2010 Mercedes-Benz S-Class S400 Hybrid Road Test

2010 Mercedes-Benz S-Class S400 Hybrid Road Test

  • Full Review
  • Pricing & Specs
  • Road Tests (3)
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2010 Mercedes-Benz S400 Hybrid

(3.5L V6 Hybrid 7-speed Automatic)


Regal passenger accommodations, high-tech features, superlative ride, good fuel economy for its class.


Strange brake pedal feel, plentiful electronic systems yield complicated controls.

The Mercedes-Benz Rube Goldberg Project

The Mercedes-Benz S-Class is a magnificent automobile. Everything looks, feels and sounds as if it were meticulously engineered to a degree that's a step above everything else. This is the car that introduced us to the antilock brake and the navigation system: an automotive trend-setter if there ever was one. The latest family member -- the 2010 Mercedes-Benz S400 Hybrid -- is no exception, but in a way, it's seems like a Rube Goldberg machine.

You know Rube Goldberg machines, those projects they make you do in physics class -- an overly complex solution to a simple goal. Think the game Mouse Trap. Instead of capturing a plastic rodent, though, the S400's goal is twofold: achieve better fuel economy and make a cheaper entry-level model.

To do the first, the S400 utilizes a mild hybrid system that consists of a 3.5-liter V6, a small electric motor and a lithium-ion battery. Automatic engine shut-off, regenerative braking and electrohydraulic power steering are also part of the package. A mild hybrid system is inherently cheaper than a Prius-like full hybrid system, so it's not that expensive to produce, and thus Mercedes actually charges $1,400 less for it than a comparably equipped S550.

So goal achieved, except Mercedes could have met the same goal simply by selling its non-hybrid V6-powered S350 model that it sells in Europe. Fuel economy and acceleration of the two S-Class models are roughly the same, while the S350's price would theoretically be even cheaper.

Ergo, the 2010 Mercedes-Benz S400 Hybrid is indeed an overly complex solution. However, there is a third goal: Sell something with a badge that says "Hybrid." There's a certain cachet in that, a cachet far greater than any base model S350 could ever have. Heck, there's a certain element that will look upon the S400 Hybrid as something greater than the range-topping S65 AMG. Taking that into consideration, the S400 Hybrid would seem to be a necessary Rube Goldberg project -- one that is nevertheless still a truly magnificent automobile.


The 2010 Mercedes-Benz S400 Hybrid is considered a mild hybrid. Unlike a Prius or Mercedes' own ML450 Hybrid, it cannot accelerate using electric power alone. Instead, a 20-horsepower electric motor receives power from a lithium-ion battery under the hood (the first of its kind in a hybrid) to provide a small amount of assist to the gasoline-powered 3.5-liter V6. More importantly, it keeps the car's electronics and air-conditioner working when that V6 shuts down when stopped to save fuel. Total output is 295 hp and 284 pound-feet of torque. The transmission is a typical seven-speed automatic -- no fancy two-mode systems or continuously variable transmissions at play.

The result at the drag strip is a 0-60 time of 7.7 seconds, a full 2 seconds slower than the last S550 we tested. We wouldn't call this S-Class slow, but it certainly doesn't have the cojones we've come to expect from the Mercedes flagship. Still, it does achieve 3 mpg better fuel economy than the S550, with an EPA-estimated 19 mpg city/26 mpg highway and 21 mpg combined. Incidentally, that's the same combined number as the substantially more expensive, full-hybrid Lexus LS 600h L. With a 23.8-gallon fuel tank, the S400's estimated highway range is more than 600 miles.

The S400 Hybrid's alterations to the S-Class formula don't end with the powertrain, however. Regenerative braking is utilized to recharge the battery, which lends the brake pedal a rather firm, abrupt feel that's atypical to the Mercedes norm. This, along with less grippy all-season tires, results in a stop of 121 feet from 60 mph, which is 13 feet longer than the last S550 we tested (it had performance tires).

