Mercedes-Benz SLK (2011 - 2015) used car review

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The third generation Mercedes SLK is an everyday-usable sports roadster that, like its arch-rival BMW's Z4, has a neat folding metal roof. Slick detailing, some incredible technology, low running costs and distinctive styling are all part of its appeal. Does this post-2011-era model make sense as a used buy? Let's find out.


MK2 version::2dr roadster, SLK 200K, 350, 250CDI, 55 AMG


The SLK was Mercedes' compact roadster model and sold between 1996 and 2015. Here, we're looking at the MK3 model version, but before we get to deeply into it, time for a re-cap. 'K' in Mercedes model language effectively stands for 'lite', essentially they say, a smaller, more compact but equally desirable version of the same thing. And sure enough, the SLK concept has always been based around delivering a more affordable, more accessible version of the brand's SL luxury convertible to the wider sportscar market.

At launch in first generation form back 1996, this car did just that, complete with an innovation of its own, a 'Vario' metal folding top that was quickly copied across the industry. Classed as a sportscar, it didn't drive like one. Instead, people bought it because they liked the badge and the clever roof. Which was fine until other premium brands got around to offering much the same thing with a more engaging roadgoing experience. Forced to up its game, the second generation SLK in 2004 was a big dynamic step forward, a trend the German brand claimed had continued with this third generation version, launched in mid-2011.

This car had quite a job on its hands, tasked with changing a whole buying demographic. SLKs up to his point had traditionally been bought mainly by undemanding, style-conscious older female buyers who wanted and could afford something nicer than metal folding roof cabrio versions of family hatchbacks like Peugeot's 308 or Renault's Megane. Keeping these customers while simultaneously appealing to the mostly male-orientated market that would usually opt for a sharper handling rival like an Audi TT Roadster, a BMW Z4 or a Porsche Boxster was never going to be easy. But Mercedes has never been a brand to shirk a challenge.

With this car, they aimed to keep the fashionistas loyal with an opulent, more spacious cabin and the option of a 'Magic Sky Control' roof that enabled drivers to switch from light to dark at the touch of a button as they cruised along the Kings Road. Enthusiasts meanwhile would, t was hoped, appreciate classic looks borrowed from the iconic 190SL of the Fifties, powerful engines and a clever optional Dynamic Handling Package provided to get the best from them. This SLK range sold until it was replaced by the SLC line-up in early 2016.

What You Get

Different, but somehow still the same is the aesthetic story with this third generation SLK. At launch, designer Michael Plessing rather candidly admitted that the previous version 'wasn't really a classic Mercedes'. Personally, we thought it rather neat, which if true was just as well for many of its long bonnet, short boot roadster proportions were retained by this MK3 model, despite the fact that this third generation version was over 30mm longer and wider, as well as being slightly taller. From the side, where chrome-finned ventilation grilles in the front wings are reminiscent of famous Mercedes-Benz roadsters of the Fifties, you might think this car to be little more than a facelift of its predecessor but from the front, the differences are obvious, clearly defined headlamps and an upright radiator grille creating a look that chimes with the car considered by many Merc enthusiasts as being the 'original' SLK - the legendary 190SL from the 1950s.

Styling preferences must always be slightly compromised in metal folding roof convertibles by the need to have somewhere to store all those weighty panels, but the SLK has less of an issue here than is the case with most of its contemporaries. Not that there are that many direct rivals from this era. Collapsible tin-tops have fallen from fashion in recent years, but with this car, Mercedes never considered reverting to the kind of fabric roof favoured by rivals like Audi's TT Roadster or Porsche's Boxster. Instead, they sought to make the folding metal roof trendy again by taking the 'metal' bit from the equation and giving customers the option to order their cars with a dark-tinted panoramic glass top. Or even go a step further and specify that glass panel with, wait for it, 'Magic Sky Control'. Ridiculous name, brilliant concept. Here, the glass roof panel pulses with electro-chromatic technology from the Maybach luxury limousine which at the push of a button, changes its molecular alignment to make the cabin either light or dark. If we were being cynical, we might suggest that you could achieve the same effect by installing a simple blind - but that wouldn't be as fun would it?

