Mercedes-Benz S-Class, W 116 series (1972 to 1980)

A brand-new premium-class vehicle generation was presented to the public in September 1972. The first officially designated “Mercedes-Benz S-Class” – internal designation W 116 – replaced the W 108/109 series and was initially comprised of three models: the 280 S, 280 SE and 350 SE. The 280 S and 280 SE models featured the six-cylinder engine M 110 with dual overhead camshafts that had made its debut in the W 114. Six months later the S-Class saloon was also offered with the larger 4.5-liter V8 engine in parallel to the 450 SL and 450 SLC. At the same time the 450 SEL was introduced, its wheelbase lengthened by an extra 100 millimetres; as with its predecessor models, the additional space served to increase legroom in the rear. The long version was also available from November 1973 as a 350 SEL and from April 1974 as a 280 SEL.
One noteworthy engineering innovation first featured as standard in the W 116 series saloons was the double-wishbone front suspension with zero-offset steering and anti-dive control, as tested originally in the C 111 experimental vehicle. This permitted further dynamic handling improvements. Rear suspension was essentially the same as the design that had by this stage been tried and tested over many years in the Stroke Eight models and which was also in use in the 350 SL. The 4.5-litre models were fitted with a coupled-link axle.
High level of security
In terms of passive safety, too, the S-Class was at the forefront of engineering. The variety of safety design features integrated for the first time into the 350 SL were of course included without exception in the S-Class saloons. The fuel tank, for example, was no longer positioned in the rear end but above the rear axle for protection in case of accident; in the interior, maximum protection was offered by the heavily padded instrument panel, yielding or recessed switches and levers, and a four-spoke safety steering wheel with impact absorber and broad padded boss. The most significant improvement over the predecessor series was the even stronger safety passenger cell with stiffened roof-frame design, high-strength rigid roof and door pillars and reinforced doors. By controlling the deformability of front and rear end it was also possible to improve considerably energy absorption in the front and rear crumple zones.
Special wind deflectors on the A-pillars guaranteed good visibility. In wet conditions these served as channels for dirty water, keeping the side windows clean in bad weather. Other safety features included wrap-around turn indicator lamps that provided good visibility even from the sides, and large rear lights, which offered good resistance against soiling thanks to their ribbed surface profile.
The Mercedes-Benz 450 SEL 6.9
In May 1975 the company presented the 450 SEL 6.9 – the new top model in the series and true successor to the Mercedes-Benz 300 SEL 6.3. The powerful 6.9-liter V8 engine, developed from the highly successful 6.3-liter unit, achieved an output of 286 hp (210 kW) and maximum torque of 56 mkg (549 Newton metres). The hydropneumatic suspension with self-levelling – featured for the first time in a Mercedes-Benz passenger car – guaranteed the utmost in ride comfort. Other special equipment included in the standard specification for the top-of-the-range model were the central locking system, air-conditioning and a headlamp wash/wipe system. As was the case with its direct predecessor, the 450 SEL 6.9 proved an immediate success; although it was more than twice as expensive as the 350 SE, a total of 7,380 units were built during its four-and-a-half year production period.
Between November 1975 and February 1976 the direct fuel injection system in the 2.8-liter, 3.5-liter and 4.5-liter injection engines was converted to fall in line with more stringent emissions standards now in force in most European countries. The electronically controlled Bosch “D-Jetronic” was abandoned in favour of the newly developed mechanically controlled Bosch “K-Jetronic”. In all three cases conversion was achieved with only minor loss in output; at the same time, compression was slightly reduced in the 2.8-liter and 3.5-liter engines. For ease of maintenance these modifications also included breaker-less transistorized ignition and hydraulic valve clearance compensation for both V8 engines.
As with the 2.8-liter injection engine, compression was reduced also in the carburettor engine, similarly causing a slight decrease in output. Two years later, from April 1978, the original output was once again offered in all three models with injection engines. In contrast to the carburettor version, compression in the 2.8-liter injection unit was raised to its old value, and the previous output in the two V8 models was achieved largely by modifications to the exhaust system.
