The Mercedes-Benz W140 is a series of flagship vehicles that were manufactured by the German automotive company Mercedes-Benz from 1991 to 1998. On November 16, 1990, Mercedes-Benz unveiled the W140 S-Class via press release, later appearing in several February and March editions of magazines. The W140 made its public debut at the Geneva Motor Show in March 1991, with the first examples rolling off the production line in April 1991 and North American examples on August 6, 1991. Short (SE) and long (SEL) wheelbase sedans were offered initially, as well as the coupé (SEC = S-Klasse-Einspritzmotor (Fuel injection engine)-Coupé) body style C140 from October 1992. Like all Mercedes-Benz lines, the W140 S-Class was rationalized in late 1993 using the new "letter-first" nomenclature. The SE, SEL, and SEC cars were renamed the S-Class, with alphanumerical designations inverted. For example, the 500 SE became the S 500, and the 500 SEL became the S 500 L. In 1996 the coupé models following a mid-life update were separated into the CL-Class. The W140 series S-Class was superseded by the W220 S-Class sedan and C215 CL-Class coupe in 1999 after an eight-year production run. Mercedes-Benz built 432,732 examples of the 140 series, comprising 406,710 sedans and 26,022 coupés.
As with its predecessor, the W126, the W140 was the first of the "next generation" of Mercedes-Benz models to feature the company's new design theme. This design was adopted for the new C-Class in 1989 and during 1991 for use on the facelifted W124 in 1993. Development on the W140 began in 1981, originally set for an October 1989 production start. From 1982 to 1986 several designs were reviewed, until December 9, 1986 when a definitive design by Olivier Boulay was approved. Several prototypes were tested onwards from early 1987 and the final production exterior design was frozen in September 1987, with domestic design patents being filed on February 23, 1988 and U.S. patents six months later on August 23. The design was said by lead designer Bruno Sacco to be influenced by Jaguar's XJ40 sedan and BMW's E32 7-Series. Before production started, the exterior appearance of the W140 was revised in the form of the grille on all W140s being recessed as opposed to a planned exclusive grille on the top model, a feature which later spread to the rest of the Mercedes-Benz range. In 1987, an 18-month delay was made from 1989 to 1991 to accommodate a V12 engine and a high-performance braking system. This resulted in the final development prototypes being completed in June 1990. Pilot production models were made from June 1990 to January 1991.
The W140 introduced innovations such as double-pane window glazing, power-assisted closing for doors and trunk lid, electric windows which lowered back down upon encountering an obstruction, rear-parking markers which rose from the rear wings (discontinued on later vehicles, and replaced with sonar-assisted parking) and a heating system which, if desired, continued to emit warm air after the engine was turned off. For details like this, the W140 is often known as the last Mercedes to be "over-engineered," a Mercedes trait that was costing the company in product delays and overbudgeting. According to Motor Trend, this action reportedly caused project cost overruns and resulted in the departure of Wolfgang Peter, Daimler-Benz's chief engineer. The vehicle is believed to have cost Mercedes-Benz over $1 billion to develop. For the consumer, the W140 cost a considerable 25 percent more than its predecessor, the W126.
Mercedes Benz W140 Sedan (April 1991 – September 1998)
Mercedes Benz W140 Coupe (October 1992 – September 1998)
Source: WIKIPEDIA