The Star® Journal

The first Mercedes-Benz model range to be officially designated as the S-Class, these beautifully built modern automobiles were all but ignored for decades

Article Richard Simonds
Data tables Daniel Stahl
Images Daimler Archives

The W116 is one of the most polarizing Mercedes-Benz series ever built in Sindelfingen. Bruno Sacco's modern, angular design was one contentious factor; the technical challenges presented by the negative effect of mandatory emissions controls on drivability was another. Enthusiasts of the W108-W109 regard the W116 as a guinea pig forced to meet the safety and environmental issues of the 1970s; others prefer the later W126 series from the 1980s. Constantly changing U.S. emissions and safety requirements in the 1970s meant that Mercedes-Benz in effect used the W116 as a rolling test bed for evolving engine specifications, suspension tuning and emissions technology. These ongoing adaptations included catalytic converters (added to U.S. models in 1975), automatic climate control (added 1976, all models), the four-wheel selective leveling system (1976, on the 6.9), the turbodiesel engine (1978) and K-Jetronic fuel injection (1976, all gasoline V-8 models). The darkest days of the model's plight are exemplified by the 1975 and 1976 280S, which relied on a low-compression version of the M110 twin-cam six to generate 120 horsepower, while returning a paltry 12 mpg at anything over 70 mph.

The W116 was given a new lease on life by the introduction of the breakthrough 300SD in 1978. The turbodiesel era of Mercedes-Benz automobiles had finally arrived, and as a result, most of the W116s available today are diesels. However there are still plenty of examples of the 280SE, 450SE/SEL and even the 280S, still available for enthusiasts. In spite of the challenges in the 1970s, Mercedes-Benz vehicles of the time did not suffer the “malaise era” epithet that dogged so many American cars because of their terrible performance and poor drivability.

Background

With the international oil crisis and growing environmental concerns, the 1970s were an era of great turmoil in the automotive industry. Launched to high public expectation despite this uncertain economic climate, Mercedes-Benz designed the W116 as the successor to the robust and popular W108 and W109 series.

The W116 first came to the United States in 1973. There was never a 1972 version, not even in Europe - the predecessor W108 wasn't phased out until September of 1972, a rare instance of a delayed model launch in Stuttgart. One of the earliest W116s tested by Road and Track was built in February of 1973. The launch range in Europe consisted of the 280S, 280SE and 350SE. In March of 1973, the 450SE and 450SEL were introduced. These models remained the only models for the United States until the 280S came to America in 1975.

In 1976 all V-8 models were updated with hydraulic valve tappets and K-Jetronic injection. The automatic climate control system that Mercedes-Benz adapted from Chrysler was also standardized on U.S. models. Difficult to repair, this system has somewhat clouded the reputation of the 1976 and later W116s.

The 450SEL 6.9, officially called simply “6.9” in the U.S., was introduced as a 1976 model in Europe; an American version followed in 1977. The 280S was replaced in 1977 by the stronger, faster 280SE, when the 450SE was discontinued in the United States. In 1978, interest in the W116 was revived by the 300SD, which, while not being as fast as a 450SEL, was capable of 25-30 mpg. Production of this model continued into August of 1980, with almost 29,000 examples manufactured.

The majority of W116s were phased out in Europe during the 1979 model year, but production for the American market continued into 1980.

Few major model changes occurred during the life of the W116. The first major revision came in the summer of 1973 for the 1974 model year, with the addition of larger bumpers to meet recently instituted federal standards requiring vehicles to survive five mph collisions without damage to lights, safety equipment or engines. The W116 engines and climate control systems also received major updates in 1976.

Today, many W116 buyers are new to classic Mercedes-Benz ownership, and see the model as elegant and with an airy cabin offering greater visibility than modern cars. Sacco's angular design has caught the eye of a younger generation that appreciates both the build quality and image of these cars. The 6.9 and 300SD have their own cult followings; the 6.9 has found an especially enthusiastic reception in the last few years. Much like the 300SEL 6.3 that preceded it in the W109 series, the 6.9 was the “gentleman's hot rod” of its day.

