Used Mercedes GLS 2015-2020 review

There are large luxury SUVs, and then there's the Mercedes GLS. It's humongous, so no wonder it can seat seven in comfort and still have room for holiday luggage in its boot. You might recognise this car's predecessor, the GL, but a facelift and the adoption of even more opulence in 2015 updated the moniker to GLS.

Buyers can, from new, choose between a 350d version, with a 3.0-litre V6 diesel, a 400 version with a petrol engine and a superfast 557bhp 5.5-litre V8 petrol GLS 63, all models coming with a nine-speed automatic gearbox and all being four-wheel drive.

Three trims are available on your new GLS – AMG Line, designo Line and the AMG breathed-on GLS 63. The entry-level model gets 21in alloy wheels, adaptive air suspension and LED headlights, a panoramic sunroof, a sports braking system and an aggressive AMG bodykit on the outside, while inside there is a 360-degree camera, tri-zone climate control, heated seats all round, a Harman and Kardon sound system, and Mercedes-Benz’s 8.0in infotainment system with DAB radio and Bluetooth connectivity. Upgrade to the more luxury appointed designo Line and your GLS gains Mercedes’ active curve system, limiting body roll and increasing agility and safety. There is also ventilated and massaging front seats, four-zone climate control, temperature-controlled cupholders, rear sunblinds and a luxury quilted leather upholstery. Those looking for the almost unbelievable combination of battleship-size and supercar speed might consider the GLS 63, with its aggressive bodykit, high-performance braking and exhaust system and AMG-embossed sports seats to go alongside the 5.5-litre V8 under its bonnet.

On the road, the GLS is smooth and refined, if not, as you might expect given its girth, an outright ball of fire. It steers well, and its handling is safe and secure, even if it’s not particularly agile or keen to change direction and it’s definitely not possessed of the sort of set-up to please a keen driver. It rides well, though, and in Comfort mode there’s only the odd shimmy over very bad bumps. Indeed it sponges away most large obstacles with ease and is remarkably settled on the motorway. Switching to Sport adds stiffness to the dampers and causes more jostling over cracks and potholes.

Inside the beast, the driver benefits from an electrically adjustable seat and steering wheel to ensure a huge range of possible positions. Visibility is good all-around, helped by a standard 360-degree camera. The new 8.0in screen and digital instrument cluster readout is much sharper than on earlier GL models and more easily navigated using a solid, metallic rotary dial and a new multifunction steering wheel. Most of the dash and door materials look and feel high-quality, too, such as the stitched-leather dash and wood trims, but some of the switchgear plastics and the odd sharp edge let the side down.

Space, however, is deeply splendid. There’s loads of room up front, and plenty of room for three adults in the second row. The third row also has room for two adults, and getting in and out of there is also easy thanks to the electrically adjustable seats in the middle row. Boot space with all seven seats in place is good, with enough for a couple of medium-sized suitcases, while with the rear two seats folded away it’s huge.

This generation was replaced by an all-new model in 2020.

If you're interested in finding a used GLS, or any of the other SUVs mentioned here, head over to the Used Car Buying pages to find lots of cars listed for sale at a great price.

You’ll need around £37,000 to get behind the wheel of a GLS. This should buy you one of the 2015 or 2016 cars with an average mileage for the year and a full service history. Spend a little more than this to buy one from a franchised dealer, and pay between £40,000 and £45,000 for a 2016/2017 model. Spending above £45,000 should buy you a 2018 or 2019 model from a Mercedes dealer.

MPG

On paper the diesel 350d is the most economical, with an official figure of 37.2mpg and corresponding CO2 emissions of 199g/km, under the old NEDC calculations. You are unlikely to better 30mpg in the real world. Only consider either of the two petrol-engined versions if you have access to your own private oil well.

Road tax

Expect annual car tax bills to be high. If your GLS was registered before the tax changes of April 2017 came into force you’ll pay a hefty premium based on the car’s CO2 emissions. If it was registered after that date (up until April 2022), you’ll pay a flat-rate fee currently £165 a year as well as a luxury car tax supplement for cars costing over £40,000 which currently stands at £335 per year for year's two to five of the car's life.

Servicing and insurance

Likewise, expect insurance to be high, and servicing costs too, although there are a number of specialist dealers who’ll service your Merc at a cheaper price than the main dealers.

We would seek out a 350d diesel-engined car, as its running costs, while huge, are moderate compared with the petrol-engined alternatives. AMG Line trim is comfortably equipped and worth looking for too.

Our favourite Mercedes-Benz GLS: 350d AMG Line

The Audi Q7 is much more than just your typical luxury SUV. It rides like a limo, has excellent straight-line performance and masses of space inside. It also delivers sublime refinement and is well equipped.

The Volvo XC90 is a hardy perennial in this class. It’s big, classy and has a spacious interior. It’s well equipped and, like the Q7 and the GLS, has room for seven. Like the Q7, it’s cheaper to buy and should prove cheaper to run than the GLS.

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If you're interested in finding a used GLS, or any of the other SUVs mentioned here, head over to the Used Car Buying pages to find lots of cars listed for sale at a great price.