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Is the C-Class still a mini S-Class?

The W206-generation Mercedes C-Class is a transitional car for one of the world’s founding car makers, and yet it remains singularly important. It is the the first C-Class not to offer multi-cylinder combustion engines, for example, but also one of the last new Mercedes models of any series not to be engineered for all-electric power.

Needless to say, that doesn’t mean it won’t be ‘electrified’. In fact, Mercedes is aiming to attract particular attention, and win some key European fleet business, with plug-in hybrid models. Rest assured, there are still traditional non-hybridised petrol and diesel models to choose from, as well as hot AMG versions.

The C-Class, not being an SUV, might feel a bit old-school to some people. But there are plenty of other mid-sized executive saloons vying for your money. Some consider the BMW 3 Series as the de facto car in this segment, the Audi A4 has been on sale for an age but still feels wonderfully well made and the Jaguar XE offers something a bit more British feeling for those not after a car that's quite so Germanic. 

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DESIGN & STYLING

2 Mercedes C class C300e RT 2022 panning

This fifth-generation C-Class adopts Mercedes’ updated Modular Rear II model architecture. That’s a fact its maker is keen to communicate, because it has always talked up the effect of technology migrating from its flagship limousine down to its biggest-selling saloon. Mercedes followers will know, however, that the last S-Class (2014-2020) and C-Class (2014-2021) also shared their underpinnings.

The W206 is a little larger than previous generations and sticks with a traditional executive car mechanical layout of a longways-mounted engine up front, from where drive is taken to either the rear axle exclusively, or to both. The combustion engines are all four-cylinder units, now with 48V mild-hybrid assistance.

A 1.5-litre turbocharged petrol powers both the entry-level 168bhp C180 (which isn’t part of the UK model range) and the 201bhp C200, while primary power for both the 255bhp C300 and the 308bhp (petrol-electric combined) C300e comes from a 2.0-litre turbocharged four. The 197bhp C220d and 261bhp C300d diesels, meanwhile, are powered by a revised version of Mercedes’ OM654 engine with a new crankshaft and integrated starter-generator motor.

All C-Classes use a nine-speed automatic transmission, and the C300e PHEV adds a 127bhp permanently excited electric motor into its mechanical mix that can power the car all by itself at speeds of up to 87mph. It draws charge from a lithium ion drive battery that is smaller than the equivalent component in the outgoing C300e but also has nearly twice as much energy capacity: 25.4kWh in total.

That battery pack is now slim enough to leave the C300e with a flat, rather than stepped, boot floor. But it must be heavy. Our test car couldn’t be weighed on the day of our performance figures, but Mercedes’ own unladen running-order weight is 2005kg, making it 235kg heavier than a BMW 330e and 166kg heavier than an equivalent DS 9 PHEV (neither of which offers even half as much battery capacity).

For suspension and steering, the C300e differs slightly from other mid-range C-Classes. It is available only from Mercedes’ AMG Line model tier up but does without the lowered sport suspension of other AMG Line derivatives, and instead of sticking with coil springs at both ends, it uses self-levelling air suspension at the rear for closer body control of one of the car’s major masses.

The progressively geared power steering set-up of other AMG Line cars (which can now be combined with four-wheel steering, but only on the forthcoming Mercedes C43 and Mercedes C63 models) is also dispensed with for the C300e; and, irrespective of trim level, it rides on mixed-width 18in alloy wheels of an aerodynamic spoke design, as well as efficiency-minded Michelin Primacy 4 tyres.

INTERIOR

8 Mercedes C class C300e RT 2022 dashboard

It’s rare to find a press demonstrator from a premium car brand as modestly equipped as our test car. This represented the Mercedes C-Class at its simplest and cheapest (as far as UK sales go, at least). The test car's only fitted option was metallic paint.

And so to sit in it and still feel like you were in quite a lavishly designed and appointed environment, with all the equipment you would really need included as standard, came as a welcome initial affirmation of the car’s integrity as a luxury product.

The C-Class doesn’t stand up to close scrutiny of its on-board comfort and quality levels with quite as much distinction, though it certainly passes muster. You settle into a driver’s seat with plenty of room around it, in front of controls that are adjustable and well placed.

The sports seats aren’t especially comfortable or supportive, though (despite offering extendable cushions), while the margins of the driver’s footwell feel strangely restrictive around your toes and are marked by disappointingly flimsy plastics.

Most of the cabin’s fittings have a higher-quality solidity of feel, but there are dull and plain mouldings and sharper edges elsewhere too. Evidence of the odd cut cost, perhaps, that a Mercedes shouldn’t really betray.

