The Mercedes-Benz W123 is a range of executive cars produced by German manufacturer Mercedes-Benz from November 1975 to January 1986. The W123 models surpassed their predecessor, the Mercedes-Benz W114, as the most successful Mercedes-Benz, selling 2.7 million units before production ended in the autumn of 1985 for the saloon/sedan versions and January 1986 for coupés and estates/station wagons.
Following a slow production build-up during the first year, customers who placed their orders faced a lengthy waiting period of nine to twelve months. A black market emerged for the customers who were willing to pay more for immediate delivery. The slightly used W123 commanded about 5,000 Deutsche Mark premium over its original sale price.
Like its predecessors, the W123 gained the reputation of being well built and reliable. Many taxi companies in Germany chose the W123 due to its reputation of durability and reliability. Reaching 500,000 or more kilometres with only minor mechanical issues was common with W123 used as taxicabs. Once the W123 reached the end of its service life, they were often shipped to Africa and third world countries where they were highly esteemed for their ability to travel on rough roads and to require infrequent maintenance.
W123 production ended in January 1986 with 63 final estates/station wagons rolling out. The most popular single models were the 240 D (455,000 built), the 230 E (442,000 built), and the 200 D (378,000 built).
Design The W123 shares technical similarities with its predecessors, including the engines, steering system, and suspension system. The design is updated with styling cues from its larger sibling, Mercedes-Benz W116, namely wider ribbed taillights, horizontal headlamps, front turn signal indicators on the outer edge, and pull-to-open door handles.
Friedrich Geiger was head of the styling department at the time the W123 design was finalized in 1973. Design goals according to chief engineer Hans Scherenberg included creating a "balanced, dynamic, non-aggressive form – one that lends these vehicles a special character – by emphasizing horizontal lines both at the front and rear, suggesting a slight wedge shape from the side aspect, reducing the use of chrome trim and, in the truest sense of the term, introducing rounded lines,” Scherenberg said. "We are as unimpressed by revolutionary leaps of style as by fashionable gimmicks."
The interior is revised with a larger instrument panel, central round ventilation outlets, HVAC control panel and a single row of control switches in the centre. The instrument panel has three large gauges placed behind a single plastic cover. The manual HVAC control panel has three large dials with the left and right for individual temperature control and the centre dial for fan speed control. Air flow is controlled by two sliders (left for upper zone and right for lower zone). If the optional air conditioning unit was ordered, a temperature roll dial was fitted to the row of control switches. The automatic HVAC control panel is simplified with a single roll disc on the left for temperature control, a row of push buttons in the middle for directing the air flow and switching the system on and off and a vertical set of buttons on the right for controlling the fan speed and switching automatic control on and off.
Initially, all models except the 280, 280 E, and coupé featured larger round headlamps with smaller round fog lamps with large glass plate covering the entire headlamp housing and acting as a diffusing lens. This design is the same for North American models with the sealed beam units and glass plate partially covering the headlamp housing. The 280, 280 E, and coupé models use large rectangular headlamps with round fog lamps. From 1983 onward, all models except for the aforementioned North American models featured the rectangular headlamps. The headlamp washers and wipers set are optional.
Nomenclatures Per Mercedes-Benz tradition (prior to the 1993 rebranding), model designation corresponded to the engine displacement, chassis type (coupé or estate/station wagon), fuel type (for diesel engines only), and availability of fuel injection system for petrol engines:
W for Wagen (Sedan) C for Coupé T for Tourismus und Transport (estate/station wagon)
No designation was given for the long-wheelbase: it was simply called "Lang" (long) in the brochures and order forms.
D for Diesel E for Einspritzung (fuel injection)
When the diesel engine is turbocharged, an emblem that reads "TURBODIESEL" is affixed to the right side of the boot lid.
As for the chassis codes, W123 is the sedan, S123 the estate, C123 the coupé, V123 the long-wheelbase sedan a.k.a. Lang, and F123 refers to the bare long-wheelbase chassis as used for ambulances and other conversions.
Model variations Saloon (W123) The four-door version went on sale on 29 January 1976.
Coupé (C123) In the spring of 1977, a coupé version was introduced on a shortened wheelbase ( versus for the saloon). The C123 was available as 230 C (later 230 CE), as 280 C and 280 CE in most markets, and as the 300 CD/300 CD Turbodiesel for the US market. Unlike the W123 saloon, the rectangular headlamps were fitted to the C123 regardless of engine type.
Limousine (V123) From August 1976, a long-wheelbase version, extended to , with seating for seven to eight was produced. The limousine was built on a stretched W123 saloon/sedan chassis with additional lower side panels behind the rear passenger doors. The elongated roof has the same C-pillar form as on the saloon/sedan. The rear passenger doors were custom-designed in rectangular shape and of the same length as the ones on the saloon/sedan. The engine options were 250, 240 D, and 300 D. A few 280 E limousines were built as special orders.
