History

Development of the W140 began in 1981, with official introduction originally set for September 1989. Several different design proposals were studied from 1982 until 1986, when a definitive design proposal by Olivier Boulay was selected on 9 December 1986. Several engineering prototypes were evaluated from early 1987, with the final exterior design locked in September 1987. The design patents were filed on 23 February 1988 in West Germany and 23 August 1988 in the United States. ^[4] The lead designer Bruno Sacco attributed Jaguar's XJ40 sedan and BMW's E32 7-Series as a major influence on the W140's design. ^[5] [6] The initial exterior design proposal called for the two different cooling grille designs to denote the lower and upper model, similar to the idea of round and rectangle headlamps on the W123 (1976-1985). Innovative metal-forming technology allowed the extension of the engine hood/bonnet to the front bumper, with the grille placed inside the extruded metal. The W140 became the second model after the R129 (1989-2001) to have this extruded metal grille.

When BMW introduced a new 7-Series (E32) in 1986, the first post-war German passenger V12 engine (M70) was offered. This surprise announcement forced Mercedes-Benz to delay the introduction of the W140 by eighteen months to 1991. The delay allowed Mercedes-Benz to develop the new V12 engine and to rearrange the engine bay to accommodate the larger V12 engine, along with upgrading the brake system. The final development prototypes were completed in June 1990, with pilot production models being built from June 1990 to January 1991.

The project's cost overruns and eighteen-month delay resulted in the departure of Wolfgang Peter, the chief engineer of Mercedes-Benz. ^[7] The price of a W140 was considerably higher than its predecessor, the W126 (up to 25 per cent), leading to slow sales during the recession of 1990-1994.

The slow sales of the W140 can also be attributed to a wave of Japanese luxury cars that were introduced before the W140 was launched. While the base price of a six-cylinder 300SE was $71,500 in 1992, the Lexus LS400 started at $44,300, the Infiniti Q45 started at $43,600, and the Acura Legend started at $28,800. This led many prospective W140 buyers to switch to its competitors due to their lower prices, lower maintenance costs, better reliability, and in the case of the LS400, an ownership experience that was just as good, if not better, than its European competitors.

As a result of the price increases and stiff competition, Mercedes-Benz shifted from "engineer's design" to "market-driven design" in the 1990s. Many enthusiasts argue that the W140 was the "last true S-Class," as its successor, the W220, was criticized for having inferior engineering, and in the case of early models, poor reliability.

Two engines, a stillborn V16 engine based on an elongated V12 engine and an 8.0 W18 engine ^[8] meant for a hypothetical 800 SEL/S 800 were, again, developed in response to the purported rumour of BMW exploring a V16 engine and testing it in a 7-Series (E32) mule, named Goldfisch V16. The W18 did not proceed past the blueprint stage, but Mercedes-Benz had a small fleet of 85 W140 prototypes with V16 engines. Due to the increasing concern for climate protection and fear of sending a wrong message to the public in the early 1990s, the V16 engine was quietly cancelled. ^[9]

In March 1994, the updated W140 was unveiled at the 1994 Geneva Auto Salon and went on sale in April 1994.

In 1995, the two tone exterior appearance was made to be monotone, low-beam xenon headlamps were added and the rear indicator lenses became clear. The change was later introduced in June 1996 as 1996.5 models in Europe and 1997 models in the United States.

Safety

The W140 S-Class introduced noted safety innovations. ^[13]

• Braking system. The V8 and V12 W140 models distributed more braking power to the rear wheels, increasing stopping effectiveness. In 1996, the W140 received Brake Assist System BAS, which engaged during emergency maneuvers to boost braking power to maximum. ^[14]
• Electronic Stability Program (ESP) was introduced in 1995 on the Mercedes-Benz S 600 Coupé. ^[15] ESP used on-board computers to improve vehicle handling response during difficult driving conditions. This was a Mercedes developed system, which has since been licensed to other manufacturers.
• Xenon High-intensity discharge headlights (low beam only) were introduced in 1995.
• Side airbags and seat occupancy sensors were introduced in 1996.
• Automatic windscreen wipers with rain sensors were introduced in 1996.

C140 Coupe

In January 1992 Mercedes launched the C140 coupe at the Detroit motor show and only a couple of months later at the Geneva motor show. The USA was considered the priority market, hence the initial launch there. Along with the saloon this was intended to be a technical tour de force. Initially it came with just two engine choices with a third added at the 1995 face lift, the 5.0 litre M119 V8 engine and the 6.0 litre V12 engine, later at the face lift there was a third option of a 4.2 litre version of the venerable M119 V8 engine. Initially gearboxes were the same 4 speed automatic as in the saloon, however, this changed over to a 5 speed automatic at the facelift launched in 1995.

In the early years the C140 was badged either as a 500 SEC or a 600 SEC. With the 1995 facelift this changed with the introduction of the new engine so we had CL 420, CL 500 or the CL 600. There was another ‘freshen up’ of the model in the final year of production and this became the S 420 Coupe, S 500 Coupe and lastly the S 600 Coupe. However, the designation Coupe was not added to the badging on the boot lid