Mercedes-Benz Gl MOT pass rate & common failures
The Mercedes-Benz Gl appears in 18,669 MOT tests spanning model years 1990–2022, and 86.3% of them passed. Large SUVs of a similar age fail 17.2% of the time, so this is 3.5pp better than the group it competes with. Its most common failure areas are tyres, lighting & signalling and brakes.
Best and worst Gl years
Ranked across Gl years with at least 1,000 tests. Older cars fail more simply because they are older — compare years close together in age before drawing conclusions.
What the MOT record shows
Build year matters more than the headline suggests: 2015 cars pass 88.5% of the time while 2007 cars manage 81.8%, a 6.6-point spread.
No single area dominates — tyres (5.3%) and lighting & signalling (5.3%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, headlamp aim and rigid brake pipes — tread depth alone was recorded 660 times.
Condition tracks the odometer closely. Failures run at 8.1% in the 0-30k band and 16.7% in the 150k+ band, a 8.5-point spread — more than double.
Split by fuel, diesel examples fail 3.0pp more often than petrol ones (14.1% vs 11.0%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: tyres was flagged on 22.3% of tests without failing them.
How it compares
By model year
Every Gl model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 2006 | 448 | 83.3% | 16.7% | Brakes |
| 2007 | 1,639 | 81.8% | 18.2% | Lighting & signalling |
| 2008 | 1,201 | 83.4% | 16.7% | Lighting & signalling |
| 2009 | 630 | 82.5% | 17.5% | Lighting & signalling |
| 2010 | 1,163 | 84.3% | 15.7% | Lighting & signalling |
| 2011 | 1,653 | 84.5% | 15.6% | Brakes |
| 2012 | 572 | 87.1% | 12.9% | Lighting & signalling |
| 2013 | 2,859 | 87.8% | 12.2% | Tyres |
| 2014 | 3,026 | 87.8% | 12.2% | Tyres |
| 2015 | 3,579 | 88.5% | 11.5% | Tyres |
| 2016 | 1,259 | 87.3% | 12.7% | Tyres |
| 2017 | 84 | 88.1% | 11.9% | Tyres |
| 2018 | 124 | 89.5% | 10.5% | Lighting & signalling |
| 2019 | 216 | 87.5% | 12.5% | Tyres |
| 2020 | 85 | 91.8% | 8.2% | Suspension |
| 2021 | 58 | 93.1% | 6.9% | Other defects |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.3% | 998 |
| 2 | Lighting & signalling | 5.3% | 994 |
| 3 | Brakes | 3.8% | 700 |
| 4 | Emissions & environmental | 2.3% | 425 |
| 5 | Suspension | 2.0% | 378 |
| 6 | Body, structure & corrosion | 1.5% | 285 |
| 7 | Visibility | 1.5% | 279 |
| 8 | Seat belts & restraints | 0.9% | 169 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 660 |
| 2 | Headlamp aim | 387 |
| 3 | Rigid brake pipes | 346 |
| 4 | Malfunction indicator lamp | 323 |
| 5 | Position lamp | 245 |
| 6 | Joints | 220 |
| 7 | Brake pads | 215 |
| 8 | Shock absorbers | 212 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 22.3% | 4,160 |
| 2 | Brakes | 20.5% | 3,831 |
| 3 | Emissions & environmental | 9.1% | 1,702 |
| 4 | Suspension | 8.8% | 1,641 |
| 5 | Other defects | 7.1% | 1,326 |
| 6 | Body, structure & corrosion | 5.2% | 972 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 676 | 8.1% |
| 30-60k | 3,328 | 11.2% |
| 60-90k | 5,322 | 12.7% |
| 90-120k | 4,847 | 14.4% |
| 120-150k | 2,847 | 17.0% |
| 150k+ | 1,646 | 16.7% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 16,581 | 14.1% |
| Petrol | 2,085 | 11.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 3,943 | 13.9% |
| 2022 | 3,889 | 14.2% |
| 2023 | 3,765 | 14.2% |
| 2024 | 3,623 | 13.8% |
| 2025 | 3,449 | 12.5% |
What to check before buying a Mercedes-Benz Gl
- Tyres (5.3% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Lighting & signalling (5.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (3.8% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
What is the MOT pass rate for the Mercedes-Benz Gl?
86.3% of the 18,669 Mercedes-Benz Gl MOT tests in this dataset passed, a 13.7% fail rate, across model years 1990–2022.
What does the Mercedes-Benz Gl most often fail its MOT on?
Tyres, recorded in 5.3% of tests, then lighting & signalling (5.3%).
Which Gl years are best and worst for MOT results?
2015 has the best pass rate at 88.5% and 2007 the weakest at 81.8%, from 3,579 and 1,639 tests respectively.
How much does mileage affect Gl MOT results?
Fail rates run at 8.1% for cars in the 0-30k band and 16.7% for 150k+, a 8.5-point difference.
Is the petrol or diesel Gl more reliable at MOT time?
On MOT-testable defects the petrol fails 11.0% of the time against 14.1% for the diesel. This covers testable items only, not engine or gearbox reliability.
Methodology & source. Based on 18,669 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.