Review and road test of the Mercedes-Benz SL [R231] (2012 - 2016)
BY JONATHAN CROUCH
Luxury sportscar buyers traditionally sold on the charms on a Mercedes SL will certainly be sold on this sixth generation version. They'll like the lithe proportions and deft detailing, the powerful engines and luxurious technology. But there's so much more to this revolutionary MK6 model than that. It was, in every respect, a landmark machine for its maker. As every SL should be.
MODELS COVERED: 2dr Coupe/Convertible (SL 350, SL 400, SL 500, SL 600, SL 63 AMG, SL 65 AMG, SL 65 AMG Black Series)
There aren't many truly iconic cars in the modern motor industry - but this is one of them: the Mercedes SL. The fundamental thinking behind standard setters of this sort doesn't tend to alter very much, but here it's different. Over six generations spanning as many decades, everything has changed about this car - yet in many ways, nothing is different. For Three-Pointed Star buyers, it's still the ultimate expression of sporting opulence and remains perhaps the definitive face of this legendary luxury brand. Yet one that over more than sixty years has changed from supercar to sports roadster and from there through boulevard cruiser to autobahn bruiser. A design, in other words, that through its lifetime, has managed at different times and in different forms to define everything a sportscar should be.
When first the SL appeared in 1952 to spearhead the brand's peacetime return to motorsport, the post-war German economic miracle had hardly begun and many Mercedes factories still lay in ruins. Undaunted, the company's head of testing Rudolph Uhlenhaut decreed that the marque would use this car to win the Le Mans 24 hour race - which it duly did, the perfect platform for the brand's subsequent successful return to Grand Prix grid. And that might have been the end of the SL story had it not been for an entrepreneurial Austrian-born US businessman called Max Hoffman. Recognising the sales potential for a car like the SL, he persuaded the Mercedes board to reinvent it as a different kind of sporting machine, more of a grand touring GT, still fast, but not as frantic.
And so were laid the foundations for the car we know today. The Gullwing version of the Fifties, the Pagoda model of the Sixties and the R107 series made famous by the Ewings on TV in 'Dallas' in the Seventies. Hi-tech arrived in 1989 with an R129 generation that pioneered pop-up rollbars and integral seatbelts. And more was served up in 2001 with an R230 series design whose folding metal Vario roof gave SL buyers both coupe and roadster rolled into one. A portfolio then, that has given us everything from affordable roadster to luxury sportscar and sensational supercar - and in so doing has laid the foundations for the Mercedes sportscar range we have today, beginning with the compact SLC and culminating with the extravagant AMG GT.
The SL we're considering here as a used car buy is the original version of the sixth generation SL, the 'R231'-series model that sold between 2012 and 2016. It was a design that, like the 1952 original, properly lived up to its name. 'SL', after all, stands for 'Sport Leicht' and this car, like that one, is made almost entirely from lightweight aluminium. It sold until a significantly facelifted version was launched in the Spring of 2016.
What You Get
Let's start with the fineries of fashion - classic SL proportions that have evolved through six generations and nearly half the history of this famous brand: the long bonnet, the compact passenger cell set well back within the wheelbase and a muscular, racy-looking tail. If you know anything at all about this car, you'd recognise one without the badgework, admiring, perhaps, the way that the grille has been positioned to visually lengthen the bonnet. The shoulder lines that rise from the headlamps and stretch like tensed muscles along the bodywork into the tail lights. Or the side grilles with fins in each front wing that visually reference the legendary Gullwing and form the starting point for feature lines which seem to give the car a forward thrust, even when it's standing still.
But it's what you can't see that's important here. 'SL' may stand for 'Sport Leicht' but historically, this model has always been something of a sporting heavy hitter, big in bulk and to compensate, well provided for in power. It was a combination hardly in keeping with these eco-conscious times and when early development suggested that despite the engineers' best efforts, this sixth generation model would be even lardier, the Stuttgart board took a deep breath and decided to turn the clock back. The very first SL in 1952 was made from aluminium: so too, would be this sixth generation version. That, they knew, would make it expensive for the Bremen factory to build. But weight savings for mainstream models of between 125 and 140kg would also make them a lot less costly for owners to run.
Of course, this car could have been a lot lighter still if the designers had dispensed with the bulky electrically operated Vario metal folding roof that only Mercedes provides in this segment. It eats into boot space and makes it impossible for this car to offer the pair of occasional rear seats you'll find in competitors from Jaguar, BMW and Porsche, but it's also one of the things that most appeals about this car to city-based buyers. The mechanism is still slower than a fabric hood would be and, unlike a rag top, has the disadvantage that it can't be operated at slow speeds on the move. However, it was speeded up in this generation model to raise or lower the elaborate metal panels in a respectably rapid 20 seconds.
