New Car Reviews

2010 Mercedes Benz S400 Hybrid

Despite the fact that it debuted way back in 2005, the lovely Mercedes-Benz S-Class remains at the very top of its class. And the new hybrid model happens to add a (slightly) more responsible version. Pleasantly, the S400 Hybrid is also the least expensive S-class for sale today, with a base price of $88,825 versus the S550’s opening rate of $92,475. Sure, you might lose some cachet with the more traditional folks at your country club, but the overall fuel mileage gains of 3 mpg overall are pretty enticing. (The S400 is EPA rated at 19 mpg in the city, 26 mpg on the highway, and 21 mpg combined, which matches the EPA’s combined figure for the Lexus LS600hL. The S400’s trip computer indicated that I averaged 23 mpg over 320 weekend miles. The base-V-8-powered S-class, the S550, on the other hand, gets significantly lower ratings of 15 city/23 highway/18 combined mpg.)

Where the S400 falls short — not surprisingly given the two cylinders, 2.0 liters, and 107 hp deficit of its 3.5-liter V-6 as compared with the S550’s 5.5-liter V-8 — is in muscle. The electric component of the powertrain, which chips in with a 20-hp electric motor, definitely helps accelerative duties, but I found myself underwhelmed by the S400’s overall oomph on more than one occasion over the weekend. Owners of big German luxury cars (and I include the Lexus LS in that group) expect power on demand from their cars, and the S400 just barely delivers at times. Indeed, Mercedes says that the S400 takes 1.8 seconds longer (7.2 seconds total) than the S550 to reach 60 mph.

That’s not necessarily a deal-breaker, though. I think it’s admirable that Mercedes is providing buyers of its fantastic flagship with a more politically correct and affordable option.

Rusty Blackwell, Copy Editor

I didn’t find the S400 devoid of oomph like Rusty did, but it is easy to miss the sonorous wail and waves of torque produced by the S550’s 5.5-liter V-8.

I wish Mercedes-Benz had gone the full-hybrid route with this car, much like Lexus and did with their LS600h L. The Mercedes system may be less expensive to purchase, but the electric motor serves only to help counter the V-6’s power deficit during hard acceleration. Fuel economy gains seen in bumper-to-bumper traffic are largely due to the start/stop system, which shuts the six-cylinder down once the vehicle rolls to a stop.

Perhaps the most impressive aspect of this car is the fact that, apart from the silence at stop lights, it drives like virtually every other S-class — which is to say impeccably. For those who demand the utmost in luxury but would like to save a few gallons while slogging through midtown traffic, this is an interesting option.

Evan McCausland, Web Producer

I’m more with Evan on this one than with Rusty, although I only spent a short amount of time with the S400 Hybrid, whereas Rusty drove it more than 300 miles. But I suspect that, for a lot of S-class buyers, the S400 Hybrid will offer more than enough performance, because it retains all of the poise, polish, prestige, safety, and comfort of the conventional V-8-powered S-class, and it’s for those reasons more than any others that people buy the S-class, not for neck-snapping, off-the-line acceleration.

Joe DeMatio, Deputy Editor

What I miss in this hybrid isn’t so much the usual S-class power as the S-class smoothness. Oh, this is still one well-coordinated car, don’t get me wrong, but the tell tale brake sponginess and slightly less effortless buildup of power take a bit away from the car’s usual ability to completely isolate a driver from the nuisances of the outside world.

Still, this is small sacrifice of élan is hardly debilitating to the overall über-Mercedes experience. The car still provides all the comfort one expects of any vehicle in this segment, and, in my opinion, exceeds most of its rivals in terms of its sheer presence. The thoroughly decent efficiency doesn’t hurt either.

I remain unconvinced that luxury buyers care about saving fuel – especially when nothing about their purchase screams environmental friendliness – but clearly Mercedes and other automakers believe otherwise. More to the point, there’s really not a compelling reason for someone who isn’t an enthusiast to avoid this green version.

David Zenlea, Assistant Editor

Give this ‘Benz one green star for its blend of decent performance, exemplary fuel efficiency, and low emissions. Thanks to a 20-hp electric motor aiding the 275-hp 3.5-liter V-6, the S400 ties with the SLK300 in achieving 21 mpg (EPA combined), the best mileage of any gas-burning vehicle in the Mercedes lineup. The gas-electric blend is nicely subdued, the engine stop-start system is unobtrusive. Unfortunately, premium fuel is required.

The highest level of driving entertainment available in this eco-chic sedan is delivered in your driveway when you rummage through the toy box of personalization options. If only they were as well orchestrated as the hybrid driveline. To enjoy the seat-massage function, you must activate it every time the ignition switch is cycled. The trio of rear seat headrests can be retracted at the touch of a button but erecting them requires manual effort. And for no good reason, the sound system’s primary volume control is shrouded from the driver’s view by the COMAND system’s mouse.

