The S350: Hardly Granddad’s Diesel

By Bill Griffith, NEMPA

To some, putting a diesel powerplant into the Mercedes-Benz S-Class is heresy. But a few current owners–Mercedes executives expect that they will make up 5 to 10 percent of buyers–are reacting with, “It’s about time.” Mercedes-Benz’s Eric Linder, assistant product manager for the S-Class, feels there’s a knowledgeable customer base with experience in prior M-B diesels, a group that’s been waiting for a car such as this. However, Americans in general are unfamiliar with modern, “civilized” diesel-powered passenger cars, so Mercedes-Benz brought a fleet of its new S350 sedans to Boston in late October for a show-and-tell. NEMPA members were there on behalf of their media, and Bill Griffith covered the event for both and


The new diesel-powered S350 has all the traditional stance and authority of the Mercedes-Benz S-Class.

The present S-Class has been around since 2006, but it’s still the segment leader in sales and many owners call it the finest automobile made. The diesel engine, introduced by Rudolf Diesel in 1893, first went into volume production with Mercedes-Benz in 1936 with the 260D–a 2.5-liter engine with 45 horsepower. (No 0-to-60 time because its top speed was 59 miles per hour). In 1977 Mercedes came out with the 300SD, the first production turbocharged diesel. That vehicle was, automotively speaking, nearly indestructible, given minimal maintenance; and it demonstrated all the negatives that many Americans still associate with diesels. It clattered, belched blue smoke, and left soot and a smelly exhaust in its wake. Due to more stringent emission regulations here than in Europe, Mercedes phased out diesels in the US in 1995, after the 350SD.

But now they’re back. And they don’t look any different from the most popular S-Class, the S550 sedan, other than the badge. However, there’s a big difference under the hood. The S350 is powered by a 3.0-liter V-6 BlueTEC turbodiesel that produces a modest 240 horsepower but a whopping 455 lb.-ft. of torque. The BlueTEC exhaust system has an oxidizing catalytic converter and a particulate filter, and then breaks down its emissions into nitrogen and water vapor by injecting a urea solution called Adblue into the tailpipe. Adblue is stored in a seven-gallon tank under the spare tire, which needs refilling about every 10,000 miles. (The tank, not the tire.)

Mercedes-Benz emphasized that both this new diesel S-Class and its S400 Hybrid gas-electric variant have exactly the same interior room and luxury and convenience as all S-Class vehicles.

NEMPA’s Cliff Atiyeh joined me for a drive around town in a silver S350. It had a stunning deep-cocoa and black leather interior that was the equal of any I’ve ever seen, especially with the white-on-black electroluminescent S-Class gauges. You had to listen closely–with the $6,400 Bang & Olufsen BeoSound audio system off–to hear just a hint of clatter on a few occasions when the engine lugged slightly. We saw no smoke. We did notice mild turbo lag when jumping hard on the throttle.


It is every inch a top-line Mercedes-Benz on the inside as well, with the same space, luxury and convenience as all S-Class vehicles.

All S350s are equipped with M-B’s 4Matic AWD system. Power goes to all four wheels through an advanced seven-speed automatic transmission that uses a low-viscosity, low-friction transmission fluid (colored blue instead of red). Eric linder said the diesel S-Class should achieve 21 miles per gallon in city driving, 31 on the highway, and 25 combined. And this diesel sprints to 60 mph in about seven seconds.

Lead Photo: Zane Merva
Story Photos: Mercedes-Benz

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