Mercedes-Benz SL-Class Review (2012-2021)
Mercedes-Benz SL-Class cars for sale
4.0
Expert review
Pros
As capable as it is desirable
The benefits of a roadster and a coupe in one
Epic performance of AMG SL65
Cons
Not as dynamic or sporting as a Porsche 911
High running costs
The AMG's performance overstretches the chassis
The CarGurus verdict
There aren’t many cars which can genuinely be labelled iconic, but the SL is one of them. A hugely capable, very desirable roadster and coupe in one, it might not be as dynamic or as sporting as rivals like the Porsche 911, BMW 6 or 8 Series, or quite as luxurious as something like a Bentley Continental GT, but it’s so rounded that it’s a difficult car to find fault with.
The V6 is appealing, but the V8 in the SL500 is the car we’d want. The AMGs, for all their thunderous soundtracks and ludicrous performance potential, ask questions of the SL’s chassis that, ultimately, it fails to answer convincingly. The SL is at its best as a dignified grand tourer, perfect for a lengthy cruise around Europe or any of the world’s wealthy hotspots, or, simply a go-to indulgent drop-top for weekend fun, or, indeed, as a daily driver. The SL’s strength is in its adaptability and useability.
When this generation of SL (known to experts as the R231) was introduced, it brought back some of the lightness that had been lost with previous versions to the SL badge, with Mercedes making it almost entirely out of aluminium. This is to the benefit of both performance and fuel economy, while the SL has also been something of a standard bearer for Mercedes-Benz’s latest technology, with things like Active Body Control (an active suspension system) being available as an option.
Even so, the SL in R321 form isn’t the most sporting car among its contemporaries – even the AMG variants, with mighty power outputs and Active Body Control (standard on these models) tweaked to suit their more sporting character, weren’t the equal dynamically for the best sports cars out there.
That’s not to say the SL can’t be engaging and enjoyable to drive; it can, and is, remarkably capable when driven enthusiastically. It’s just that it doesn’t feel like a car that should be driven that way. Its strength lies in its comfort and ease, and, for a two-seater at least, surprising practicality.
Naturally, the infotainment system was comprehensive for the time it was sold, the SL quick to adopt things like Apple Carplay and Android Auto, so check if any used example comes so equipped.
While the folding hardtop gives you the option of a cool coupe or open roadster, Mercedes' engine offering with it allowed you to experience the SL in everything from a brisk, easy cruiser, to an absolute monster. During its ten-year production run it was available in SL350 guise with a 3.5-litre turbocharged V6 with 302bhp, the SL400 with a 3.0-litre bi-turbo V6 initially offering 329bhp though latterly with 367bhp, and the SL500 with a 4.7-litre bi-turbo V8 with 429bhp (later 455bhp) – the SL500 being badged SL550 in some markets. If they’re not enough for you, Mercedes-AMG’s involvement included the SL63 with a 577bhp 5.5-litre bi-turbo V8, or the monstrous SL65 AMG, which upped the cylinder count to 12, with a 621bhp 6.0-litre bi-turbo V12 powering it. Initially the SL-Class came with a 7G-Tronic seven-speed automatic gearbox, but in later years it came with a 9G-Tronic nine-speed auto, the SL also getting a subtle facelift to bring a slightly new style during its production run. The AMGs got their own AMG-Speedshift versions of the automatic, all SLs being rear-wheel drive.
As a minimum the first owner will have dropped a not insignificant £75,000 on the SL when new for one of the entry-level V6 models. A V8 adds to that, while the AMG models would have been even more expensive, the AMG SL65 quite terrifyingly so. All that means you can chuck out any expectations of inexpensive running costs, whether it’s in relation to fuel consumption, insurance, servicing or maintenance.
Thing is, it’s a rarified marketplace, and buyers will be only too aware that buying and running an SL won’t be an inexpensive undertaking. But conversely, maintain it properly, and it’ll do you years of service, and likely eventually start appreciating in value as they become sought-after classics. However you justify it to yourself, or your partner, there’s some merit in it.
Obviously the V6s will be the least expensive to buy and run, their fuel consumption better, but still hardly what you’d call parsimonious, with the SL400’s combined consumption figure quoted at 36.7mpg. That’s via the old measuring system, though, so a more realistic daily driving mpg figure will be in the mid-to-late 20s, with it dipping below that and into the teens if you happen to be in a hurry. The SL500’s consumption will be worse, figure on about 10-20% worse than that SL400. Indeed, the final SL400 and SL500 models were sold while WLTP combined consumption figures were introduced, the SL400 quoted at 28.8-29.7mpg and the SL500 26.4-27.4mpg. And those AMGs? They’ll burn through super unleaded like Saturn 5 does rocket fuel.