A diesel in the S-Class
In May 1978 the model range in the W 116 series was expanded even further. As the latest addition to the family, the 300 SD attracted just as much attention among connoisseurs as had done the 450 SEL 6.9 three years earlier – although it was positioned at the opposite end of the performance scale. For the first time in the history of this vehicle category, the new S-Class model was powered by a diesel engine. The 3.0-liter five-cylinder unit, that had proved so successful in the mid-range 240 D 3.0 and 300 D models, was given a turbocharger for its new role, enabling output to be increased to 85 kW (115 hp). Development of this unusual S-Class variant, which was offered exclusively in the USA and Canada, was begun with the aim of meeting the fuel consumption standards recently introduced by the US government. The most decisive factor here was the so-called Corporate Average Fuel Economy, an invention of the Carter administration, which denoted the average fuel consumption of all passenger car models in a manufacturer’s range. By extending the range to include conventionally economical diesel models it was possible to bring the fleet’s average fuel consumption under the legal limit.
A technical innovation of ground-breaking significance was offered as a world exclusive in the S-Class saloons of the W 116 series from fall 1978: The anti-lock brake system (ABS), developed in collaboration with Bosch, which guaranteed a vehicle’s unrestricted steering response even under emergency braking and thus made a vital contribution to active safety. Today almost a commonplace and available even in small cars, at the time the market launch of ABS was seen as nothing short of sensational.
Safety of a rather different nature was offered by the armoured version of the W 116 series. Protection design underwent further improvements based on the sum of experience gained during development of the armoured 280 SEL 3.5. Taking the eight-cylinder models as a whole – the 350 SE, 350 SEL, 450 SE and 450 SEL – a total of 292 units were built as armoured vehicles for delivery to special customers, including many state institutions in Europe and overseas.
The successors to the first S-Class series – the W 126 models – were presented in September 1979 at the Frankfurt IAA. But that did not put an immediate end to the W 116 series; production was gradually phased out for each model between April and September 1980. Of the 473,035 units built in this model series, the last vehicle to leave the Sindelfingen plant was a 300 SD.
The W 116 series in the press
Auto, Motor und Sport, Germany, volume 2/1973, on the Mercedes-Benz 350 SE:
“The pleasure of driving a Mercedes 350 SE is sadly an expensive one and affordable only by a minority. This is regrettable, because for the considerable financial outlay one gets not only representation and a status symbol, but also more importantly a wealth of benefits that one would wish for in any car: A high degree of active safety and crashworthiness, perfected body design, outstanding comfort, large reserves of energy, effortless driving and exemplary craftsmanship. And all these highly desirable features come together to form an overall image in which one thing stands out above all – that this is one of the world’s most perfect cars.”
Car, England, June 1975, on the Mercedes-Benz 450 SEL 6.9: “A car of such speed and weight must have demonstrably good roadholding and handling, and this one is no disappointment in anything from a hairpin to a three-figure-bend: the suspension soaks up the bumps, the transmission is wonderfully smooth and admirably easy to control (either by a sensitive accelerator foot or a hasty hand at the lever), and the steering is servo-assisted in a way that highlights the nearly neutral responses of the vehicle.”
Automobil Revue, Switzerland, May 15, 1975, on the Mercedes-Benz 450 SEL 6.9: “It is a real joy, given the present climate, to witness the launch of a car that offers the connoisseur the utmost in driving pleasure – and at any speed. The 6.9 is testimony not only to the optimistic outlook of those responsible for its design, but also to their having the courage of their convictions.”
Mercedes-Benz 450 SEL (116 model series S-Class, 1973 to 1980).
116 model series Mercedes-Benz S-Class Saloon (1972 to 1980), advertisement. Key message: a luxury-class saloon needs more than just a powerful engine. Safety, performance and comfort are the right mix.