Reasons to buy a W116

• Consistent build quality, even on 1975-1976 emission-era cars.
• Mechanical robustness.
• Long driveline and suspension life.
• Bumpers could exceed the required 5 mph impact.
• Comfortable M-B Tex or leather upholstery interiors.
• Increased interest from the collector car community.
• Access to service literature and mechanical parts supply.
• Cheaper to purchase and service than a W108 or W109.
• The 300SD has bulletproof build quality and diesel economy.

Reasons not to buy a W116

• Poor fuel economy on gasoline models.
• Emissions headaches on 1975-1976 U.S. market examples.
• Automatic climate control systems are challenging to repair.
• Difficulty of finding interior and exterior parts.
• Not as good as the W126 that replaced it.
• Stubborn sellers with unrealistic expectations.

Checkpoints

• Front and rear glass seals often in need of replacement.
• Transmission leaks at the front seal.
• State of driveshaft flex discs, engine mounts, driveline parts.
• Leaking steering gear boxes.
• Excessive steering column play indicates bad steering coupler.
• Road test 6.9 hydraulic suspension for leaks, bouncing ride or other strange behaviors.
• Rebuilding the hydraulic suspension on a 6.9 is expensive.
• Engines, whether M110, M116, M117, or the OM617, are all quite robust and long lived.
• The V-8 models may need timing chains and upper chain rails.
• The 6-cylinder engines usually require a gasket between the cylinder head and the camshaft carrier-bearing box.
• With the exception of V-8 engines after 1975, all engines require regular valve adjustment.
• Oil consumption should be assessed, as valve guides and seals are common wear items on gasoline engines.
• Trunk wells often rust due to water collection.
• Floor pans rust especially towards areas that are low enough to collect water.
• Rust at extremities of firewall, as well as around the fuse box.
• Check for rust in the sunroof tray if sunroof equipped.
• Rust in the bottoms of the doors is also possible.
• Rust in the rocker panels is a common problem in coastal cars and cars from severe winter states.
• Rust is often found around the shock towers, under the brake booster, and under the climate control servo on cars that have not been cleaned or garaged.
• Rust can hide in the cowl under the cowl vent grill due to drainage issues.
• Front control arm bushings, ball joints, steering linkages, and worn upper control arms.
• Rear sub-frame bushings and rear control arms can be worn and/or rusty.
• Condition of driveshaft flex discs and engine mounts, as well as other rubber driveline parts.
• Leaking steering gear boxes.
• Transmission leaks at the front seal.
• Interior panels, such as door panels, roof rail panels, center console, dash, etc. are prone to fading and cracking. These are not available new, and used ones are hard to find.
• Automatic climate control systems almost always need some kind of repair, however new replacement servos and vacuum actuators are still available.
• Woodwork is often faded and lackluster. Refinishing is a challenge due to difficulty of removing the trim for refurbishing.
• Front or rear seats on early W116 can look flat, meaning excelsior pads have failed. Replacement kits cost over $3,000.
• Finding a seller with realistic price expectations.

Finally

Today, the W116 range is slowly gaining recognition with classic Mercedes-Benz enthusiasts. While these cars often require a fair amount of work to get in order again, a well-sorted W116 can be a delight to drive. Even the 280S, burdened with its catalytic converter and Solex carburetor, can still be a fun car to own and drive regularly. Like all classic Mercedes-Benz vehicles, these are usable, comfortable automobiles with excellent braking and handling. Driving one doesn't feel like a chore.

While W116 models are now recognized as outstanding examples of Mercedes-Benz build quality, market valuations haven't quite caught up. Although this can make a W116 a difficult sales proposition, the buyer of a carefully chosen example will quickly appreciate that the W116 is one of the best-kept secrets in the world of classic Mercedes-Benz ownership.