And after all, a car like this is all about how it makes you feel. Which is what we like most about the SLK. Yes, we're irritated that you can't operate the electrically folding Vario roof at speeds of over 2mph. But in every other way, this is a brilliantly thought-out cabrio. The roof opens or closes in just 20s and can be programmed to work from the keyfob so you don't need to disturb your cappuccino if you're sitting over the road from your car and the heavens open. More importantly for us, it has something that few other convertibles at any price can offer: decent roof-down cabin heating. Not only through the SLS-style 'jet turbine'-look air vents but also through the optional Airscarf neck-level heating system which sees warm air channelled up to the fascia vents and distributed liberally around your ears for feel-good freezing motoring.

Behind the multi-function flat-bottomed sports steering wheel, it feels a suitably premium place to be, everything around you feeling as if it's been built to last and the centre console and other trim parts gleaming with brushed aluminium. More traditional optional touches include an analogue clock and original buyers got the alternative of a wood finish. If you've come to this car from an older generation SLK, you'll immediately notice the extra shoulder room which makes the cabin feel significantly more spacious. There are no rear seats of course and precious little boot room either with the roof down - though to be fair, 225-litres isn't bad for this class of car. Both this figure and the 335-litre capacity you get when the roof is up significantly better those returned by this car's closest folding metal-topped roadster rival, BMW's Z4.

What You Pay

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What to Look For

Most buyers we surveyed seem to like their MK3 model SLKs. Where we did come across issues, it tended to be with the roof mechanism. The roof/boot space divider (which needs to be locked to lower the roof) can be very insecure and some customers reckon that the latches do not seat in the catch very well. For a few owners, this has caused the roof to jam both when open and closed. This then requires the bootlid to be manually opened prior to a physical wrestling with the divider in order to lock it into place so that the sensors can then allow the roof to work. In other words, fully test the mechanism several times before committing to purchase. If you encounter problems and the buyer responds with something along the lines of "They all do that sir....", then we'd suggest you walk away.

To be fair, the roof mechanism fitted to this MK3 variant is a lot more robust than that used on previous generation SLKs - and not much else goes wrong. Many will be tempted to give manual cars a wide berth but the good news is that the manual gearbox fitted to this MK3 SLK is a very good unit - a rarity for a Merc. This perception means that there's a relatively big premium for the automatic versions and keen drivers will be able to source competitively priced manuals if they're on the ball. The quality of the interiors is also a good deal better than it was on MK1 or MK2 SLKs. Check alloys for signs of kerbing and make sure the service stamps are up to date and that the alarm and immobiliser are functioning properly. Bear in mind too that the paintwork is very prone to stone chips.

Replacement Parts

(approx based on an SLK200 inc VAT) Brake pads are between £15-£32 for cheap brands or up to around £50 if you want an expensive make. Brake discs cost around £150 and brake callipers are around £235. A drive belt is around £25. Air filters are around £25. Oil filters cost around £10. A water pump is around £35 to £40. Spark plugs sit in the £11 to £16 bracket and you'll pay around £17 for a wiper blade. A timing chain would be about £40 and a cylinder head gasket about £25.

On the Road

A BMW Z4 or a Porsche Boxster is a direct, engaging driver's car, whether you want it to be or not. Having a wider customer base on its books, this SLK must be a little different and given Mercedes' need to satisfy that wider palette of interests, we think they did rather well with this MK3 model. Interior styling cues from the SLS AMG supercar get you in the right mood from the off and the engines on offer seem to have enough about them to promise reasonably brisk progress.