The control layout is digitally replete. A 12.3in digital instrument screen immediately ahead of you is quite complex and busy with information at first but usefully versatile in the way it can be configured with practice. Dominating the centre console is a steeply raked 11.9in, portrait-oriented infotainment touchscreen whose bottom section permanently conveys the heating and ventilation controls.

The car’s rear passenger quarters are only averagely spacious for the segment: roomy enough for most adults and growing kids, and fairly comfortable, but not so for the tallest.

In the boot, you find a cargo space that’s usefully wide and it can be extended for length via folding rear seatbacks – but because of that battery placement, it still isn’t very deep. A minimum loading height of just 310mm (at the through-loading threshold) might not admit some bulkier everyday loads (although there’s always the estate bodystyle if day-to-day carrying is expected).

Multimedia system

Mercedes’ 11.9in MBUX touchscreen infotainment system for the C-Class is a version of the multimedia set-up first seen on the new Mercedes S-Class. It’s packed with all the right features, although several testers remarked that it wasn’t as intuitive to use as they had expected and didn’t like the way its raked screen angle made smudgy finger marks more obvious during daylight hours.

There is no separate haptic input device, and using the system while occasionally glancing away from the road is made harder by all the necessary menu swiping and scrolling. The alternative is to use the car’s steering-wheel thumb consoles to move a cursor around, which works fairly well, but it’s still too easy to brush these touch-sensitive pads inadvertently as you pass your hands around the wheel.

Mercedes’ natural speech recognition is supposed to make usability easier and, in some cases, does so quite well, but there are certain quick-fire functions that deserve a top-level button or shortcut on the screen and don’t get one. Wireless smartphone mirroring and device charging are included for no extra cost. 

ENGINES & PERFORMANCE

16 Mercedes C class C300e RT 2022 engine

Performance ranges wildly in the C-Class, as you'd expect from a car with so many different powertrains. Most models are around two tonnes, but they shoulder their mass effortlessly when they getting going.

On a cold, damp, slippery day at the proving ground, the C300e had enough traction and drivability to hit 60mph from rest in less than 6.0sec, and it needed little persuasion to do so besides a slightly feathered throttle on step-off.

In perfect test conditions, a 5.5sec time ought to be achievable, making this car a good half-second quicker off the mark than most of its rivals.

For outright in-gear potency in roll-on acceleration, the C300e’s performance feels comparable with that of a saloon with a multi-cylinder diesel motor – except that the electric motor’s ‘torque fill’ comes instantly, making for even better responsiveness than even that comparison would imply, as well as better mechanical refinement.

So when Mercedes argues that this car no longer needs six-cylinder engines, in one sense it is absolutely correct. Accelerating from 30-70mph in fourth gear takes just 6.5sec: the BMW 330d Touring we tested in 2020 was only seven-tenths quicker.

The regular C300, with 255bhp on tap, feels reasonably quick off the mark but a bit breathless further up the rev range. Overtaking at low speeds is effortless but you'll never feel the need to really manually hold onto the gears.

Diesel may be going out of fashion, but the two units make mincemeat of the car's heft. The C300d, with 261bhp and 406 lb ft, is plenty brisk and works seamlessly with the nine-speed auto box and mild-hybrid system. The C220d, meanwhile, is less powerful and refined but ultimately nearly quite as good as the C300d while being usefully cheaper.

RIDE & HANDLING

17 Mercedes C class C300e RT 2022 rear corner

The C-Class isn’t quite a natural sports saloon and it won’t be a default choice for interested drivers, but it handles well and, in slippery and testing conditions, it showed close enough body control and sufficiently well-balanced grip levels to carry plenty of speed, to maintain an interested driving style and to contain any kerb-weight-related negative impacts.

The car changes direction progressively rather than keenly and hints at handling adjustability in tighter bends without fully following through with much rear-driven handling flair.

But it generates more than enough grip, handling precision and dynamic composure to cover ground quickly when called on to do so, and is easy to drive briskly – which is probably exactly the effect its maker intended.

The chassis tune feels slightly comfort-biased at all times, with plenty of suppleness, but it stops well short of floating or wallowing on cross-country roads, and maintains good pitch control. Some body roll presents when cornering hard, but not enough to affect the steady-state grip levels, or to make the stability control electronics intervene intrusively. At the limit of grip, the front axle washes wide first, but with the weight of the batteries over the rear one, that’s probably as you would want it.

Vertical body control at speed over uneven roads is good – absorptive but hard to fluster. The steering is quite light and feels filtered, and it lacks a little in helpful definition of feedback, just like the brake pedal tuning.

