Road Test - Mercedes-Benz S350L BlueTEC SE Line

Mercedes-Benz spent most of 2013 hyping up the new S-Class, with a spectacular unveil in Hamburg and a jetlag-special 48-hour trip to Toronto for a first drive.

Now it’s here and on sale – and we can truly find out if it lives up to the hype. We tested this month’s cover star, a new S350L, just before Christmas. That was the week when the heavens opened and drowned much of Britain in torrential rain – which gave us the opportunity to push the car’s safety systems to their limits.

PD web road test merc S350L header

External styling

You’re immediately struck by how different the new car looks compared to the old model. The bigger, bolder grille gives real frontal presence, while the more streamlined boat-like tail makes the car look, if anything, smaller and neater from the front three-quarter angle. It’s an interesting effect – in fact the new S is dimensionally bigger in just about every way compared to the old car.

There is a moderate increase in all the interior dimensions: 12mm of extra headroom for the driver, as well as 14mm more shoulder room and 10mm more elbow room in the front. There’s a 14mm increase in rear knee room for passengers in the rear. Shoulder room in the rear has been improved by up to 9mm.

PD web road test merc S350L rear view

It’s also 100kg lighter than the old S-Class, and the new shape is more aerodynamic, with a drag coefficient of 0.24 on the S350, down from 0.26 on the current-shape S-class. One major weight saving is a switch to LED lighting. S-Class is the first vehicle in the world without a single conventional light bulb. Instead, almost 500 LEDs illuminate the road, the vehicle, the interior and the boot.

Interior trim

Our silver test car is as close as we could get to chauffeur spec – a subtle charcoal interior with muted, grey wood and aluminium details. And indeed, the plain, darker colour highlights the still-spectacular interior, with its large twin screens and subtle mood lighting around the dashboard screens and under the door cappings.

PD web road test merc S350L front seats

This looks as enchanting in the dark of the British winter as it did in the Stuttgart laboratory, where we first saw it. It really does put a smile on your face to switch on a sunny orange glow on a dark morning, or switch to a moody mauve in the evening.

The mood lighting makes the entire dashboard appear to float in its cowl. The dashboard has no analogue dials at all – it’s basically two 8:3 format TFT screens side by side, one carrying digital speedometer, rev counter and trip information, the other an impressively clear map, together with other selectable information, such as route guidance or fuel economy, as well as vehicle settings and infotainment. The various car settings – climate control, seats, lighting and so on, are accompanied by animated graphics of the S-Class.

PD web road test merc S350L digital dash

The central screen can also be switched to a 360-degree top-down parking view as well as a traditional rear-view, using cameras mounted in front, rear and door mirrors. The split-screen means all the views can be seen together. And an optional self-parking facility is also available, including a braking function. Low-speed impacts should be all but eliminated on this car.

Information technology

The night vision system fitted to the old S-Class carries over, but with substantial improvements. The camera now includes thermal imaging as well as infra-red, so people or animals are highlighted in red on the display, which now appears between the primary dials, and can be used at any time, not just in the dark. It’s so clever it can distinguish between people or large animals, and if a human is detected, the car will automatically flash its lights. It won’t flash for a horse or a deer, as this might cause the animal to freeze rather than run away.

The mood lighting colour palette is one of many vehicle functions can be changed via the Mercedes Comand system – a large dial and buttons positioned on the centre console. It’s similar to the system in the E-class and the old-style S, but with more buttons in fingertip reach of the dial, giving access to well-used functions such as, sat-nav, radio, phone and seats.

The COMAND input device now also has a touch-sensitive keypad under the padded wrist-rest. This is programmable – so for example a favourite phone number or sat-nav destination can be assigned a 0-9 number, giving one-touch access to frequently-accessed information.

PD web road test merc S350L parking

The centre screen is a twin-view screen, similar to that fitted in the Jaguar XJ, which allows the front seat passenger to view different information to the driver. So the passenger can watch a DVD while the driver follows the sat-nav. The infotainment system is backed by a huge 200 gigabyte hard drive – enough for a substantial music and movie library. 

Meanwhile passengers in the rear can view separate information on the rear headrest-mounted screens. Indeed, four different displays could be viewed – so rear passengers can watch TV or surf the internet while the front seat passenger watches a film. The car is a mobile wifi hotspot, with enough connectivity for every passenger’s phone, tablet and laptop. And a special Mercedes app can be downloaded allowing the car’s infotainment system to be controlled from the passenger’s own device.

Our car came with front and rear massage seats – an expensive option but one you’ll enjoy. The massage functions include a programme that heats the tips of the internal massage mechanism, simulating a hot-stone massage. When we first experienced this in the summer we guessed it would be extremely welcome in the depth of the British winter. We were absolutely right!

As well as the massage functions, the seats also have motorised side panels that hold you in place under cornering forces, and the multiple adjustments, controlled via clear buttons on the door, make it one of the most comfortable cars we’ve driven.

PD web road test merc S350L satnav

The screen displays may be hi-tech and futuristic, but the rest of the interior is classical luxury, with high-quality leather finishes, including quilted, perforated leather on the dashboard and super-soft headrest cushions on the rear seats. The lower half of the dash features a sweep of wood with four chrome air vents and an analogue clock – the only non-digital display in the car.

Performance and safety

The S350L powertrain carries over largely unchanged from the old car, with the 3-litre six-cylinder diesel and 7GTronic seven-speed auto box. CO2 emissions have been improved to 148g/km, down from 164g/km, and a lot of work has gone into reducing noise and vibration, including better aerodynamics below the car and extra sound-deadening materials both outside and inside the bodyshell. Air suspension is superb, though we knew that from the old-shape S.

