Parkers overall rating: 4 out of 5 4.0

Miles per pound (mpp) Miles per pound (mpp)

Diesel engines 5.5 - 5.9 mpp
Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Fuel economy

Diesel engines 27.4 - 29.4 mpg
  • Diesel is best, but still thirsty
  • Deep pockets required for GLS 63
  • No plug-in hybrid option here

Mercedes-Benz GLS SUV running costs

Chances are you’re unlikely to be considering running a Mercedes-Benz GLS as a company car unless you own the company, so it’s well-heeled private buyers who are most likely to take the plunge.

Do not lose sight of the fact that this is a large, heavy SUV, meaning it get through tyres and brake components at a quicker rate than an executive saloon. Plus, because they’ll be bigger, you’ll pay more for them.

So, what of the engines? With a claimed 35.3mpg and CO2 emissions of 203g/km, the GLS 350 d is the more sensible of the two options. Just be aware that out in the real world you will struggle to top 30mpg.

If money really isn’t much of a factor, then why not revel in the V8 rumble of the Mercedes-AMG GLS 63? On paper it should average 23.0mpg, but in reality you’ll struggle to get out of the high-teens.

Ordinarily large, luxury cars tend to lose colossal amounts of their brand new price in depreciation, but because the GLS is a fashionable SUV it retains an impressive 50% after three years and 30,000 miles of use.

Mercedes-Benz GLS SUV eco credentials

If you’re looking for a low-emission SUV then stay away from the Mercedes-Benz GLS – neither of the two engine options are capable of delivering sub-200g/km of CO2, even with a standard stop-start system.

Best of the pair – still with a heady figure of 203g/km of CO2 – is the GLS 350 d with its 3.0-litre diesel engine.

At the opposite end of the scale, churning out 288g/km of CO2, the V8-propelled Mercedes-AMG GLS 63.

Despite its expertise in plug-in hybrid and fully electric drivetrains, the GLS is not available with such a system to reduce CO2 emissions. If that’s a prerequisite then you’ll have to consider the smaller Mercedes-Benz GLE which is available in plug-in guise.

  • Strong reliability record for the GLS
  • Only one official recall since its launch
  • Major components used across the range

Mercedes-Benz GLS SUV reliability

There isn’t a lot to complain about in terms of the Mercedes-Benz GLS’s reliability. While it’s rammed with electronic systems and features, it’s a robustly built machine and feels of a very high quality – as you’d expect from a car at this price point.

The engines and transmissions see service elsewhere in the Mercedes range, so longevity shouldn’t be an issue there either.

So far there’s been only one official recall concerning GLS models (as well as the E-Class and GLE) built between August 2015 and July 2016 relating to a power steering defection. All of those affected models should now have been remedied.

Ongoing running costs

Road tax (12 months) £305 - £475
See tax rates for all versions
Insurance group 50
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