It has been 16 years since Mercedes (DAI) last offered a diesel-powered version of its flagship S Class sedan in the U.S. That situation is about to change with the arrival in Mercedes showrooms of the new 2012 S350 BlueTEC, which is powered by a 3.0-liter, 240-horsepower, diesel-powered V6 that produces an incredible 455 lb. ft. of torque. There’s no way of knowing if the new model will win over a significant percentage of S Class buyers, but it should.
Mercedes’ new sedan is the second-cheapest model in the S Class lineup (only $700 more than the S400 Hybrid), yet it is far more fuel-efficient than any of the others, including the hybrid. In other respects (size, available options, etc.) it’s identical to Mercedes’ flagship gasoline-powered S550 sedan, so you give up very little by opting for the diesel engine. In fact, you’ll barely be aware that the new model is powered by diesel. There’s no hint of the annoying smoke, fumes, and engine noise that once plagued diesel engines.
The new model also has two big advantages over the S550, which is powered by 429-horsepower V8. The first is that the S350 BlueTEC comes standard with all-wheel drive yet starts at just $93,425, well under the base price of $98,375 for the 2012 S550 4Matic and $95,375 for a rear-wheel drive S550. The new diesel-powered model also is rated to get 21 miles per gallon in the city and a remarkable 31 on the highway, for an average 25 mpg. That’s 8 mpg better, on average, than the S550 4Matic and 4 mpg better than the S400 Hybrid.
The S350 BlueTEC doesn’t yet have government crash test ratings. but like other Mercedes, it comes loaded with safety equipment, including front and rear head-protecting and rear side airbags, seatbelt pretensioners, brake dryers, stability and traction control, and pre- and post-collision safety systems. A night vision system is offered as a $1,780 option.
Total U.S. sales of the S Class fell 8.7 percent, to 8,877, in the first nine months of this vs. the same period last year. That’s a relatively strong performance, however, considering the state of the economy. During the same period, U.S. sales plunged 20.5 percent, to 7,750, for the BMW (BMWA) 7 Series and 23.4 percent, to 6,372, for Toyota’s (TM) Lexus LS. The biggest threat to Mercedes’ No. 1 position could eventually be Volkswagen’s (VOW) new Audi A8, whose U.S. sales soared 541.9 percent, to 4,179, during the first nine months of this year.
Behind the Wheel
The main thing you give up by opting for the diesel engine—actually just about the only thing you give up—is raw speed. The S350 BlueTEC is rated to jump from zero to 60 in 7.0 seconds, a tad quicker than the S400 Hybrid’s 7.2 seconds. Both trail way behind the S550, which sprints from zero to 60 in a mere 5.4 seconds. I would guess, however, that the S350 BlueTEC is plenty quick for many S Class owners. If you’re really into spirited driving, you probably would be better off with the BMW 750i anyway.
Mercedes’ new diesel shares the strengths and weaknesses of the gasoline-powered S550. These are luxury cars in the traditional sense of the term. The ride is very smooth, though a little boaty for my taste—and noticeably squishier than a BMW 7 Series. The brakes also don’t bite as hard as they do in the BMW. There’s a slight hesitation when you punch the fuel pedal, but the car accelerates smoothly after that.
The cabin remains quiet at all speeds. The only time you hear the rasp of the diesel engine is when you accelerate at a relatively low speed. Even then, the sound is so muffled you barely notice it. The engine’s massive torque means there’s lots of power for accelerating onto a freeway or moving out into the passing lane.
The diesel engine requires virtually no extra maintenance, Mercedes says. The main thing you have to do is top off the AdBlue reservoir, AdBlue being a chemical solution essential to reducing emissions from the diesel engine. The dealer can do this during regular maintenance visits, or the owner can do it. It’s only slightly more complicated than topping off a car’s windshield wiper fluid, the main difficulty being that the AdBlue reservoir is under the spare tire, so you have to remove the spare to get at it.
One negative about the Mercedes S Class is the company’s overly complicated Comand control system, under which the radio, navigation system, and other instruments are operated largely by manipulating a round control knob on the center console. Audi’s system, which combines screen commands with a number of buttons, is much easier to use.
Buy It or Bag It?
BMW, Audi, Lexus, and Jaguar don’t offer a diesel-powered, high-end luxury sedan in the U.S., so the Mercedes is the only game in town. Even so, Mercedes expects only 5 percent to 10 percent of S Class buyers to opt for the S350 BlueTEC. That’s about the percentage of E Class buyers who opt for diesel power.
I’ll never understand why more Americans don’t opt for diesel power. You don’t give much, and you not only get significantly better fuel economy but pay five grand less than you would for a comparable gasoline-powered Mercedes S550. Keep in mind that the S550 and other big luxury cars use expensive premium gasoline. Diesel prices are volatile, and but diesel rarely costs more than premium gas, so you should save thousands in fuel costs over the life of the car. Seems like a no-brainer to me.
Click here to see more of the 2012 Mercedes-Benz S350 BlueTEC.