Distronic Plus adaptive cruise control is fitted. This appears more responsive than before – when following a slower car, the acceleration response is much faster when it moves out of the way, or when you pull out to overtake. Deceleration is smoother too, while remaining firm.

Factor in a lane guidance system that pulls the car back into lane if it starts to wander, as well as warning the driver via dashboard graphics and vibrations through the steering wheel, and the S-Class almost drives itself. A “hands-free” graphic also pops up if you take both hands off the wheel, and the car remains in late.

One of the trade-offs with these systems is a switch to electro-mechanical power steering. Mercedes has fitted this system to both E-Class and S-Class, and it does make a subtle difference in the handling – though it’s not detrimental and if anything makes the car easier to manoeuvre at low speeds.

Give the appalling winter driving conditions we were able to push these safety systems to their limits. On an inundated M40 motorway, with rain and spray lashing the car, there simply came a point when Distronic’s cameras and sensors simply couldn’t cope – and the system shut down, with a clear visual and audible warning on the dashboard screen. 

It hadn’t stopped working – but had simply decided that the conditions were no longer safe enough for the driver to trust its judgement. In fact, as the rain and spray abated, Distronic Plus again informed me that it was working again, and it was safe to switch it on again. It’s very impressive – the fact that the system knows its limits should serve as a warning to the driver too – slow down and keep your distance when conditions are bad.

We didn’t experience snow, but we were glad of the fitted winter tyres on roads that were awash. That’s another reminder of the value of winter rubber – it’s not just about traction in snow and ice. Stopping safely in the wet is another vital function of winter tyres.

Rear seat and luggage space

Rear seat comfort, as you’d expect, is exceptional. The rear seating position is higher than the driver’s seat, so the forward view is good. And despite a seemingly lower roof line, the headroom doesn’t appear to be compromised.

PD web road test merc S350L rear seats

Rear seat options include a bench seat with fold down central armrest with cupholders and storage (as fitted to our test car), or two separate seats with a large central console, featuring airliner-style fold-out lap tables.

The nearside rear passenger has the option of extended legroom, by folding the front passenger seat forward to the maximum extent. This can be controlled simply by pushing a button on the rear door-mounted control panel, which gives the rear seat passenger control of the front seat.

The optional Executive seat back can then be reclined to an almost-prone 43.5 degrees, allowing your passenger to take an en-route nap. Even the standard seat versions have the foldable front seats, so taller passengers can really stretch out. When the rear seat folds forward, the seat-mounted rear screen adjusts its angle automatically so it can still be viewed.

The boot offers 510 litres of space, despite the hoop hinges, which are necessary for motorised opening and closing. The boot can be opened by kicking a foot under the rear of the car, which is handy if you're carrying cases in both hands.

PD web road test merc S350L boot


The S-Class undoubtedly delivers. It’s a leap forward for the class, even compared with excellent competitors such as the Audi A8L, Professional Driver’s Chauffeur Car of the year in 2013, and recently facelifted, as well as the also-recently-improved Jaguar XJL and BMW 730Ld.

Driving dynamics are better, though on our loaded test car you’re made aware of the automatic interventions such as Distronic Plus and Lane Departure correction systems. It feels super-safe, and we tested it in some dreadful weather conditions.

Fuel economy is decent, though perhaps less of a leap forward than the styling, features and in particular the interior. We achieved 33.6mpg overall on 378 miles of driving at an average 30mph – good, but well short of the quoted 50.4mpg combined. We also measured the fuel economy on a longer run at motorway speed – 232 miles at an average 63mph yielded an impressive 40.3mpg.

However, these returns are pretty much on the money for the sector – the S350L won’t give you a major advantage over key rivals. You’ll have to wait until the S300 BlueTEC Hybrid arrives later this year for a quantum leap in consumption and CO2 emissions.

The other downside right now is price. As usual, we tested a car with loaded spec – even without all the electronic driving aids, you’re looking at a £70,000 price tag for just the rear seat add-ons. And as demand is outstripping supply right now, you might struggle to find a new S-Class at a discounted price.

On the other hand, rival products can be sourced for around £50,000 – so if you’re in the market for a bargain buy, it might be best to avoid the S-Class until the new-launch hoopla has died down. On the other hand, if you want the hottest and most distinctive chauffeur car on the market, and the one with by far the best interior, you’ll have to bite the bullet. Advantage Mercedes-Benz...


Mercedes-Benz S350L BlueTEC SE Line

Price  £64,650 
Options fitted  
360° camera


Electric panoramic glass sunroof


Keyless-Go Comfort Package


Privacy glass


Air-Balance Package


Heated/cooled front seats


Executive Rear Package


Front double cup holder


Front Seat Comfort Package with massage


Front Seat Memory Package


Rear Seat Comfort Package


Rear Seat Reclining Package


Driving Assistance Package


Night View Assist Plus


Pre-Safe Rear Package


Six-disc changer


Telephone pre-wiring with hands-free facility


Black Poplar wood trim


Nappa leather upholstery


Total Price as tested


Engine 3.0-litre 24v common-rail turbodiesel V6
Transmission 7-speed &G-Tronic automatic, rear-wheel drive
Power 258bhp at 3,600rpm
Torque 620Nm at 1,600-2,400rpm
0-62mph 6.8sec
CO2 emissions 148g/km
Fuel consumption 50.4mpg (combined)
Luggage volume 510 litres
Wheelbase 3,165mm
Length 5,246 mm
Width 1,899mm
Height 1,496mm
Turning circle 12.3m
Fuel tank capacity 70 litres
Insurance Group 49
VED Band F
Warranty 3 years, unlimited mileage


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