Don Sherman, Technical Editor

I, for one, think Mercedes-Benz went the right route with this hybrid system. It can’t move the car without the gasoline engine kicking on, but it doesn’t compromise the trunk room like a Lexus LS 600h L to house batteries (don’t forget the Lexus costs $20,000 more!) Is it worth giving up 38% of your trunk (16.4 cubic feet vs 10.1) to move on electric power alone? Probably not for cars in this class. If I’m in the market for a giant sedan, I’d like to bring along more than a duffle bag in the trunk. Let’s not forget the Lexus only manages 1 extra mpg in the city and is down by 4 mpg on the highway according to the EPA. Of course this isn’t an apples-to-apples comparison because the Lexus hybrid is supposed to produce the power of a V-12 engine instead of just saving fuel.

My colleagues doubt the level of interest the typical luxury vehicle buyer has in hybrid powertrains. Let me remind you all that the take-rate on Cadillac Escalade hybrids is a very respectable 20%. It isn’t entirely rational to buy a large luxury vehicle and then opt for a hybrid powertrain, but that the whole idea of a luxury vehicle isn’t rational. There are some people who need to justify the purchase of a luxurious car and the hybrid option is largely a feel good justification for someone who really wants an S-class.

The real elephant in the room is diesel engines. How much would it have cost to certify a Bluetec S-class for the U.S. and what sort of fuel economy numbers would that car return? Given the hybrid’s 26 mpg highway rating, I don’t think it’s unreasonable to assume Mercedes could offer a diesel S-class that hits the magical 30 mpg mark on the highway cycle. Since cars like the S-class are best experienced on long highway drives anyway, that is much more intriguing to me than a hybrid system. But the American public still isn’t sold on diesels and everyone knows what a hybrid means, even if few people understand the wide range of hybrid systems available right now.

I’m just happy Mercedes is working on solutions that increase the fuel economy of big luxurious cruisers so these limos can still be sold after the increasingly difficult fuel economy regulations go into effect. As long as buyers don’t have to skimp on luxury touches to go green, it doesn’t really matter if diesels or hybrids ultimately win the fuel economy war.

Phil Floraday, Senior Online Editor

Cynics scoff at the hybridization of large SUVs or powerful luxury sedans, yet there are significant benefits even for seemingly marginal fuel economy gains in these vehicles. The S400 Hybrid, for example, has a combined rating of 21 mpg compared to the 18-mpg rating of the S550. That small 3-mpg increase doesn’t seem like much, but it is. Over 15,000 miles of driving, the hybrid would save you 119 gallons of fuel. To save that same amount of gas in 15,000 miles, a Honda Fit with an automatic transmission would require a 10-mpg increase in combined fuel economy, from 31 mpg to 41 mpg.

If our goal is to simply reduce fuel consumption, hybridization of the fleet is a pretty good solution, assuming S-class buyers aren’t going to purchase a Toyota Yaris anytime soon. Even small-scale systems can have a substantial impact on oil use. Furthermore, the S400 Hybrid proves there aren’t any significant drawbacks in switching from S550 to the gas-electric car. The comfort, technology, and big-luxury prestige are all intact. Rumor has it that the next S-class will feature a powertrain lineup that is exclusively hybrid. If that comes true, it’s a strong statement about the role that hybrids will play in the entire automotive fleet over the next ten years.

Eric Tingwall, Associate Editor

2010 Mercedes-Benz S400 Hybrid

Base price (with destination): $88,825
Price as tested: $94,570

Standard Equipment:
7-speed driver-adaptive automatic transmission
Direct-steer power-assisted speed-sensitive steering
Airmatic air suspension with adaptive damping
Cross-drilled front and rear brake rotors
Comand infotainment system with 40GB hard drive
GPS navigation
Bluetooth connectivity
15-speaker Harman/Kardon Logic7 surround sound
HD radio/in-dash 6-disc DVD/CD changer
Sirius satellite radio
8-inch Comand display
Power tilt/sliding sunroof
Power rear window sun shade
Bi-Xenon headlamps
Electric trunk closer
Full leather interior
Heated front seats
Dual-zone automatic climate control
Active head restraints
Electronic stability control

Options on this vehicle:
Premium 2 package — $4950
– Bi-Xenon headlamps with active curve illumination
– LED daytime running lights
– Heated and ventilated front seats
– Drive-dynamic multicontour front seats with massage
– Rearview camera

Diamond white paint — $795

Key options not on vehicle:
Rear seat entertainment package — $2450
Rear seat package — $2990
Driver assistance package — $2900
Sport package — $5800

Fuel economy:
19 / 26 / 21 mpg

Size: 3.5L V-6/electric hybrid
Horsepower: 295 hp @ 6000 rpm
Torque: 284 lb-ft @ 2400-5000 rpm


7-speed automatic with sport/comfort shift modes

Curb weight: 4474 lb

18 x 8.5-inch aluminum wheels
255/45R18 Continental ContiWinterContact ts810s winter tires

Competitors: Lexus LS600h, BMW ActiveHybrid 7

Buying Guide
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0-60 MPH:



19 City / 26 Hwy

Horse Power:

295 @ 6000