Background
This Mercedes GLS, if you haven't yet come across it, is a vehicle billed as 'the S-Class of SUVs', a luxury conveyance for those whose real - or more likely imagined - commute to the real world is from a craggy mountaintop. We first saw it (badged then as the 'GL-Class') in 2007, the original 'X164'-series design (like the current one) built in America for Americans and since then, it's been occupying super-sized shopping mall spaces from New York to New Orleans in ever-increasing numbers. Over there, it was a necessary addition to the brand's luxury SUV line-up, given that for Yanks, the brand's usual large luxury SUV, the five-metre-long GLE, is seen as being pretty compact and the exorbitantly-priced G-Class is too crude for most.
A second generation 'X166'-series design followed in 2015, and when that model was facelifted in 2016, it was renamed the 'GLS'. The third generation 'X167'-series GLS model we have here debuted originally in 2020 and included a super-opulent Mercedes-Maybach version. It was primarily tasted with taking on the all-conquering Range Rover - and, more specifically, BMW's entrant in this segment, the X7.
This Mercedes model line has always featured a third seating row, something that's always set this SUV apart in a luxury 4x4 market that rarely offers this option - or if it does, often restricts practical use of the extra seats to children. Not so here. It's certainly more practical for seven than the brand's other super-luxury SUV of this size, the all-electric EQS SUV. In this case, we're reviewing an updated version of this MK3 GLS model, launched in Spring 2023. Let's take a closer look.
Driving Experience
Not everyone is going to feel comfortable piloting something of this size but provided you do, then GLS motoring is a pretty fabulous way to view your everyday world. AIRMATIC air suspension with the brand's 'ADS Adaptive Damping System Plus' package smoothes your way over poor surfaces and power is transmitted by 9G-TRONIC automatic transmission. The key engine option for our market is the straight six cylinder 2.9-litre diesel, provided with 308bhp with the base GLS 350d, or with 362bhp with the GLS 450d.
For those who can never have too many Tiger tokens, there's also a wild turbo 4.0-litre petrol V8 in the Mercedes-AMG GLS 63 variant, which gains 48V mild hybrid tech and puts out 612hp via a now-standard sports exhaust. The super-luxury Mercedes-Maybach version uses the '600'-badged 550bhp petrol V8.
4MATIC 4WD is standard across the range of course, which works using a transfer case with an electronically controlled multi-plate clutch. This allows a variable transfer of drive torque from 0-100 percent between the axles. Across the range, there's up to 3.5-tonnes of towing capability. As an option, buyers can specify an Off-Road Engineering package, which has been reconfigured because previoius owners didn't need to it be so extreme. Components include an underride guard and 30mm more ground clearance. And, thanks to the standard 'Parking Package' and its 360-degree camera, there's a 'transparent bonnet' function. When the Offroad mode is active, the central display shows a virtual view under the front of the vehicle. The view is composed of the images from the 360-degree camera. With the 'transparent bonnet' on the screen, obstacles such as large stones or deep potholes on the route ahead can be better recognised.
Design and Build
This revised version of the third generation model stands out with a more striking radiator grille, its four louvres galvanised with a 'Silver Shadow' finish. The bumper is also visually more prominent, featuring integrated air inlet grilles combined with a surround in high-gloss black. The large simulated underguard has also been redesigned and, as before, full-LED Multibeam headlights feature. The eye-catcher at the rear is the interior of the lights with three horizontal blocks. As before, the sheer size of this second generation GLS is imposing. This MK2 model is over 5.2m long and nearly 2m wide, but the drag factor is a surprisingly sleek 0.32Cd.
Inside, glossy brown lime wood is now standard and the louvres of the centre and side air vents are galvanised in Silver Shadow. The key difference though, is an update to the MBUX media system, which brings with it a new look for the 12.3-inch instrument screen display. This can be individualised with the help of three different styles (twin-dual 'classic', red-themed 'sporty' and minimalistic 'discreet'). Plus there are three screen modes ('Navigation', 'Assistance' and 'Service'). In addition, both the instrument screen and the 12.3-inch central display can be shown in seven colour schemes in conjunction with the ambient lighting. The result is an impressive colour experience in the interior.
Otherwise, the leather-lined cabin is much as before over its three seating rows. In the middle row, the bench can slide back and forth, while the standard third is suitable for adults of up to 1.94m in height and an 'EASY ENTRY' function now makes these rearmost chairs easier to get to.
A push of a button is all that is required to stow away the second and third row seats and make full use of the 2400-litre boot space in the GLS. The switches on the left and right of the load compartment and on the front of the wheel arches on the front-passenger side in the C-pillar area allow the seats in the rear rows to be folded completely flat.
Market and Model
Buying a GLS is pretty straightforward. Though there's a wild V8 petrol GL63 Mercedes-AMG model requiring a huge budget, almost all customers will want the more sensible GLS 450d diesel variant that you can expect to be priced in the £90,000-£100,000 bracket with mainstream trim. You'll need a lot more though, for the ritzier Mercedes-AMG or Mercedes-Maybach versions.
We haven't space here to list all the standard features, even of mainstream models - the equipment list is vast. And of course you get considerable multimedia capability, courtesy of the brand's latest 'MBUX' ('Mercedes-Benz User Experience') media screen system. This allows intuitive operation of different comfort and MBUX functions by movement recognition via a camera in the overhead console that registers movements of the driver's and front passenger's hands and arms. When a hand approaches the touchscreen or the touchpad on the centre console, the media display changes and individual elements are highlighted. A unique feature of MBUX is its ability to anticipate what the user would like next, for example. For instance, anyone who often telephones their mother on Tuesdays during the journey home will receive her telephone number as a suggestion in the display on this day of the week. Anyone who regularly switches over to a radio station with news at a certain time also receives this as a suggestion.
Our favourite standard feature though, is the Carwash function - which should come in very handy for a large vehicle like the GLS. When this function is selected, the suspension moves to the highest position, which reduces the track widths due to the axle geometry. This makes it easier to drive into a carwash as well as remove any dirt remaining in the wheel arches from the last off-road trip.
Cost of Ownership
Mercedes has put a lot of thought into trying to make this car more efficient. As a result, combined cycle fuel consumption and CO2 returns have improved significantly. For the GLS 450d 4MATIC diesel version that most will want, you're looking at around 36mpg on the WLTP-rated combined cycle and up to 210g/km of CO2. This powerful engine complies with the current strict Euro 6d standard.
This has been achieved with, among other things, an additional selective catalytic reduction (SCR) converter with an ammonia slip catalyst (ASC) in the exhaust tract of the GLS. This allows dosing of the AdBlue reducing agent that is even more closely aligned with the individual driving characteristics because any excessive ammonia surplus in the second SCR converter is broken down further. The AdBlue tank has a capacity of 31.6 litres. As before, refilling is convenient via a separate pipe behind the fuel filler flap.
What else? Well it's worth knowing that your maintenance outlay can be kept a little in check by going for the optional 'Service Care' package that takes care of routine maintenance, spreading the cost of regular servicing, guaranteeing the price of parts and labour for up to four services and covering the cost of all recommended service items such as brake fluid, spark plugs, air filters, fuel filters and screen wash.