Comfort and isolation

Generally the C-Class is well mannered car at cruise. In comparable test conditions, it recorded better results at both 30mph and 50mph than the DS 9 E-Tense PHEV (itself a subjectively pleasingly refined car) with its engine shut down and both wind and road noise quite well contained.

When the engine is running, especially when turning at revs, the story is a little different. At maximum engine revs in fourth gear, the car actually proved two decibels noisier than the DS 9, and noisier too when stationary and with the engine turning over at idle. The hush of the ride can be upset by certain coarser asphalt surfaces, which find a way through to reverberate a little in the cabin. By and large, though, the car is much more often quiet and relaxing than at all uncouth.

The visibility granted from the driver’s seat is good – about typical for a fairly compact saloon with chunky modern pillars, some of which are necessarily close to your eyeline. The primary-control ergonomics are sound, seating you low enough at the controls to feel nicely ensconced but high enough to give a good vantage point. A BMW 3 Series feels much more naturally sporting to sit in, but the C-Class marries convenience and comfort with an ideally positioned hip point well.

The driver’s seat itself could be more comfortably cushioned and effectively bolstered, though. Only one seat design is offered in UK-market C-Classes, with either electric (with memory function) or manual adjustment depending on trim level. There is no optional ‘comfort seat’. As they are, the seats offer lateral support that is ultimately less effective than they look fit for, and both shoulder and thigh support could also be improved.

Assisted driving notes

19 Mercedes c class c300e rt 2022 assisted driving

Mercedes uses its advanced suite of active safety systems as a lever to sell its highest-trim-level cars. So if you want a collision avoidance system with pedestrian and cyclist detection, or an adaptive cruise control system that can automatically adapt your speed to the posted limit, or a blindspot monitoring system clever enough to warn you before you open your driver’s door into the path of a passing motorbike? Well, you need to have AMG Line Premium Plus specification, and then add the Driving Assistance Package Plus on top, making for a rather expensive car.

As standard, Mercs get simpler blindspot warning, autonomous emergency braking and active lane keeping systems that all work fairly unobtrusively and effectively. The lane keeping system reactivates itself with every ignition cycle and can only be deactivated through the touchscreen, but there is at least a shortcut to switch it off.

MPG & RUNNING COSTS

Mercedes C-Class review

The C300e’s official electric range figure is 68 miles: close enough to the magic 70-mile threshold (which would have made it about the only 5% benefit-in-kind PHEV executive saloon of its type) to make a fleet driver roll their eyes in exasperation.

Our testing suggests that, in real-world use, you might only see better than 50 miles from a charge if you stick to slower intra-urban driving; and a range in the high 40s is more likely at greater speeds. Even so, that’s still strong enough to be a big relative motivator in a class in which only 25 miles of actual electric range is still probably the norm.

For longer-range drivers, or those who can’t charge often, extended-range fuel economy, as verified on our 70mph touring economy test, is a very creditable 49mpg.

Diesels still make a great case if you are a longer-range driver. We've seen around 60mpg from the C220d in real-world motorway testing and you can expect similarly as impressive figures from the C300d.

The C300 will be the least economical to run. Even so, we acheived close to 40mpg with our time in the car, mostly below motorway speeds.

VERDICT

20 Mercedes C class C300e RT 2022 Static

The Mercedes C-Class is a car that does most things very well, while bathing you in technology and comfort. The plug-in hybrid system offers more performance, better refinement and better extended-range economy and, crucially, much more electric range – with all the running-cost advantages and wider freedoms that brings.

It's also seriously refined on the motorway and will look great at your business meeting, or golf club. Mercedes has clearly thought about its target audience and really nailed what they expect.

However, we prefer the BMW 3 Series, even in plug-in hybrid form. The C-Class doesn’t have the driver appeal or material cabin quality of its opposite number from Munich.

Murray Scullion

Murray Scullion
Title: Digital editor

Murray has been a journalist for more than a decade. During that time he’s written for magazines, newspapers and websites, but he now finds himself as Autocar’s digital editor.

He leads the output of the website and contributes to all other digital aspects, including the social media channels, podcasts and videos. During his time he has reviewed cars ranging from £50 - £500,000, including Austin Allegros and Ferrari 812 Superfasts. He has also interviewed F1 megastars, knows his PCPs from his HPs and has written, researched and experimented with behavioural surplus and driverless technology.

Murray graduated from the University of Derby with a BA in Journalism in 2014 and has previously written for Classic Car Weekly, Modern Classics Magazine, buyacar.co.uk, parkers.co.uk and CAR Magazine, as well as carmagazine.co.uk.

Mercedes-Benz C-Class First drives