Efficiency-minded buyers have their pick of hybrid or diesel with the S-class. The turbo-diesel V-6 is projected to earn a rating of 20/31 mpg on the EPA fuel economy cycle and is both refined and authoritative, but it is slow to respond off the line and during downshifts. Accordingly, we're not as impressed with the new engine as we have been with the less powerful Mercedes diesel or the diesels offered by BMW and Audi. For now, though, Mercedes is the only company to offer a diesel in a flagship luxury sedan. The S400 Hybrid was the first gas/electric car to use lithium-ion batteries and delivers impressive fuel economy and smooth acceleration from its V-6 engine and electric motor, but at 19/25 mpg it isn't as efficient as the diesel. The rest of the lineup focuses on speed, not economy. The S550 is powered by a 4.7-liter twin-turbo V-8 and accelerates to 60 mph in 5.4 seconds. Next up the food chain is the 510-hp S600 supersedan with a twin-turbo V-12 engine that accomplishes the same task in a paltry 4.5 seconds. Then there's the 536-hp S63 AMG with the twin-turbocharged 5.5-liter V-8 that has replaced the 6.2-liter normally aspirated V-8. All those luxorockets, however, are left behind by the ludicrously fast S65 AMG and its twin-turbo V-12 that makes 621 hp and a massive 738 lb-ft of torque. But the S-class is more than great engines; it's also a driver's delight thanks to a balanced chassis, superb steering, and a supple ride.
Drive: Rear-wheel, 4-wheel
Trim levels: S350 BlueTec, S450 Hybrid, S550, S600, S63 AMG, S65 AMG
Body style: Sedan, 5-passenger
Engines: 3.0L turbo-diesel V-6, 240 hp, 455 lb-ft
3.5L V-6/electric hybrid, 275 hp, 258 lb-ft
4.7L twin-turbo V-8, 429 hp, 516 lb-ft
5.5L twin-turbo V-8, 536/563 hp, 590/664 lb-ft
5.5L twin-turbo V-12, 510 hp, 612 lb-ft
6.0L twin-turbo V-12, 621 hp, 738 lb-ft
Transmissions: 5- or 7-speed automatic
Passenger volume: 125.0 cu ft
Cargo space: 16.4 cu ft
The current S-class is nearing the end of its life cycle, but Mercedes has updated its flagship for 2012 with a new diesel model and a replacement engine for the S550. The diesel powerplant is a higher output version of the familiar 3.0-liter V-6 that produces 240 hp and 455 lb-ft of torque. S550 buyers now receive a smaller V-8 engine, but it has two turbochargers that allow it to top the old 5.5-liter in both fuel economy and power.
Standard features on the S-class include ABS; dual-stage front, front and rear side, and side curtain air bags; traction and stability control; tire-pressure monitoring; and driver-drowsiness alert. Buyers can choose from night vision with pedestrian detection, a rearview camera, blind-spot monitoring, lane-keep assist, parking sensors, and adaptive cruise control.
EPA Fuel Economy
All: 12-20 mpg city/19-31 mpg highway
- Diesel and hybrid options
- Supple ride
- Gorgeous interior
You Won't Like
- Not as agile as an A8 or a 7-series
- In need of a redesign
A car to be chauffeured in that you'll want to drive.
If You Like This Vehicle
- Audi A8
- BMW 7-series
- Jaguar XJ
- Lexus LS