Of course, in our miserable climate, you'll be travelling top-up rather a lot of the time but at least when you are, there'll be more of a light and airy feeling if you've got a car whose original owner ticked the box to specify the roof either in panoramic glass form with a draw-across blind or, even better, with what Mercedes calls 'MAGIC SKY CONTROL'. It's a neat touch that uses electro-reactive particles to switch the roof panel from light to dark at the press of a button. Which means that roof-up motoring can be a little more pleasant.
The designers have also applied themselves to making the al fresco experience more agreeable. Top-down, you will, for example, be better able to appreciate the surround sound stereo thanks to a clever Frontbass system which takes the front bass speakers from their usual position in the doors and mounts them in aluminium structures in front of the footwells which then become resonance chambers, delivering crisp, concert hall-standard sound even at the fastest speeds. Even neater is the way that you don't get splashed when the roof's down and you operate the wiper jets thanks to the way that a 'Magic Vision Control' system jets the fluid directly out of a wiper blade that can even be heated to prevent snow or ice forming on it in winter. There's also the neat AIRSCARF neck-level heating system that'll make you more tempted to travel top-down on chilly mornings. It was optional when this car was new but most owners paid extra for it.
Some things haven't changed though. This is the most spacious car in its class for front seat occupants, even more so since this generation version grew by 50mm in length and 57mm in width. The result is the most un-sportscar-like feeling of being able to spread out a little within the beautifully-finished cabin. The fact that this interior must be appropriate to an exalted supercar price tag pays big dividends if you're buying at the bottom end of the SL line-up, where it feels a class apart from that of a rival Jaguar XK or BMW 6 Series from this era. As with the more exalted SLS AMG, influences have been drawn from the world of aviation, with gorgeous jet-turbine-style air vents dominating a wing-shaped dash with a centre console modelled on the flight deck of an aircraft.
Ahead of you lies a three-spoke Nappa-leather-trimmed flat bottomed multi-function sports steering wheel through which you view a set of classic back-lit dials with three dimensional graduated rings. To your left, the dash is dominated by the huge COMMAND infotainment display screen the controller for which is down near the small but exquisitely-styled DIRECT SELECT gearshift lever. The only change we personally wouldn't have made is the addition of an electrically-operated parking brake. Still, that has freed up more cabin storage space. Talking of which, the fact that there's only room for two people in here does at least free up room for a lockable box behind the passenger seat for keeping valuables away from prying eyes.
Larger items of course, will need to go rearwards and if you approach the composite bootlid laden with them, then you'll be glad if you've got yourself a car fitted with the optional HANDS FREE ACCESS system that'll raise - and shut - the trunk with just a wave of your foot beneath the bumper, providing the car key's in your pocket. Once open, the regulatory two golf bags will be no problem, for there's 364-litres of room on offer. That's 129-litres more than the previous generation SL could offer, something that, rather against expectations, means you actually now get more trunk room in this car than you would from rag-top rivals from this era like convertible versions of the Jaguar XK and the BMW 6 Series. That's roof-down, in which configuration you can press a button to tilt the roof stowage sandwich 25-degrees upwards for easier loading. With the roof-up of course, there are no such issues and the total boot capacity figure increases to 504-litres.
What to Look For
Most SL owners of sixth generation cars seem to be very satisfied people. There were a few niggles though. We came across one owner who complained about the indicator stalks not cancelling after cornering and said he sometimes lost sound from the audio system after engine start. Another complained that his SL's auto gearbox occasionally locked itself in 'Park' - apparently that's a known fault. In that case, the gear selector mechanism had to be replaced under warranty. The same car was recalled for two front suspension arms to be upgraded due to a bush problem.
The Vario roof seems to work well, but 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.
The quality of the interior is also a good deal better than it was on earlier SLs. 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.
(approx based on a 2013 SL500 inc VAT) Air filters are around £16. Oil filters cost around £25. Brake pads are around £125 for a set. An oil pump is around £30 and tyres are around £35 to £45 each if you go for a cheaper brand.
