Used 2012 Mercedes-Benz S-Class S350 BlueTEC 4MATIC® Diesel Review

The Mercedes-Benz S550 gets a new, more powerful and more efficient V8 engine for 2012. This year also sees the addition of a new member of the S-Class: the diesel-powered S350 Bluetec. It returns best-in-class fuel economy by a wide margin, and can theoretically go more than 700 miles on one tank of fuel.

Its competitors are impressive, but the 2012 Mercedes-Benz S-Class remains the quintessential premium luxury sedan.

High atop the sedan food chain sits one car: the 2012 Mercedes-Benz S-Class. Oh, you can buy more expensive sedans, but rarely will those cars match the pedigree of this iconic Benz. The S-Class has been at the forefront of automotive advancement for decades, showcasing new features in technology, safety, performance and general innovation for decades. As such, it is very much the standard-bearer for all others, and deservedly so.

The S-Class is more expensive than most similarly equipped flagship luxury sedans, but it doesn't take much time behind the wheel to realize that its higher price is commensurate with its higher degree of engineering, interior craftsmanship and even feature content. The S-Class also stands out with its variety of engine choices, particularly for 2012. With the S350 Bluetec model, a turbodiesel returns to the Mercedes flagship for the first time in 21 years. This time, however, it's a thoroughly modern unit with a prodigious output of 455 pound-feet of torque and no black smoke belching out the back. It also delivers substantially better fuel economy than the carryover S400 Hybrid.

That's not the only new engine. The S550 gets the same twin-turbo 4.7-liter V8 found in the CL- and CLS-Class, boasting more power and better fuel economy than the engine it replaces. It's hard to imagine needing any more power than it provides, but nevertheless, the S-Class still offers the V12-powered S600 and the AMG-tuned S63 and S65.

Quite frankly, if your new ultra-luxury-sedan search begins and ends with a 2012 Mercedes-Benz S-Class, you probably won't regret your decision. Having said that, the S-Class competes with an incredible group of fine sedans that includes the Audi A8, BMW 7 Series, Jaguar XJ, Maserati Quattroporte and Porsche Panamera. It's an impressive lot with which it's hard to find fault, but none of them can quite match the well-rounded and time-tested superiority of the S-Class.

The 2012 Mercedes-Benz S-Class is a five-passenger, full-size luxury sedan available in S400 Hybrid, S350 Bluetec, S550, S600, S63 AMG and S65 AMG trim levels. Each is representative of a different engine, and in the case of the AMG models, a higher degree of other performance capabilities.

Every model comes standard with 18-inch wheels, an adaptive air suspension, active bi-xenon headlights with automatic high beams and LED running lights, a power trunk closer and a sunroof. Comfort and convenience items include dual-zone automatic climate control, 10-way power front seats (with heating, ventilation, four-way lumbar adjustment and memory functions), leather upholstery and extended interior trim, a power tilt-and-telescoping steering wheel, auto-dimming driver-side and rearview mirrors and a power rear sunshade. Electronic features include the COMAND electronics interface, Bluetooth, a navigation system, voice controls and a 15-speaker Harman Kardon surround-sound audio system with a six-CD/DVD changer, HD radio, satellite radio and an iPod interface.

The S63 AMG includes those items, but adds 20-inch AMG wheels and specific styling cues, as well as AMG-tuned suspension, steering, brakes and exhaust. Inside you get a sport steering wheel, shift paddles, an enhanced instrument cluster and AMG-specific leather and trim. Also included is Active Body Control, a suspension technology that reduces body roll in the corners. The available AMG Performance package increases its engine output and top speed.

Optional on the S350, S400 and S550, and standard on the S63 is the Premium 2 package that includes a rearview camera, front and rear parking sensors, keyless ignition/entry and front seats with massage, adjustable/active bolsters and enhanced headrests. The following optional packages are available on the S63 as well. The Driver Assistance package adds adaptive cruise control as well as blind-spot and lane-departure warning systems that take evasive action in the event of driver inaction (though not in the S400).

The Rear Seat package adds four-zone automatic climate control and eight-way power rear seats with memory, heating and ventilation. The Rear Seat Entertainment package includes a dual-screen rear seat entertainment system and two rear seat remotes that can control all functions in the COMAND system. Also optional are power-operated shades for the rear side windows, a panoramic sunroof, a heated steering wheel, a night-vision warning system and a 15-speaker Bang & Olufsen sound system.

The S600 and S65 AMG get all of the above optional features standard. The S600 also has 19-inch wheels, enhanced brakes and Active Body Control. The S65 AMG receives the S63's extra performance enhancements.

Optional on every S-Class is Splitview, which allows the driver and passenger to look at different media on the center COMAND screen. It includes a COMAND remote control for the passenger.

Each 2012 Mercedes-Benz S-Class model comes with a different engine. The S400 Hybrid features a 3.5-liter V6 paired to a seven-speed automatic transmission, an electric motor and a lithium-ion battery. It is rear-wheel drive only. Total output is 295 horsepower and 284 lb-ft of torque. In Edmunds performance testing, the S400 accelerated from a standstill to 60 mph in 7.7 seconds. EPA-estimated fuel economy is 19 mpg city/25 mpg highway and 21 mpg combined.