Chassis (F123) The stretched limousine version was offered with complete front body clip (B-pillar forward) and strengthened chassis as the base for ambulances or hearses to be built by the conversion specialists such as Binz and Miesen. F stands for Fahrgestelle (chassis).
Estate (S123) At the 1977 IAA in Frankfurt, the brand's first-ever factory-built estate, S123, was introduced. The letter T in the model designation stood for Tourismus und Transport (Touring and Transport). Previous estates had been custom-built by the coachbuilders, namely Binz. S123 production began in April 1978 at Mercedes-Benz Bremen factory. All engines except the 2-litre version of the M115 (petrol) and OM615 (diesel) were available in the range. When the M115 was replaced with the new M102 engine, a petrol-engined 200 T also joined the range.
Convertible While Mercedes-Benz never built its own convertible, some, based on the C123 coupé, were built by external companies including Crayford in the UK which (using the folding soft-top assemblies from 1973 Ford Mustangs salvaged from wrecking yards, the dimensions of the mechanism being ideal) built the "St. Tropez" and Niko-Michaels in New York, USA. In the city of Hagen, Germany, until 2016, the small, family owned Bähr built C123 cabriolets, and also sold kits for the conversion.
Engines All of the W115's engines were carried over, including the 2.0- and 2.3-litre M115 four-cylinder petrol units, the 2.0- and 2.2-litre OM615 and 2.4-litre OM616 four-cylinders and the 3.0-litre, five-cylinder OM617 diesel engines.
The W114 motors, however, received a makeover: the M180-powered 230.6 and M130-powered 250 were replaced by the new, single overhead-cam, 2.5-litre M123, with the car badged as 250.
This meant that for the domestic market the M115 four-cylinder model dropped the .4 suffix for redundancy, and the OM617 powered model would receive nomenclature matching the engine displacement: 300 D instead of 240 D 3.0. Such badging had already been used for the previous generation on North American export models.
The flagship DOHC M110-powered, 2.7-litre motor was also carried over, available both as the carbureted 280 and with K-Jetronic as the 280 E.
In the autumn of 1978, the power output of the 240 D was increased from while the 280 E's power went from . In early 1979, the power output rose from to for the 200 D and from to for the 300 D. The 220 D was discontinued after 1979.
In June 1980, the new M102 four-cylinder petrol engine replaced the M115. The 2-litre version was only available with a carburettor while the 2.3-litre version was available with fuel injection only. The carbureted version of 2.8-litre M110 engine in the 280 and 280 C was discontinued in 1981, leaving the 250 as the sole carbureted six-cylinder engine.
The world's first turbocharged diesel engine for a passenger vehicle, the OM617 A, was finally introduced in W123 in September 1979 with 300 TD Turbodiesel that was initially exclusive for the European market. The same engine was offered in North America and Japan in 1981 as the 300 D Turbodiesel 300 CD Turbodiesel, and 300 TD Turbodiesel.
Some engines in the W123 were mounted with small shock absorbers in addition to industry standard motor mounts to reduce felt vibration and a provide a smoother ride. These designs were carried over from previous chassis models like the W114/W115.
Motorsport
One notable achievement was in the 1977 London–Sydney Marathon rally, where the 280 E won first and second, ahead of the third and fourth place Citroën CX.
North American sales North American sales began with the W123 sedan for the 1977 model year. The initial range consisted of the 230, 240 D, 300 D, and 280 E models. Compliance with stringent Environmental Protection Agency (EPA) automotive emission control regulations on performance and US Department of Transportation on passenger safety required extensive changes to the vehicles, that made them significantly different from those sold in Europe. When the S123 estate/station wagon was introduced in the US in 1979, the engine choice was limited to 3-litre OM 617 diesel engine. No 240 TD or 280 TE were offered.
Externally the changes were most noticeable with massive 5-mph front and rear bumpers and sealed-beam headlights. This particularly affected the 280/280 E models, whose European counterparts received elegant wrap-around chrome bumper tips and square halogen headlights, which were unavailable to US customers. Journalists reported that "the visual changes were on the mild side" compared to US version of the Mercedes-Benz R107 and Mercedes-Benz W116, which have been described as if a "beautiful car was beaten with the malaise ugly stick."
The W123 production coincided with the introduction of federal regulations on corporate average fuel economy (CAFE) and the amendments with the Clean Air Act, which mandated catalytic converters, lower compression ratios and exhaust gas recirculation. All of these measures affected the equivalent weight and performance of the imported cars. For example, the European 280 E had a 1460 kg curb weight and its engine had a DIN rating of at 5800 rpm and at 4500 rpm. The corresponding North American car ranged between depending on the model year and state (California received different specifications for 1977 and 1978) while weighing at least more than its European counterpart.
As the regulations were less stringent on diesel engines, Mercedes-Benz saw this as a way to circumvent the restrictions. In 1981, the turbocharged diesel engine became the sole engine choice for 300 D, 300 CD, and 300 TD. The 300 CD and later 300 CD Turbodiesel were exclusive to the US market and not offered elsewhere, including Europe where the taxation is favourable for the diesel fuel.