On the Road
So to the SL experience. Whether or not you see this as a 'sports car' or a 'sporting car' (and there is quite a difference), a journey in one of these remains a very special experience indeed that begins with a silver starter button. A touch upon it reveals a muted muffled roar from beneath the enormous bonnet that stretches out before you, tonally tuned by the size of the engine you've chosen. Perhaps the 306bhp 3.5-litre V6 of the entry-level SL350, a variant that was quickly replaced by a 333bhp SL400 derivative. Or maybe you'd prefer the 435bhp output of the 4.7-litre twin-turbo V8 SL500. There are AMG options beyond this to try and snare the supercar set: namely the 5.5-litre V8 of the SL63 AMG which can put out as much as 564bhp. Or if you really must, the 6.0-litre V12 of the 630bhp SL65 AMG.
All the engines on offer manage faster yet more efficient figures than was possible with the units used in the previous fifth generation SL, courtesy of lighter space-age aluminium underpinnings. There were some fundamental changes to the engineering dynamics of this MK6 model too, primarily a wider track for greater stability, Torque Vectoring Brakes for tighter corner turn-in and the fitment of standard semi-active adjustable damping that enables you to match the ride you get to the mood you're in and the road you're on, across a wide spectrum ranging from pillowy 'comfort' to tauter 'Sport'. If 'pillowy comfort' isn't an option you're likely to be using very often, then it might be worth finding an SL whose original owner paid extra for the optional 'AMG Sports package'. This featured lowered suspension and stiffer springs.
Personally though, we think you'd do better by finding a MK6 SL whose original owner was wise enough to pay extra for the Mercedes' 'ABC' 'Active Body Control' system. This effectively does the whole suspension-setting thing for you, using sensors to measure the movement of the wheels and the forces acting on them before 'actively' moving the wheels up and down to compensate for body movements. The result is the kind of cornering-on-rails feeling you'd get if you set the suspension up to be rock-hard, yet at the same time, the kind of supple ride you'd expect with the dampers set on 'comfort'. The system automatically lowers the car at speed to bring down its centre of gravity and can be raised for greater ground clearance over rough roads. In other words, it's very clever indeed.
Even without 'ABC' though, the result of Mercedes' efforts with this much improved SL is a car you feel much more confident in driving quickly. True, it's still not as agile as a Porsche 911, nor is the response from the improved Direct Steer electromechanical steering anything like as good, but the dynamic gap between these two cars was certainly narrowed in this era. Which was just as well because the MK6 version of this Mercedes did offer significantly more power than its predecessors under the bonnet. Set the silky-smooth 7G-TRONIC auto gearbox into its most responsive 'Sport' mode and even the entry-level V6 SL350 is capable of 0-62mph in 5.9s, only a second and a half slower than the biturbo V8 SL500 model.
If that's really not enough and you want to properly reward yourself, then the V8-powered SL63 AMG can rocket from rest to 62mph pretty much as quickly as the V12-engined SL65 AMG flagship variant, rest to sixty two demolished in as little as 4.3s. And you can go faster still if you find a car whose original owner specified the extra-cost AMG Performance package with its extra 27bhp. This doesn't do much for the acceleration but it does remove the 155mph limiter that all SLs otherwise have, raising the ultimate velocity to 186mph for those who've a dragstrip to hand - or merely possess a particularly long driveway.
In any SL with the roof down, the engineers claim that up to 125mph, cabin occupants will remain unruffled and easily able to converse. When you do want to operate the Vario top, it's slightly annoying that, in contrast to rag top rivals, you have to stop before the mechanism will work. Still, the process only takes 20s and once all the panels have slotted Swiss army knife-style into place, there's the folding hard-top advantage of greater roof-up refinement than a fabric convertible could provide, something further aided by the fitment of acoustic film in the laminated windscreen.
This is a very special car - and not only because it was the first large-scale production Mercedes-Benz with an all-aluminium body. Like its predecessors, the sixth generation SL offers a unique, fascinating and in some ways contradictory interpretation of sportscar motoring. It's not really suited to a track, yet it's more than just a very grand GT, a combination that won't suit if your preferences lie at either of these extremes. For many though, this will be the perfect way to reward themselves for a lifetime's endeavour, a car that feels genuinely coupe-like with the roof up and roadster-ready, top-down.
Nothing else in this segment from the 2012 to 2016 era manages that quite as well. Nothing else can offer the security of a hard-top folding roof and, rather surprisingly, nothing else comparable is either as well equipped or as efficient to run. This is then, an enduring but very modern take on luxury sportscar motoring. And every inch a Mercedes-Benz.
Mercedes-Benz SL [R231] (2012 - 2016) review by JONATHAN CROUCH