It probably will surprise no one when I say that travelling in a Mercedes-Benz S-class is a pretty swell experience. The stretch-out-spacious cabin is lined with soft leather and burnished with glossy wood and metal trim. Electronic servants are on hand to assist with most any task, be it closing the trunk, moving the steering column, or raising the blinds over the rear windows. The chassis is poised and the steering is creamy yet direct. Cruising is hushed, and the powertrain is responsive.
Particularly given those last two points, it might surprise a lot of people, if they had the opportunity to drive the S350 BlueTEC I had recently, to learn that the car is powered by a diesel engine. The 3.0-liter V-6 in the S-class has reached the point of such refinement that the only time you'd ever suspect it's a diesel is if you're standing outside the car with the engine running. From inside, you barely hear it.
With 455 pound-feet of torque available from an ultra-low 1600 rpm, off-the-line response is excellent. Stomp on the gas when you're already cruising along though, and this S-class doesn't rocket ahead the way its V-8 counterparts do. Still, a 7-second 0-to-60 time is plenty adequate for this heavyweight cruiser.
But where a V-8 S-class drinks gasoline like, well, a heavyweight cruiser, the diesel version sips fuel like a car several sizes smaller. I took the big Benz up to Massachusetts for a day of skiing, and averaged an indicated 33 mpg on the 200-mile round trip, which was a gentle mix of parkway driving and country two-lanes. It is hard to imagine a more luxurious way to get 33 mpg.
The S350 Bluetec's mileage is even more amazing when you consider that the car is four-wheel drive (4Matic standard here). Even using the EPA ratings of 21/31 mpg as a basis of comparison, the S350's highway mileage beats nearly every four-wheel-drive SUV and crossover, even pint-sized models like the Nissan Juke and Mitsubishi Outlander Sport. The one exception is the Mini Cooper S Countryman All4 (manual), which it ties. City fuel economy isn't quite the same story, though, with the Mercedes' 21 mpg easily exceeded by several small AWD crossovers and by the hybrids.
Speaking of hybrids, the S-class is also offered in hybrid form. But it's hard to see the advantage of it. The S400 Hybrid, which is rear-wheel-drive only, is rated at 19/25 mpg, so the diesel not only beats it on the highway but in the city as well. The Hybrid is $700 cheaper, but that hardly seems significant when the pricing of both models starts on the high side of $90,000.
Although diesel-engine S-class cars were once common in the United States, they have been gone from the U.S. market since 1996. The S350 BlueTEC joins the lineup for 2012, and it will be interesting to see how well American buyers accept it. With unimpeachable luxury bolstered by all-weather capability and surprising economy, it certainly seems like the smart-money choice among big-money Benzes.