126's popularity in the export market. Although an expensive car to maintain, mostly due to the increased expense of Mercedes-Benz replacement parts, a late model W126, if properly driven, can still be a viable proposition today. Many W126s have been prominently featured in films long after production ended.
This legacy stands in contrast with the W140 chassis which had very complex accessory systems, particularly the W140 HVAC system, electrical wiring (due to the push to manufacture environmentally friendly plastics), and auto-door closing features. Among actual owners, W126s are known for their simple maintenance, straight forward problems diagnosis, and long term reliability. It is one of the last Mercedes-Benz models that was still easily maintainable and repairable by owners.