The S350 Bluetec features a 3.0-liter V6 turbodiesel that produces 240 hp and 455 lb-ft of torque. A seven-speed automatic and all-wheel drive (4Matic) are standard. In Edmunds testing, it went from zero to 60 mph in 7.5 seconds. It returns an EPA-estimated 21 mpg city/31 mpg highway and 25 mpg combined.

The S550 gets a twin-turbo 4.7-liter V8 that produces 429 hp and 516 lb-ft of torque. A seven-speed automatic and rear-wheel drive are standard, but all-wheel drive is optional. Mercedes estimates it will go from zero to 60 in 5.4 seconds, while returning 15/25/19 with rear-wheel drive and 15/24/18 with AWD.

The S600 gets a twin-turbo 5.5-liter V12 good for 510 hp and 612 lb-ft of torque. A five-speed automatic (required for the engine's extra torque) and rear-wheel drive are standard. Mercedes estimates it will go from zero to 60 in 4.5 seconds, while returning EPA-estimated fuel economy of 12/19/14.

The S63 AMG features a twin-turbo 5.5-liter V8 rated at 536 hp and 590 lb-ft of torque. With the AMG Performance package, it's upgraded to 563 and 664, respectively. Rear-wheel drive and a seven-speed automated manual transmission are standard. In Edmunds performance testing, a standard S63 hit 60 mph in 4.3 seconds. EPA-estimated fuel economy is 15/22/17.

Finally, the S65 AMG has a twin-turbo 6.0-liter V12 that cranks out 621 hp and 738 lb-ft of torque. A five-speed automatic and rear-wheel drive are standard. Mercedes estimates it'll hit 60 mph in 4.2 seconds, which isn't much quicker than the S63, but that's because the rear tires can't possibly handle that much power in such a test. Believe us, the car feels a lot faster. EPA-estimated fuel economy is 12/19/14.

Every S-Class comes standard with antilock brakes, stability and traction control, side airbags both front and rear, side curtain airbags, active head restraints and Mercedes-Benz mbrace emergency telematics. Also standard is the Mercedes PreSafe system, which can sense an impending crash and automatically tighten the seatbelts and reposition the power seats for maximum airbag protection.

Optional features, depending on the trim, include a lane-departure and blind-spot warning system with automatic brake intervention, infrared Night Vision Assist and PreSafe braking, which uses the optional adaptive cruise control's radar system to sense an impending crash and automatically apply the brakes.

In Edmunds brake testing, an S400 came to a stop in a solid 121 feet. Both AMG models stopped in an excellent 111 feet, while the S350 split the distance with a 116. Expect the S550 and S600 to be similar to that.

The 2012 Mercedes-Benz S-Class provides a ride you'd expect from a top-tier luxury sedan. The compliant suspension ably cancels out road imperfections while also keeping body roll in check, and the cabin remains as quiet as a library even over rough pavement. It simultaneously gives you that stately luxury-car feel, without making you feel overly isolated from driving.

However, how an S-Class drives is incredibly dependent on which engine is chosen. The S400 Hybrid is slower and has a less natural-feeling brake pedal, but otherwise it drives just like you'd expect from a Mercedes-Benz. The new S350 Bluetec feels mighty powerful around town thanks to its diesel engine, while getting the best fuel economy and range of any S-Class (and, in fact, any other full-size luxury car). You'll also be hard-pressed to tell it's a diesel, as the engine's louder-than-normal clatter is pretty much imperceptible from inside the cabin.

Stepping up to the S550 will likely deliver all the power anyone could ever need. The new twin-turbo V8 offers ample thrust while returning better fuel economy than before. The S600 turns the performance dial up even further, while the AMG models boast the handling and acceleration capabilities of much smaller sport sedans. There's never any hiding the immense size of the S-Class, but few cars can deliver this much performance and luxury in one package.

The Mercedes-Benz S-Class has been the standard-bearer for luxury for several decades and the latest incarnation upholds that tradition in grand style. With exquisite craftsmanship and attention to detail, the cabin features top-notch materials and exacting construction. If you want something richer, you'll have to step up to a Bentley or a Rolls-Royce.

The COMAND electronics system uses a control knob and screen to work most entertainment and navigation functions, but the lack of physical dash buttons (like those in the E-Class) tends to complicate the operation of frequently used functions. The S-Class' abundance of features can also be a bit overwhelming.

The S-Class is not available in a longer-wheelbase version as are some of its competitors, but we suspect few owners will desire more than what the Benz offers. Space is plentiful in any seat and added creature comforts like heated and ventilated seats with massage are sure to please even the toughest critics, whether they're seated front or back. The available Rear Seat Entertainment package even gives those in back full control over the COMAND system. The trunk can accommodate up to 16.2 cubic feet, which is a decent size for this class.