Review and road test of the Mercedes-Benz SL400


The Mercedes-Benz SL is at its most accessible in SL400 V6 guise. Jonathan Crouch checks it out.

Ten Second Review of the Mercedes-Benz SL400

The Mercedes SL400 packs a twin-turbo 3.0-litre V6 good for 367bhp and 5000Nm. It'll crack 62mph in just 4.9 seconds and keep going to 155mph. It's a smart buy too, retaining more of its new value than any of its key rivals.


The Mercedes-Benz SL is a car that has been around for a long time across its various generations. It's a vehicle that has layers upon layers of history and it's most accessible in this entry-level SL400 guise where you get a 3.0-litre V6 engine that's now been uprated to put out 367bhp and a more sophisticated 9-speed auto gearbox mated with it. A 'DYNAMIC SELECT' driving system with five transmission modes and Active Body Control with a neat curve tilting function both claim to take this legendary sportscar to a new dynamic level and the vario-roof can now be operated at up to 25mph. Sounds pomising doesn't it? Will SL-watchers need to earmark this one for future greatness?

Driving Experience

Power comes courtesy of a twin-turbo 3.0-litre V6, the days of the badge on the back of a Mercedes giving a reliable clue to its engine displacement having long since passed. Still, as Lewis Hamilton and Nico Rosberg would doubtless attest, Mercedes clearly knows a thing or two about turbocharged V6 powerplants. While this one's uprated 367bhp power output wouldn't line it up on the front row of an F1 grid, it's more than enough to let the relatively lightweight SL get a wiggle on, clocking the 62mph sprint in just 4.9 seconds, while the electronically limited top speed of 155mph is shared with even more powerful versions. There's 500Nm of torque too, 20Nm more than before, and you access it through a freshly-developed 9-speed 9G-TRONIC auto gearbox. Across the range, SL drivers benefit from 'Dynamic Select' adjustable damping, a set-up you can tweak via 'Eco', 'Comfort', 'Sport', 'Sport Plus' and 'Individual' modes to suit the mood you're in and the road you're on. Another option is 'Active Body Control' with a curve tilting function. This reduces body movement through the bends in a way that's almost eerie. These changes do much to make the SL a more involving driver's proposition. Dynamically, this car has always sat rather uneasily somewhere between a Porsche 911 Cabriolet and a BMW 6 Series, not as sharp as the 911, not as luxurious as the Six. With this improved sixth generation SL, the difference is fundamental. In this, we've a car arguably able to offer much of the best of both worlds.

Design and Build

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. Changes to this improved MK6 model include a re-sculpted radiator grille that harmonises with the now standard AMG bodystyling. Two powerdomes on the bonnet invoke the sporting heritage of the SL, while light-catching contours give additional structure to the bonnet. Also adding to the revised appearance of this SL is the standard-fit LED Intelligent Light System with its headlamp housing extending far to the outside and an integrated torch-shaped unit comprising the daytime running lamp/position lamp and direction indicator. The side view of this SL reveals enlarged cosmetic air outlets with wing-like chrome inserts in the dynamic, broad vehicle wings. 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. That changed when this sixth generation version first arrived in 2012 and the decision was made to construct the car entirely from aluminium. 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 now 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 but in this model has been speeded up to raise or lower the elaborate metal panels in a respectably rapid 20 seconds. And it can now be used at speeds of up to 25mph. When up, if you've specified what Mercedes calls 'MAGIC SKY CONTROL', you'll get a neat system that uses electro-reactive particles to switch the roof panel from light to dark at the press of a button.

Market and Model

You'll need a budget of around £75,000 for this SL400. True, that's up to £10,000 more than you'd pay for a comparable BMW 640i Convertible, but we think you're getting a lot more car here. Anyway, much of that premium will be returned to you in the higher residuals you'll get at re-sale time. Of course, the main difference between the two cars is this SL's provision of a folding hard top roof. We certainly like the little SL touches that come as standard. Like 'Magic Vision Control' washer fluid jets that fire out of the wiper blade directly in front of the blade lip, in both directions of wipe. As a result, no water is splashed onto the windscreen during spraying to disrupt the driver's visibility - and you'll never fire it onto your passenger when the roof is down. You can even specify a heated wiper blade to prevent snow or ice forming in winter. Another feature that speaks volumes of Mercedes' lateral thinking is the Frontbass system which utilises the free spaces in the aluminium structures in front of the footwell as resonance spaces for the bass speakers. This gives the SL's stereo a punch while freeing up space in the doors and saving weight.

Cost of Ownership

This Mercedes-Benz SL400 is undoubtedly more powerful and, consequently, slightly quicker than the previous version, but that urge comes in tandem with reasonable frugality. Expect 36.7mpg and 175g/km CO2 emissions - not too bad for a 367bhp luxury convertible. That's almost identical, by the way, to the showing of a rival BMW 640i Convertible. Residual values of this latest SL have held up extremely well. If we take an SL400 as an example, it keeps hold of around 45% of its new value after a typical three year/30,000 mile ownership period. Its most direct rival, the BMW 640i M Sport, retains a dismal 32.3 per cent in comparison. With more power and the likelihood of better perceived value for money, the SL400 may well widen that gap even further.


The changes made to this SL won't make a huge difference to its impact on the market; you'll probably already know whether you want one of these or not. Still, extra power is always a good thing, especially if, as here, it doesn't come at the expense of efficiency. The new 9-speed auto gearbox promises smoother progress if you're cruising. And if you're pushing on a bit, the 'Dynamic Select' adjustable damping gives this car a sharper edge than it had before. As a result of all this, there's no doubt that what we have here is the best SL yet, but would you really weant this base SL400 version of it? We think we might. Do you really need any more than 367bhp in a car like this? We think not. Overall, if you thought of the SL as a bit of a gold medallion, you need to try this one. It has the power to convert the most cynical.

Mercedes-Benz SL400 review by Jonathan Crouch We will buy your car today


Car review: Mercedes-Benz SL400
Model:Mercedes-Benz SL400
Category:Luxury Sports Convertibles
Rating:8 out of 10


Car review: Mercedes-Benz SL400
Car review: Mercedes-Benz SL400
Car review: Mercedes-Benz SL400