Mercedes-Benz GLS 2020 Review

Once upon a time European cars were dinky little things and Euro brands didn’t build SUVs. The new Mercedes-Benz GLS 400d illustrates how much things have changed.

The third generation of the large luxury SUV once known as the GL lands in Australia measuring up at more than 5.2 metres long, nearly 2.0m wide and weighing in at about 2.5 tonnes.

It can accommodate up to seven adults across three rows of seats and still fit as much luggage behind them as an A-Class at the same time.

It’s all somewhat gigantic. But not unusual in the era of the BMW X7, Audi Q7 and forthcoming Q9, and other over-sized SUVs like the mega-expensive Bentley Bentayga.

Mercedes-Benz’s SUV flagship rolls on an extended version of the same new MHA architecture as the latest GLE (or ML in a former life) launched in Australia in 2019.

The GLE has somewhat crowded in on the GLS in this generation. It now can be had with seven seats and the same 3.0-litre turbo-petrol and turbo-diesel inline six-cylinder powertrains.

Partly as a result of that Benz has moved the GLS further upmarket. Where pricing for the previous generation started under $120,000, the mild-hybrid GLS 450 gets the ball rolling this time round at $146,500 plus on-road costs.

The 400d being tested here tops that at $153,300. By the way, both those prices have already inched up a couple of grand since Australian pricing was first announced back in November.

If that’s not expensive enough for you then watch out for the 4.0-litre V8 turbo-petrol Mercedes-AMG GLS 63 and the mild-hybrid V8 Mercedes-Maybach GLS 600 coming in the third quarter of 2020.

At the core of the GLS 400d is the new OM656 I6, which produces 243kW and 700Nm and drives all four wheels via a nine-speed automatic transmission and fully variable 4MATIC all-wheel drive.

Benz claims a 7.7L/100km combined fuel consumption rate for the 400d, but good luck achieving it. Our average during a one-day 300km drive that included very little stop-start stuff came out at 10.2L/100km. Use this thing as a commuter and it should climb again.

Nevertheless, this is a hugely impressive powertrain. Benz claims a 6.3sec 0-100km/h time, which undersells it a bit. Powerful yet surreptitious, it has so little tip-in turbo lag that the immediacy of response surprised more than once. Being a nine-speed, the auto changes gear a lot, but not so you’d notice unless you are paying attention.

As is the Benz way, the gear selector is mounted on the right-side of the steering column, which means manual shifts are only achievable via paddles. You’re rarely if ever going to feel compelled to use them.

The Mercedes-Benz GLS uses a monocoque chassis, steers via a power-assisted rack, rides on air springs and adaptive dampers and rolls on 21-inch wheels as standard, or optional 22s or 23s. The latter is a first for Mercedes-Benz in Australia.

Our test car came with 22-inch Continental Premium Contact 6 R-rated rubber that measured 285/45 up front and 325/40 at the rear. Just once, we’d love to see someone offer 17-inch steelies and a tyre with a lovely big cushioning sidewall on a car like this.

The GLS floats along in comfort mode over most standard road surfaces, but it does crash pretty hard into sharp-edged potholes and laterals. It’s the tyre and the weight overcoming the capacity of the suspension to cope. Flick into sport and there’s more patter on smooth surfaces and the same crashing through the big stuff.

We did have a drive on gravel in the GLS. There is an off-road mode that raises the car. But on ultra-dry pea gravel it just skated around, suggesting the tyres weren’t loving the experience.

If you want to get serious you can option a $3500 off-road engineering package that includes low-range gearing and the hellatiously expensive $13,000 E-Active body control including a suspension bounce mode to help extricate you from sticky situations. But really, why would you?

More appealing is the $1900 towbar pack that enables you to exploit the 400d’s 3500kg braked towing capacity. A space-saver spare tyre is standard, by the way.

The tyres are the main contributor of noise to an otherwise hushed cabin. On coarse-chip roads, there’s quite a roar. The engine, by contrast, only really becomes discernible above 4000rpm – somewhere you won’t be often while cruising.

And cruising is the GLS 400d’s forte. Sure, it’s surprisingly lithe for its size on a winding road, but physics set strict limitations. It will have a couple of goes at settling after a bump and the brakes have a big job to retard all that weight.

In town, in the tight stuff, it’s just about as big as you want to go. Yes, it’s a high and clear viewing platform and there’s lots of sensors and cameras to assist manoeuvring, but it’s just big.

Of course, that size assists the Mercedes-Benz GLS 400d inside the cabin.

There are three rows of seats arrayed in a 2-3-2 formation. The five seats across rows two and three can be power-folded flat individually or as one. The luggage capacity goes up from 355 litres to 840 litres and then all the way to a huge 2400 litres with only the front row seats in place.

