The Mercedes-Benz W126 S-Class, launched in 1979, truly cemented Mercedes-Benz’s reputation as a maker of top-tier luxury vehicles. While its predecessor, the W116, had already established the brand’s prowess in safety and engineering, the W126 generation elevated the S-Class to a lasting symbol of sophistication and affluence throughout the 1980s and into the early 90s. Among the distinguished models in this lineup, the 1990 Mercedes 300 Sel stands out as a compelling example of this era’s automotive excellence.
The design philosophy behind the W126 marked a shift towards aerodynamic efficiency and improved fuel economy. Its streamlined silhouette boasted a 14 percent reduction in drag compared to the W116, and with a starting weight of around 3,600 pounds, the S-Class, particularly in its six-cylinder and diesel configurations, was notably efficient for its time, especially when juxtaposed with the large American sedans of that period. Safety remained paramount, with features like a driver-side airbag becoming available during the model run and a passenger airbag introduced in 1989, becoming standard in the 1990 Mercedes 300 SEL. Furthermore, advancements like traction control and seat-belt pretensioners were also incorporated, underscoring Mercedes-Benz’s commitment to occupant safety.
This image showcases the aerodynamic side profile of the Mercedes-Benz W126 S-Class, highlighting its sleek lines and sophisticated design from the 1980s.
For the American market, the W126 S-Class can be broadly categorized into two periods: 1979-1985 and 1986-1991. Initially, the U.S. received the V-8 powered 380SE/SEL and 500SEL models. However, a significant mid-cycle refresh in 1986 brought about the introduction of the inline-six cylinder 300SE/SEL, alongside the 420SEL and the flagship 560SEL (V-8). Coupe versions, designated as SEC, were offered in 380 and 500 forms initially, followed by 420 and 560 variants post-refresh. It’s worth noting that the earlier 380 models, and even the 420 to some extent, were often considered to be hampered by emissions controls. By 1986, the 300 models, including the 1990 Mercedes 300 SEL, delivered performance that felt comparable to the U.S.-spec 420.
Diesel engines also played a substantial role in the W126’s sales success. From 1980 to 1985, the U.S. market saw the five-cylinder 300SD, succeeded by the six-cylinder 300SDL in 1986 and 1987. Continuing the diesel legacy, the 350SD and 350SDL models were introduced in 1990 and 1991. While the 1990 Mercedes 300 SEL itself was a gasoline model, this context highlights the diverse engine options and market appeal of the W126 range.
A front-angle view of the Mercedes-Benz W126 S-Class emphasizes its iconic grille, flush headlights, and robust stance, features prominent in the 1990 models.
The mid-cycle update that refined the W126, impacting the 1990 Mercedes 300 SEL and other models, brought not only more potent engines but also visual and interior enhancements. The 1986-91 models are identifiable by their sleek, flush-face halogen headlamps with integrated headlight wipers. Inside, these updated S-Class vehicles boasted electronic automatic climate control, an electronically adjustable steering column, and refined leather trim on the steering wheel and shift lever. Luxury appointments like heated front seats were standard on the 560SEL and 560SEC and optional across the rest of the range, including the 1990 Mercedes 300 SEL. For the ultimate in rear passenger comfort, a two-place interior option, featuring power-adjustable rear seats, became available for the first time on the 500SEL and 560SEL models, accompanied by a burl-walnut center console and plush Arametta (suede-like) leather upholstery. These luxurious touches were indicative of the S-Class’s positioning as a flagship luxury sedan.
Mechanically, the powertrains of the Mercedes W126 models, including the engine in the 1990 Mercedes 300 SEL, are renowned for their robustness, often exceeding 200,000 miles without significant issues. Engines frequently outlasted transmissions, a testament to their engineering. While front-end and steering components and bushings would typically require replacement sooner, routine maintenance was generally no more complex than other European cars of the era. However, parts costs could be a factor in overall ownership expenses. The vacuum-operated power locks could sometimes present intermittent operational quirks, and the climate control systems, while advanced for their time, might not match the effectiveness of contemporary systems or even those in American luxury cars of the same period, and could be complex and costly to repair.
The interior of a Mercedes-Benz W126 S-Class showcases the luxurious appointments, including leather upholstery, wood trim, and electronically adjustable features typical of the 1990 300 SEL.
Diesel engines in the W126 family generally exhibited even greater longevity than their gasoline counterparts. However, fuel-system issues could arise in colder climates or with infrequent use. It’s worth mentioning that the 350SD and SDL diesel models haven’t always enjoyed the same reputation for reliability as other W126 diesels due to reported problems with bent connecting rods and cracked cylinder heads in certain years. For all later diesel models, engine mount replacement is considered essential. Furthermore, owners of 1986 and 1987 300SD California-emissions models should ensure that the original particulate filter has been replaced with an oxidation catalyst if it hasn’t been already. While these diesel engine notes are not directly related to the 1990 Mercedes 300 SEL (a gasoline model), they provide a broader understanding of the W126 engine range and potential maintenance considerations for different variants.
The S-Class, in general, became somewhat of an emblem for the U.S. gray-market importation phenomenon during the mid to late 1980s. Models like the 500SE and 500SEL, considered top-tier within the W126 lineup from 1985 to 1991, were not officially sold in the U.S. by Mercedes-Benz USA in those specific configurations. This, coupled with a perceived limitation in features and finishes offered through the official U.S. network, motivated dealerships and individuals to import approximately 22,000 vehicles through unofficial channels. The 1990 Mercedes 300 SEL, while part of the official U.S. lineup, benefited from the overall desirability and prestige of the W126 S-Class, making it a sought-after luxury sedan in its own right.
In conclusion, the 1990 Mercedes 300 SEL represents a high point in the W126 S-Class lineage. It embodies the advancements and refinements introduced during the mid-cycle update, offering a blend of refined inline-six cylinder performance, luxurious features, and the renowned build quality that defined Mercedes-Benz in that era. For enthusiasts of classic luxury cars, the 1990 Mercedes 300 SEL remains a compelling and iconic choice, reflecting a golden age of German automotive engineering and design.
