Mercedes-Benz GLS reliability, MPG and running costs
Figures updated
The Mercedes-Benz GLS is a car. In 2024 MOT tests it scored 141 for reliability (100 is average), ranking 75 of 442, and 13.5% failed first time against a UK average of 28.5%. Its most common MOT failure is condition (2.6% of tests).
Ranked 75 of 442 cars in the 2024 MOT Reliability League
In 2024, 2,673 Mercedes-Benz GLSes aged 3 to 20 had an MOT and 13.5% failed first time (UK average 28.5%). Taking age and mileage into account, the Mercedes-Benz GLS is 29% less likely to fail than the average car of the same age and mileage. At the first MOT, at three years old, 14.5% failed (UK 12.7%).
First-time fail rate
13.5%
UK 28.5%
Fail rate at 3 years
14.5%
UK 12.7%
Average miles a year
10,200
Typical age at test: 6 years
Mercedes-Benz GLS MOT failure rate by age
Most common Mercedes-Benz GLS MOT faults
- Condition: has ply or cords exposed2.6% of tests
- Condition: has a cut in excess of the requirements deep enough to reach the ply or cords2.4% of tests
- Tread depth: tread depth below requirements of 1.6mm2.2% of tests
- Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt0.9% of tests
- Brake pads: less than 1.5 mm thick0.9% of tests
- Registration plates: does not conform to the specified requirements0.9% of tests
What the Mercedes-Benz GLS fails on
| Area | Tests failing | vs similar cars |
|---|---|---|
| Tyres | 7.7% | ▲ 1.3× as often |
| Brakes | 2.0% | ▼ 47% less often |
| Lights and electrics | 1.4% | ▼ 73% less often |
| Body and structure | 1.1% | ▲ 1.1× as often |
| Visibility | 0.8% | ▼ 77% less often |
| Exhaust and emissions | 0.6% | ▼ 61% less often |
| Suspension | 0.6% | ▼ 82% less often |
| Seat belts and airbags | 0.4% | About average |
| Wheels | 0.4% | ▲ 1.3× as often |
| Steering | 0.0% | ▼ 100% less often |
What MPG does the Mercedes-Benz GLS do?
Official economy for the Mercedes-Benz GLS ranges from 20.3 to 36.7mpg across the 16 versions listed by the Vehicle Certification Agency (2018–2025). A typical petrol version manages 21.2mpg and a typical diesel 35.3mpg. Expect 10–15% less in real-world driving.
Work out a journey's fuel costHow much is road tax on a Mercedes-Benz GLS?
Any Mercedes-Benz GLS first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz GLS registered between March 2001 and March 2017 is taxed on its CO2: £410 to £790 a year.
Work out tax for a specific carMercedes-Benz GLS specs and running costs
Official figures for 16 versions sold in the UK between 2018 and 2025.
Fuel types
Diesel, Hybrid, Petrol
Official economy
20.3–36.7 mpg
CO2
201–314 g/km
Power
330–612 PS
| Version | Fuel | Economy | CO2 | Car tax | Company car tax |
|---|---|---|---|---|---|
| GLS GLS 450 d 4MATIC367 PS · A9 · listed 2025 | Diesel | 36.7 mpg | 201g | £200 | 37% |
| GLS GLS 450 4MATIC381 PS · A9 · listed 2025 | Petrol | 28.3 mpg | 227g | £200 | 37% |
| GLS Maybach GLS 600557 PS · A9 · listed 2025 | Petrol | 20.6 mpg | 310g | £200 | 37% |
| GLS AMG GLS 63 4MATIC+612 PS · A9 · listed 2025 | Petrol | 21.2 mpg | 300g | £200 | 37% |
| GLS Mercedes-Maybach GLS 600410 PS · A9 · listed 2024 | Petrol | 20.6 mpg | 310g | £200 | 37% |
| GLS Mercedes-AMG GLS 63 4MATIC+450 PS · A9 · listed 2024 | Petrol | 21.2 mpg | 300g | £200 | 37% |
| GLS GLS 400 d 4MATIC330 PS · A9 · listed 2023 | Diesel | 35.3 mpg | 210g | £200 | 37% |
| GLS Maybach GLS 600 4MATIC557 PS · A9 · listed 2023 | Petrol | 21.7 mpg | 296g | £200 | 37% |
| GLS Mercedes-Maybach GLS 600 4MATIC557 PS · A9 · listed 2023 | Petrol | 20.3 mpg | 314g | £200 | 37% |
| GLS .5 GLS 400 d 4MATIC330 PS · A9 · listed 2021 | Diesel | 35.3 mpg | 210g | £200 | – |
| GLS Maybach GLS 600 4MATIC557 PS · A9 · listed 2021 | Hybrid | 22.8 mpg | 295g | £200 | – |
| GLS .5 Maybach GLS 600 4MATIC557 PS · A9 · listed 2021 | Hybrid | 23.7 mpg | 295g | £200 | – |
| GLS AMG GLS 63 4MATIC+612 PS · A9 · listed 2021 | Hybrid | 23.7 mpg | 286g | £200 | – |
| GLS .5 AMG GLS 63 4MATIC+612 PS · A9 · listed 2021 | Hybrid | 24.8 mpg | 286g | £200 | – |
| GLS GLS 350 d 4MATIC with 21'' rear wheelsA9 · listed 2018 | Diesel | 35.3 mpg | 203g | £200 | – |
Economy and CO2 are official NEDC (before 2018) or WLTP figures. Car tax is the yearly rate at current rates for a car first registered in the year listed, before any expensive car supplement. Company car tax is the 2026/27 benefit-in-kind rate. Showing the 15 most recent of 16 versions.
What a Mercedes-Benz GLS costs to fuel
- petrol, typical official 21.2mpg…
- diesel, typical official 35.3mpg…
Official figures are usually 10–15% better than real-world driving.
Work out a journey in a Mercedes-Benz GLSBuying a used Mercedes-Benz GLS?
Check the MOT history of the exact car: every result, advisory and mileage reading, free.
Other Mercedes-Benz models
Frequently asked questions
›Is the Mercedes-Benz GLS reliable?
Its MOT record is better than average: the Mercedes-Benz GLS is 29% less likely to fail than the average car of the same age and mileage, with a reliability score of 141 in our 2024 league (100 is average).
›What are common problems with the Mercedes-Benz GLS?
The most common MOT fault is “Condition: has ply or cords exposed”, found in 2.6% of tests.
›What MPG does the Mercedes-Benz GLS do?
Official economy for the Mercedes-Benz GLS ranges from 20.3 to 36.7mpg across the 16 versions listed by the Vehicle Certification Agency (2018–2025). A typical petrol version manages 21.2mpg and a typical diesel 35.3mpg. Expect 10–15% less in real-world driving.
›How much is road tax on a Mercedes-Benz GLS?
Any Mercedes-Benz GLS first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz GLS registered between March 2001 and March 2017 is taxed on its CO2: £410 to £790 a year.
›How many Mercedes-Benz GLSes fail their MOT?
13.5% of Mercedes-Benz GLSes aged 3 to 20 failed their MOT first time in 2024, and 14.5% failed at their first MOT.
Sources: DVSA anonymised MOT tests 2024, all versions of the Mercedes-Benz GLS combined (Open Government Licence v3.0); official economy and CO2 from Vehicle Certification Agency data, © Crown copyright. VCA cannot accept liability for its accuracy. How we calculate the league.