W116 450SEL 6.9 • 1975-1980

The W116 was launched in autumn 1972 as the company's flagship model; every aspect of the big sedan was new or improved. Upgrades included a modern double-wishbone front suspension

(1) for better handling and road holding, a central locking system (2), smooth automatic transmission (3), plus available tachometer (4) and headlight washer system (5). Bruno Sacco's angular design concealed a stronger passenger safety cell with high-strength roof, reinforced doors and door pillars to protect passengers in the airy cabin (6-7) with a padded dashboard, four-spoke safety wheel (8), and deformable switches (9). In 1975, the 450SEL 6.9, with its powerful 6.9-liter V8-engine (10) became the new top model of the W116 range.

Specifications: Mercedes-Benz W116 Sedans • U. S. Models • 1973-1980

MODEL	YEARS	CHASSIS	ENGINE	POWER (hp)	TORQUE (lb-ft)	TRANS	REAR AXLE	0-62 MPH	TOP SPEED	MPG
450SE	1973-1975	116.032	117.983	'73: 190 '74 Fed: 190 '74 CA: 180 '75: 180	'73: 240 '74 Fed: 240 '74 CA: 232 '75: 220	3A	3.07	11.5	121	16
450SE	1976	116.032	117.986	180	220	3A	3.07	11.6	118	16
450SEL	1973-1975	116.033	117.983	'73: 190 '74 Fed: 190 '74 CA: 180	'73: 240 '74 Fed: 240 '74 CA: 232	3A	3.07	11.5	121	16
450SEL	1976-1979	116.033	117.986	180	220	3A	3.07	11.6	118	16
450SEL	1980	116.033	117.986	160	230	3A	2.65	12.8	115	16
280S	1975-1976	116.020	110.922	120	143	4A	3.69	15.8	106	12-18
280SE	1977-1979	116.024	110.985	Fed: 142 CA: 137	Fed: 149 CA: 142	4A	3.69	14.4	112	15-18
280SE	1980	116.024	110.985	140	145	4A	3.69	14.4	112	15-18
6.9	1977-1979	116.036	100.985	250	360	3A	2.65	8.9	133	12
300SD Turbo	1979-1980	116.120	617.950	'79: 110 '80: 120	'79: 168 '80: 170	4A	3.07	17	103	22

Global W116 Chronology

• 1972 - September 280S, 280SE, 350SE introduced
• 1973 - March 450SE, 450SEL (100mm longer wheelbase) introduced
• 1973 - November 350SEL introduced
• 1974 - April 280SEL introduced
• 1975 - May 450SEL 6.9 introduced as a successor to the 300SEL 6.3
• 1975 - November Improvements to fuel-injection system to meet more stringent emissions regulations on 2.8-, 3.5-, and 4.5-
• 1976 - February liter engines (Bosch K-Jetronic replaced D-Jetronic). Transistorized, breakerless ignition system introduced.
• 1976 - April Automatic climate control system introduced on all U.S. models
• 1976 - September Four-wheel selective leveling system introduced on 6.9
• 1978 - May The 300SD (3-liter, 5-cylinder turbodiesel) is produced exclusively for the United States and Canada to offer a luxury sedan with high fuel efficiency to meet “Corporate Average Fuel Economy” (CAFE) standards
• 1978 - September Anti-lock brake system (ABS) introduced exclusively on the W116
• 1979 - September W126 model introduced
• 1980 - April - September W116 production phased out according to model. Final W116 off the assembly line was a 300SD

Global Production

• 280S - 122,848
• 280SE - 150,593
• 280SEL - 7,032
• 350SE - 51,100
• 350SEL - 4,266
• 450SE - 4,160
• 450SEL - 59,578
• 450SEL - 6.9 7,380
• 300SE - 28,634
• TOTAL = 473,035