116 model series Mercedes-Benz S-Class Saloon (1972 to 1980). The distinguishing features of this model series included the double wishbone front suspension with zero scrub radius and anti-dive, as well as numerous passive safety innovations.
Mercedes-Benz 300 SD turbo diesel (116 series), USA version, model year 1977.
In May 1978 the Mercedes-Benz 300 SD (116 model series S-Class) was the world's first series-production car with a turbocharged diesel engine, and also the first diesel-powered luxury-class car. It developed 85 kW (115 hp), and was only marketed in the USA and Canada. Its fuel consumption of 10.6 litres per 100 kilometres was around 30 percent lower than that of alternatively available petrol models. Compared with the naturally aspirated engine, the turbocharged variant also developed around 40 percent more output while maintaining the same fuel consumption.
Mercedes-Benz S-Class from the W 112, W 109, W 116 and W 126 series (left to right) on the test track at Stuttgart-Untertürkheim.
116 model series S-Class Saloon (1972 to 1980), exterior. Photo of a 450 SEL 6.9 produced in 1980, taken in 2005.
Drive unit for the world’s fastest sedan in its day: Engine of the Mercedes-Benz 450 SEL 6.9 of 1975.
Comparison of engines: Mercedes-Benz 280 S and 350 SE/350 SEL of 1973.
Mercedes-Benz 450 SEL 6.9 (W 116 series, 1972 to 1980), year of manufacture 1975.
116 model series S-Class Saloon (1972 to 1980), vehicle interior. The increase in on-board systems for greater safety and comfort also required new, ergonomic solutions: for the first time, a mounting support was installed beneath the dashboard to house the slide switches and controllers for the heating and ventilation, as well as the radio. Photo of a 450 SEL 6.9 produced in 1980, taken in 2005.
116 model series Mercedes-Benz S-Class Saloon (1972 to 1980), photo taken in 1972.
Mercedes-Benz 350 SE (116 model series S-Class, 1972 to 1980).
Mercedes-Benz 280 S, 280 SE, 350 SE and 450 SE sedan, 1972
Mercedes-Benz 280 SEL and 350 SEL model year 1973, 450 SEL model year 1972, 450 SEL 6.9 litres model year 1975
Mercedes-Benz 280 S sedan, 1972
116 model series Mercedes-Benz S-Class Saloon (1972 to 1980), headlamps with optionally available headlamp wiper system.
Mercedes-Benz 450 SEL, W 116 series
Mercedes-Benz engine 450 SE resp. 450 SEL sedan, 450 SL roadster resp. 450 SLC coupe, 1972
Mercedes-Benz 450 SE sedan, 1972
116 model series Mercedes-Benz S-Class Saloon (1972 to 1980), control elements.
Mercedes-Benz 350 SEL, W 116 series
Mercedes-Benz 450 SEL (W 116): The W 116 series was built from 1972 until 1980.
Diesel for America: The Mercedes-Benz 300 SD Turbodiesel (1977) was exclusively built for export to the USA and Canada.
Mercedes-Benz 450 SEL 6.9 (116 model series S-Class, 1975 to 1980), photo taken in 1975.
Mercedes-Benz 450 SEL 6.9 (W 116 series, 1972 to 1980), year of manufacture 1975.
Mercedes-Benz 280 SEL and 350 SEL, 1973, 450 SEL, 1972 and 450 SEL 6.9, 1975.
Mercedes-Benz 450 SEL 6.9, 1975.
Mercedes-Benz 450 SEL 6.9 (W 116 series, 1972 to 1980), year of manufacture 1975.
Mercedes-Benz S-Class saloons (model series 116) at the test track in Stuttgart-Untertürkheim, 1978. The upper vehicle with anti-lock braking system (ABS) remains steerable, while the lower vehicle without ABS continues to slide uncontrollably, despite the front wheels being at full lock.