2022 Mercedes-Benz S350d W223

The straight-six diesel powered S350d is a supremely luxurious and impossibly comfortable entry point to the latest 223-series range, but in our fast-changing world its days could be numbered… Words Shane O’ Donoghue. Images Daimler AG.

The last hurrah? Base S350d turbodiesel is all the luxury saloon you ever need but could be the last of its kind

“Under the bonnet is the excellent OM656 diesel engine, a 2.9-litre in-line six-cylinder”

Conceivably, what we have here is the last new generation of S-Class saloon to be offered with a diesel engine. Mercedes itself already has a plug-in hybrid variant on the books (the S580e) that is expected to take a larger share of the sales than ever before. And that’s before we take the incredible new, all-electric EQS into consideration. This then, could be peak turbodiesel for Mercedes-Benz, a company that knows the technology better than any other.

Fittingly, prospective buyers don’t need to splash out on anything other than the entry level diesel engine to be impressed, as the S350d model is arguably all the car any self-respecting, long-distance-driving Mercedes owner needs. It is, in a word, sublime.

“Mercedes played it safe with the exterior design, but it completely reinvented the interior”

Under the bonnet is the latest iteration of the excellent OM656 diesel engine, a 2.9-litre in-line six-cylinder. The full 282bhp arrives at 3,400rpm and maximum torque of 442lb ft is available from just 1,200rpm. Officially, the 0-62mph time is 6.4 seconds, which is fast enough by any measure, but of more note is how smoothly the S350d gathers speed when it is already travelling along at a decent lick. Its performance isn’t ever startling, but that’s partly down to how the car isolates its occupants from the outside world.

Somewhat surprisingly, as lovely an engine as this is, and as melodic as it is for a diesel, it’s seemingly always audible. We’d stop short of calling it intrusively noisy, but even at a cruise there’s a distant rumble from under the bonnet, something that isn’t present in the petrol or hybrid versions of the S-Class.

The 9G-tronic automatic gearbox is an absolute gem, however. No matter which driving mode we used or how quickly or slowly we drove the car, we couldn’t catch it out. In many automatic diesel cars, when you push the accelerator down hard, but not to the kickdown switch, the gearbox still changes down a couple of gears, unnecessarily given the torque-rich nature of a turbodiesel – the S350d’s transmission avoids doing that, instead using the engine’s mountain of torque to push the car up to speed. It’s very satisfying.

Of course, the transmission strategy is probably also designed around economy. The official fuel economy figure is 40.4mpg and, while we struggled to get near that ambling around town and over more interesting country roads, we bettered the figure on a three-hour motorway run with the active cruise control set to the national speed limit and the car in its Comfort setting. That equates to not far off 700 miles on a single tank of diesel.

Smoothly does it

It’s a brilliant motorway car too, so stable and quiet and refined and capable that it’s quite obvious that it was designed to cope with much higher sustained speeds than we are allowed on Britain’s motorway network. For a quarter of our journey, the rain was coming down hard and traffic was heavy, yet the active cruise control coped without a hitch and there wasn’t a hint of instability over standing water. The smooth way the car adjusts its speed depending on traffic ahead aids relaxation, while the gentle steering assistance takes further load off the driver, making long trips a joy rather than a potential chore.

For a car that’s going to be used by chauffeur services, it shouldn’t be surprising that the S-Class is so good on the motorway, but how it performs away from such conditions may astonish the uninitiated. It is a wide car, but that’s about its only limiting factor on a twisty B-road, as it genuinely shrinks around the driver and reveals quite an engaging chassis under the veneer of luxury car sensibility. The steering is well weighted and even offers up something resembling feedback, even if the tyres’ progress on the surface below is muted on almost all surfaces.

The chassis balance is excellent, allowing this big car to nonchalantly carry its speed through a corner and even change direction more quickly than you’d expect possible. Through all this, the air suspension and adaptive damping work together to keep the body flat and the tyres in contact with the road, without ruffling the feathers of the passengers on board. Driven beyond how we’d expect most to, the car does eventually run out of wheel travel on a bumpy road, but even then, it soaks up the punishment and maintains its composure and pace. Yes, we are still talking about a car many will describe as a limousine. The previous-generation S-Class, the W222, also performed this trick, but the new one is even better at balancing comfort and control.

The place to be

The W223 S-Class is a conservative design, echoing the style of the rest of the Mercedes range, but elegant with it. The high-tech lighting and front bumper design give the low-set nose presence, but in general it slips by under the radar, with few realising they are looking at a range-topping model.

Until they glimpse the interior, that is. Mercedes played it safe with the exterior design, but it completely reinvented the interior. Gone is the upright ‘widescreen’ dashboard of the W222 and in its place a minimised design, with even more impressive technology at work. In front of the driver is a relatively modest screen for the instrumentation with several different layouts to choose from.

The tilted touchscreen in the middle draws your attention, though. When the car is switched off, it seamlessly combines with the shiny black front section of the centre console. Press the (rather oversized) engine start button, however, and it instantly comes to life, with crystal clear graphics, an easy menu system and, though the climate control switchgear has been moved to the screen, it is permanently visible at its base, so it’s quick and easy to use. Other switchgear around the cabin is touch-sensitive too, including the subtle fan speed adjustment buttons found on the stylised air vents. The central four rectangular vents under the windscreen look great too, but they could feel more solid. Likewise, the adjustment switchgear for the seats. It’s mounted on the doors, as before, but it isn’t designed to physically move. Meanwhile, the latest generation steering wheel looks great and the switchgear is of high quality, but the response to the touch-sensitive sliders is inconsistent and difficult to get right when you’re on the move.

Even with those few niggles, the cabin is a masterpiece. There’s even a ‘kinetics’ function that will, from time-to-time, adjust sections of the seat to ease long-distance driving aches and pains. The S-Class will even automatically set the seat position for you if you input your height. Those in the rear of the regular wheelbase model don’t get seat adjustment, but they do get plenty of space and their own climate control settings. Naturally, the cabin can be upgraded to prioritise back seat passengers, and a large proportion of S-Class customers opt for the Long-wheelbase model for that reason.

The S350d starts at £80,450 OTR in ‘base’ AMG Line form, while the AMG Line Premium model featured here (with optional 21-inch AMG alloys) is £87,145; add another £4,000 for ‘Long’ spec. The more expensive petrol and plug-in hybrid models may gain popularity this time around, but if you can’t or don’t want to plug in a car regularly, and you also don’t want to frequent refuelling stations, the S350d is undoubtedly the choice of the line up. We probably won’t get to say that again when the next generation of the S-Class comes around.

Just the facts 2022 Mercedes-Benz S350d (W223)

ENGINE OM656 2,925cc 6-cyl MAX POWER 282bhp @ 3,400-4,600rpm MAX TORQUE 442lb ft @ 1,200-3,200rpm TRANSMISSION 9-speed auto, RWDWEIGHT 2,020kg 0-62MPH 6.4sec TOP SPEED 155mph FUEL CONSUMPTION 40.4-42.8mpg CO2 EMISSIONS 184g/km YEARS PRODUCED 2020-2022

All figures from Mercedes-Benz for Standard-wheelbase car in AMG Line Premium spec; fuel consumption according to WLTP Combined

Luxury, electric rear seats offered with LWB spec.

This leather colour is called Sienna Brown. ­­ Rear MBUX touchscreen of Premium Plus.