Servicing can be inexpensive, with Mercedes-Benz offering fixed-price, monthly payment plans for servicing if it’s still within the dealer network. Outside it, a number of independent specialists will be able to work on your SL, too, for less than main dealer pricing. Even as a used car, many will still have the balance of the Merc warranty, too.
The SL’s longevity, it typically being offered for a decade compared with most cars’ production runs of around five to six years, plays into its favour for reliability. Any gremlins experienced with the earliest cars will have been well and truly ironed out by the time the SL reaches the mid-life cycle, that only likely to improve with the later, facelifted models which benefit from additional development time.
As such there aren’t any real worries about buying a used SL, it just being a case of being sensible, checking it’s been maintained meticulously and checking that all the electrical systems – of which there are plenty – all work.
Be sure to check the folding roof operates, as it can seize if it’s not used frequently, say, if it’s laid up over winter. Likewise, be sure to check the full range of movement in the electric seats, and don’t wait until winter to try the button for the heated seats and suchlike, do so even if you’re test driving it in the summer, as well you might be. The engines are all proven units, likewise the transmissions, again, though be sure to have a good look at the service history.
It’s well worthwhile, and cost effective in the long-run, to have a specialist have a thorough inspection of any prospective purchase before you do so, the small initial outlay potentially saving you future expense, or giving you a bargaining chip with which to get a better deal if they spot work needing doing.
Mercedes overall scores rather poorly in manufacturer reliability surveys these days, with it typically in the bottom third of all manufacturers. Any recalls relating the SL should have been undertaken, but if you want to check you can do so by giving your Mercedes-Benz dealer a call with the VIN (Vehicle Identification Number) for your SL to be sure. Overall, it’s beautifully engineered, so it should prove reliable.
- In Mercedes speak the most recent SL to be available was the R231 model, which was preceded by the R230, its lineage traceable back through five other generations. Each model arguably defined its respective era, be it the fast, advanced sporting ‘Gullwing’ 300SL of the '50s which was raced with international success, its gorgeous ‘Pagoda’ W113 replacement throughout the '60s, the R107 which spanned two decades from the early '70s to late 1980s to the R129 from 1989-2002, and the R230 which was available from 2002-2011.
- Safety has always been a big part of Mercedes' core values as company, and that’s even true with something like the drop-top SL-Class. Along with an active bonnet that pops up to help in a pedestrian impact, there is a pair of roll bars that pop out of the rear in the event of a roll-over. Mercedes-Benz’s anticipatory system Pre-Safe is also standard, as is a driver monitoring Attention Assist. In addition there are a host of other passive and active safety aids available including blind-spot monitoring, Active Brake Assist and many more as part of the Driving Assistance Package, this a sports/GT car with impressive safety credentials.
- The name might mean sports light, but it has heavyweight levels of equipment, particularly in relation to comfort and luxury. The standard seats offer a huge range of electrical adjustment and heating, and if optioned, can also be ventilated, both conventionally via the seat back and base, as well as a technology Mercedes calls Airscarf. That Airscarf blows warm air over your neck and shoulders, allowing you to enjoy your SL roof down more of the year. Opt for those, and the massaging function as well, and you’ll be so comfortable that you’ll never want to get out of it.
- The all-rounder: While it’s easy to be seduced by the V8 in the SL500, the SL400 is as able, and a little bit more agile, too. With 367bhp on offer from its twin-turbo 3.5-litre V6 engine, it’s no slouch, being able to reach 62mph in a respectable 4.9 seconds, and onto an electronically limited 155mph top speed.
- The monster: If you absolutely have to have the most powerful, most expensive and greatest number of cylinders with your Mercedes SL, then accept nothing less than the AMG SL65. With a 6.0-litre V12 under its bonnet with a pair of turbos upping the power, the SL65 pushes out a quite ludicrous supercar rivalling 621bhp, that underpinned by 738lb ft of torque. They’re rare, for good reason: the SL65 commanded a price tag in excess of £160,000. And while it’s the most powerful, it’s not the best.
- The most sporting: For that you need the SL63 AMG, it not having the same mighty output as the SL65, but 577bhp isn’t too much of a drop in power, while it’s also quicker in the 0-62mph sprint, covering it in 3.7 seconds in comparison to the SL65’s 3.9 seconds. Without a big V12 up front, the V8-engined SL63 is an easier, more engaging car in the bends. That’s relatively speaking, of course. The SL is not an out-and-out sports car: for that you should look at an AMG SLS, or latterly the AMG GT, or any number of alternatives from Porsche, Ferrari, Maserati, Jaguar, Audi, Bentley and BMW, among others.
- The classic: The definitive SL is a dignified, easy, brisk machine with a V8 under its bonnet, and that’s exactly what the SL500 is. None of the overt style of the AMG models, though with 429bhp it’s quick and easy, and likely to be the car that’ll be considered the archetypal SL when it reaches the status of a being considered a classic. Buy it in final Grand Edition form, and you'll only add to its collectability in the future, too.