It's typical for a hybrid model to tip the scales on the north side of porky relative its non-hybrid versions, but the 2010 Mercedes-Benz S400 bucks this trend thanks to the compact lithium-ion battery. Less weight means that the S400 remains fairly agile for a big limo, especially when you engage the Sport setting of the adjustable air suspension. Those all-season tires didn't do the S400 any favors in the slalom (62.3 mph) or on the skid pad (0.76g), but they produce a slightly quieter and more comfortable ride. Seems like a trade-off most S-Class buyers would be willing to make.


Our S400 Hybrid tester came with $24,000 of options -- most of which fell under the comfort category. The Rear Seat package was our favorite, including outboard seats that are heated, ventilated and eight-way adjustable. Four-zone climate control is also included, and the optional Rear-Seat Entertainment package gives each outboard passenger their own video screen and remote that not only controls their own screen, but the front cabin's COMAND electronics interface as well.

Up front, our tester came with the optional heated, cooled, active bolstering and massaging seats. It's already standard with 14-way adjustment, so needless to say, the S400's pretty darn comfortable. The massaging feature in particular can cure a sore back during a long trip.

In terms of wind and road noise, it doesn't get much better than a Mercedes-Benz S-Class. It was like Tut's tomb over Los Angeles' notoriously loud and gnarled freeway concrete. The ride is also exemplary whether in Comfort or Sport mode. The former can get a bit floaty at times and the latter offers a bit more impact harshness, but both are better sorted and provide more comfort than a majority of cars on the road.


The 2010 Mercedes-Benz S-Class is not the sort of car you just jump in and drive away. The shifter is an electronic stalk, the speedometer is a multifunction LCD screen and there are 3 million (give or take) electronic functions you can alter using the COMAND electronics interface, from a simple radio station change to the passenger side shoulder lumbar adjustment. It's complex and can be occasionally distracting, but you grow accustomed to it all once you clear the steep learning curve. As usual, there is a hybrid power system monitor on board, but as usual, it's as much a distraction as it is useful.

Most hybrid versions of regular cars usually suffer a loss in cargo capacity because of large battery packs stored in or around the trunk. Not so the S400, which keeps its battery under the hood. As such, the healthy 16.2-cubic-foot trunk is left untouched to provide more than enough room for multiple golf bags and a couple sizable suitcases. For buyers with children, the S400 is one of the few cars that can house a rear-facing child seat without requiring you to scoot up the front seats.

The S400's airy greenhouse provides good outward visibility, but it has a multitude of electronic aids when that isn't enough. We usually find that blind-spot warning systems are rendered redundant with properly placed mirrors, but the S-Class is so long and its mirrors not quite large enough that the optional warning system saved us a few embarrassing calls to the insurance company. We could do without the lane departure warning system and night-vision camera (the latter is better suited for those who frequently drive on rural roads), but the rearview parking camera and front parking sensors are bumper savers.

Design/Fit and Finish

You may look at the S400's $87,950 base price and ask, "Is it really worth $5,000 more than a BMW 750i or $17,000 more than a Lexus LS 460 L?" Well, feel all the surfaces, behold the classic unfettered design and operate each of the cabin's many knobs and switches. Quite simply, the S-Class is a notch ahead of everything else in its class (though the new Jag XJ is close). You pay more for the S-Class, but it feels like you should.

The exterior of our S400 Hybrid came with the $5,900 Sport package that includes AMG 19-inch wheels and special body styling that includes front and rear bumpers and side skirts. These look nice, but are definitely not worth nearly $6 grand given that the changes made to all S-Classes for 2010 -- LED running lights, slightly more modern front and rear fascias -- have made the car more attractive.

Who should consider this vehicle

Any luxury flagship sedan shopper who prioritizes fuel economy over power should check out the 2010 Mercedes-Benz S400 Hybrid. In fact, even if you're not prioritizing fuel economy, the S400 is still the cheapest way to get into one of the finest cars in the world.

Others To Consider
Audi A8, BMW 750Li, Jaguar XJ L, Lexus LS 460 L.

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