The loading space is flat and 2.2 metres long, which means you could easily sleep in there if you wanted.

Keep the seats in place and you really can fit a full-size adult in row three. Benz says they can be up to 194cm (six feet four for the oldies), but even with the middle-row seat pushed as far forward as possible that would be tight. So short journeys only for the beanpoles, but the kids would be fine for days.

Entry and exit from row three is pretty straight forward thanks to giant rear doors and second-row seats that flip forward well out of the way.

In row two it’s hard to imagine anyone ever complaining about a lack of space for their head and legs. Girth might be an issue if three solid blokes try to nestle in here. But three kids? No drama.

Speaking of kids, there are top-tether points for all five seats across row two and three, and ISOFIX mounts for the four outboard seats.

And the row one perspective? Well, there are no problems in terms of getting comfortable in supportive leather seats that offer a hot stone massage (yep) and a whole lot more, it’s just coming to terms with all the tech that’s the challenge (more on that shortly).

The detritus of modern life we all drag into our cars should be accommodated within the GLS quite efficiently. The gear selector position allows for a giant centre lidded bin up front, supported by a huge glovebox and wide door pockets.

There’s storage in row two in the back of the centre console box, in the doors, the fold-down centre armrest and in string nets. There are also two cup-holders in row three.

Passenger comfort is looked after by five-zone climate control – which means people in row three can set their own temperature. There seem to be vents everywhere in this thing. There are also seven USB-C points spread through the cabin.

Benz claims communications across all three rows are aided by the microphones of the 13-speaker Burmester sound system, which picks up speech and outputs it “in all directions”. Not such a good idea if you’re sitting up the back quietly slagging off the driver’s skills!

That brings us to equipment. Predictably, the Mercedes-Benz GLS 400d has a lot of it.

Let’s start with safety. There are nine airbags that stretch all the way back to row three. Driver assist systems include autonomous emergency braking, active lane keeping and lane change assist, evasive steer assist and rear cross-traffic alert.

There’s also route-based speed adaptation, which means the car will use sensors and map data to figure out if there’s an obstacle – such as a T-intersection or corner coming up – and then slow itself.

Throw in adaptive cruise control and that lot adds up to pretty impressive semi-autonomous capability. The GLS happily negotiated a curving country road during our test, sitting approximately in the centre of the lane. Lesser vehicles would have been pinballing from side-to-side and then simply spearing off-road.

The only time there was an issue came when a vehicle appeared from around a corner and the GLS thought it was on the wrong side of the road – it wasn’t. As a result it slammed on the brakes for no good reason. It was a Ranger Raptor coming the other way so maybe the GLS was just awestruck.

Key comfort and convenience equipment not already mentioned includes standard AMG-Line exterior trim so you get colour-coded wheel-arches and the like, 64-colour interior ambient lighting, a panoramic sunroof and a comprehensive media system that includes Apple CarPlay, Android Auto and Benz’s AI-powered MBUX infotainment set-up.

So to the complexity. There are two 12.3-inch digital screens spread across the dashboard. One of them is an instrument panel in front of the driver containing two faux-analogue dials split by a central readout. The look of the entire screen or individual aspects of it can be tailored to suit your needs and wants. This is achieved via swipe and tap buttons on the steering wheel.

It would be a good idea to sit and play with this stuff for a while before you hit the road, because it can be distracting if you’re not sure what you’re doing.

The second screen atop the centre stack now has touch functionality. It can also be controlled by voice, by a dial and by a remote touchpad – and probably other ways too. Some functions in the GLS can also be operated by gesture control.

Again, drive around before you go driving around – if you get what I mean. The shortcuts button to key functions quickly became my favourite.

And what of the MBUX voice control that Benz hypes as being more intuitive than ever before? The key thing is it responds to natural speech. For instance, tell it you’re cold and it will bump up the heater.

Look, it’s impressive, but it only operates within certain defined roles. You’ll quickly figure out what they are. It also has the annoying habit of interrupting conversations to ask what you want. And then asking again if you don’t respond. Over time it does become more intuitive, but we didn’t spend enough time with the GLS to test that out.

The Mercedes-Benz GLS 400d is big in exterior size, interior space and price. Once driven, it demands respect for its sheer competence and capability.

But the reality is it’s more than most people will ever need or want. Thankfully, the Europeans still build small cars!

How much does the 2020 Mercedes-Benz GLS 400d cost?
Price: $153,300 (plus on-road costs)
Engine: 3.0-litre inline six-cylinder turbo-diesel
Output: 243kW/700Nm
Transmission: Nine-speed automatic
Fuel: 7.7L/100km
CO2: 202 g/km
Safety rating: N/A

Related reading:
Mercedes-Benz GLS Review
Mercedes-Benz GLS Video
Mercedes-Benz GLS News