What's the news?
It started life as a GL-Class and then, during its second generation, it evolved into the GLS. And now Mercedes-Benz, currently in the middle of a huge SUV overhaul/onslaught (see below), is bringing us the all-new GLS, in Mk3 guise.
Exterior
The new Mercedes GLS is even bigger than it was before; no mean feat because the Mk2 was a whopper. Nevertheless, the Mk3 is longer by 77mm (5,207mm overall) and wider by 22mm (1,956mm overall), and that increase in length results in another 60mm being added to the wheelbase (now at 3,135mm). Its redesign, along the strategy of 'Senusal Purity', clearly ties it in with the mid-sized GLE, which has already been revealed in its latest form as a possible seven-seater.
However, the GLS still distinguishes itself as 'the daddy', mainly because it is supposed to be an S-Class in SUV clothes. Its upright radiator grille has an octagonal shape, while it is denoted by a pair of louvred bars, and the bonnet features a pair of strakes that Mercedes calls 'powerdomes'.
Multibeam LED headlights, with 112 LEDs per cluster, are standard fit on all GLS models and they can illuminate up to 650 metres down the road to a value of at least one lux. Daytime running lights with three LED segments are complemented by LED two-piece taillamps at the back of the vehicle, while chrome-plated underguards can be seen front and rear of the GLS.
Aerodynamically, the Mk3 GLS represents a significant improvement over its predecessor: the Mk2 had a coefficient of drag (Cd) figure of 0.35, but the new one stands at 0.32. Not only does a more slippery shape help fuel economy, it makes the GLS quieter as it cuts through the air, enhancing its sense of luxury and refinement.
Interior
That large exterior makes for an interior that would best be described as 'cavernous'. One problem with a lot of modern-day 'seven-seat' SUVs is that they are no such thing, perhaps more accurately being described as '5+2s'. This can apply to even the larger machines on sale, but no such accusation could be levelled at the GLS Mk3 - Mercedes is so confident of its proposition that it says the third row of seats are capable of taking two adults of up to 1.94m (that's 6ft 4in!) in the back.
There's also 87mm more legroom in row two, if the middle seats are as far back as they'll slide. All three rows are fully electrically adjustable (and electric folding, where applicable), an Easy Entry function allows access to the rear-most pair of chairs to be a little more dignified and even those sitting at the very back of the GLS will enjoy heated seats and USB charging sockets.
Beyond this, the GLS Mk3 gains the full MBUX operating system, although it's upgraded from its A-Class applications as it has the full Widescreen Cockpit array of a pair of 12.3-inch monitors (the console item in an A-Class with MBUX is 10.25 inches). Furthermore, the GLS's MBUX also incorporates MBUX Rear Seat Entertainment, bringing in 11.6-inch touchscreens for movies, music and internet browsing. A Rear Comfort Package Plus also includes a tablet, which can control all of the MBUX comfort and entertainment functions from the rear seats, while five-zone (FIVE!) climate control is available. And, in what looks like a direct response to BMW's X7, if you don't need seven seats then there's a six-chair option that replaces the middle three-wide bench with a couple of luxury, individual pews. Besides all this, a high-res head-up display is an option and there are buttons in the boot to do two things: one folds all the seats away in one go, allowing cargo-carrying capacity of up to 2,400 litres; and the other lowers the rear of the GLS by 50mm, to allow for easier loading of heavy objects.
Mechanicals
All petrol engines to be offered in the GLS Mk3 will be electrically augmented by a 48-volt system, although here in Europe we're going to get diesels from the launch. These will both be the latest 2.9-litre inline-six turbodiesel, delivering either 286hp/600Nm as the GLS 350 d 4Matic or 330hp/700Nm as the GLS 400 d 4Matic. Both are said to deliver best fuel consumption figures of 7.6 litres/100km (37.2mpg), with CO2 emissions of 200g/km for the 350 and 201g/km for the 400; all these figures are NEDC-correlated, by the way, from WLTP testing, although the engine is Euro 6d-standard (RDE/Real Driving Emissions Step 2) compliant well ahead of the deadline.
Soon after these two, though, will come the GLS 580 4Matic. This pairs a V8 petrol engine with the EQ Boost 48V electrical stuff, to deliver best eco-stats of 9.8 litres/100km (28.8mpg) with CO2 emissions as low as 224g/km. These are not bad numbers for a gigantic, petrol-powered SUV - especially not one with a 489hp/700Nm V8 that can be augmented by another 22hp/250Nm, courtesy of the EQ Boost. Better still, the GLS 580 4Matic uses the 48V electrics to offer E-Active Body Control active suspension, which can provide the best in ride comfort, agile handling and off-road capability.
All GLS models will use the 9G-Tronic nine-speed automatic gearbox and 4Matic all-wheel drive. They will also come with enhanced Airmatic air suspension with the Adaptive Damping System Plus fitted, as well as a vast array of driver-assist safety and comfort features. Even better is the Carwash function. At the press of one button, the GLS is automatically prepped to be at its best for a carwash, in the following ways: it rises up to its tallest on its air suspension, which reduces the track widths (and therefore the risk of kerbing the alloys on those floor-mounted metal railings) due to the axle geometry - Mercedes says this also helps with visibility for the driver who's sitting higher, and it allows for any 'dirt remaining in the wheel arches from the last off-road trip' to be scoured out; it also folds in the exterior mirrors; closes the side windows and the sliding sunroof, if they're in any way open; suppresses the rain sensor information to keep the wipers stowed during the washing cycle; switches the climate control to air-recirculation mode; and, after eight seconds, it activates the 360-degree camera's front image to further assist the driver's manoeuvring into the carwash. All of these settings are deactivated automatically, once the GLS moves out of the carwash and exceeds 20km/h.
Anything else?
Mercedes presented the new GLS in one of its key markets, America, when it debuted the huge SUV at the New York Auto Show. It should go on sale in Europe in the third quarter of 2019, with all cars built in Tuscaloosa, Alabama.
And we said at the top of the piece that Mercedes was in the middle of a giant SUV programme? Well, it hasn't been long since the new GLE launched. The GLC and GLC Coupe have just been facelifted. There's a new GLA inbound and Merc has even tempted us with talk of a GLB, which would take its SUV portfolio to a dizzying eight models in total. But with good reason; since the original ML launched way back in 1997, more than five million customers worldwide have bought Mercedes SUVs.