The whole SLK concept of 'less being more' was clearly demonstrated in the previous generation version of this car. That was a model you could bond with most closely not in rip-snorting AMG flagship form, but in simple four cylinder entry-level guise matched to a manual gearbox. You won't find many SLKs fitted with a manual gearbox - hardly any UK buyers wanted it - which seems a little curious given that we are talking about a sports roadster here. Still, the seven-speed 7G-Tronic Plus auto transmission does undoubtedly suit this car very well with its silky-smooth ratio changes and steering wheel-mounted paddles. Just as well really as unless you choose the entry-level SLK 200, it's the only option.

That variant has one of the two 1.8-litre four cylinder direct injection turbocharged petrol engines available in the range, units well familiar from the C-Class saloon that here offer 184bhp in SLK 200 form and a marginal increase to 204bhp if you go for an SLK 250. In both cases, you can expect pretty similar levels of performance, with rest to sixty achievable in around 7s on the way to a top speed of around 150mph, though to be fair, the difference between these two models is greater on the road than it looks on paper, thanks to the SLK 250 variant's greater low-down pulling power and rortier engine note. You'll have to sacrifice a little on the engine note front if you want the other four cylinder SLK alternative, the 204bhp 2.15-litre 250CDI diesel, but compensation comes with impressive frugality matched to performance near-identical to that of the four cylinder petrol models.

And if you're buying this car as a style-conscious statement, then that's about all you need to know when it comes to the Driving Experience. But for the more enthusiast-orientated audience that Mercedes hoped to attract with this third generation model, it'll be just the start. These people will want to find themselves an SLK fitted with uprated suspension: possibly the stiffer sports suspension option but ideally the Dynamic Handling package. Here, continuously adjustable damping automatically sets the car up to suit the surface you're on and the mood you're in. Enthusiasts will also want an SLK in which this system has been matched to a sharper Direct-Steer steering set-up, replacing the vagueness of the standard system. And Torque Vectoring brakes that add minute braking forces to the inside rear wheels through a corner to help the car turn in more sharply.

The result of all this cleverness isn't quite enough to turn this car into a Porsche Boxster but it's enough to get it surprising close. Especially if you opt for arguably our favourite model in this third generation line-up, the V6 3.5-litre petrol SLK 350. Seriously fast with 306bhp, it dispatches sixty from rest in just 5.6s and has to be artificially restrained at 155mph. So it's just a second slower than the SLK 55 AMG flagship model that's far thirstier but compensates with a glorious barrage of aural entertainment from its 422bhp 5.5-litre V8.

In summary? Well, you still wouldn't buy an SLK for trackday heroics. And you probably wouldn't buy one if all you wanted was a spot of backroad weekend fun. But as an everyday-usable roadster, it's very complete package indeed, leading the class from its era in ride quality, refinement and comfort. On paper, those don't sound like attributes that should be sportscar priorities, but in practice, they matter very much. Roof-down on a typical cold British day cruising fluidly along the bumpiest back road, we love the way the cabin cossets you from buffeting with its clever pivoting Airguide draught-stop that attaches to the anti-roll bars. And the way it warms you with its powerful heater and Airscarf neck vents. It's all enough to make you want to use a car like this that little bit more. Other rivals might be sharper. But they don't encourage you to go fast and al fresco quite as regularly. Which for us, is the SLK's real charm.


Back in 1996, the Mercedes SLK re-invented the coupe-cabriolet concept for the modern age. In this third generation guise, it continued to do just that. According to SLK wisdom, a roadster needn't be uncomfortable to drive in town or on long trips. It need cost no more than a family hatchback to run. It can make you feel at one with the elements even when the roof's up. And when you can go al fresco, the coldest day can feel as warm as it would be were the top to be closed. These are all attributes that rivals struggle to match, even if some of them might be cheaper or sharper to drive.

Here then is a car from a brand that perfectly understands its target audience. A car that in MK3 model form, became more finely attuned to its market than ever before. A car offering a level of engine efficiency and technology that makes many rivals from its era seem from a prior generation. If you believed that the two-seat roadster was becoming a selfish and irresponsible indulgence, Mercedes clearly thinks it can persuade you otherwise.

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