3,258 tests in 2025
Mercedes-Benz Gl reliability and MOT pass rate
85.4% passed first time. The 14.6% fail rate is 8.0 points better than the all-car average, on a median example 12 years old with 103,582 miles.
MOT pass rates / Mercedes-Benz
Pass rate
85.4%
22.6% of all cars failed; 14.6% of these did.
Fixed on the day
3.6%
Passed after a defect was put right during the visit.
Median at test
103,582 mi
12 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 66 | — |
| 6-9 years | 305 | 15.1% |
| 10-13 years | 1,647 | 12.8% |
| 14+ years | 1,240 | 17.4% |
What the Gl fails on
Share of failed tests with at least one fail item in each DVSA inspection section. A test can fail in several sections at once.
- Tyres196 dangerous35%
- Brakes58 dangerous27.5%
- Lamps, reflectors and electrical equipment1 dangerous20.5%
- Noise, emissions and leaks3 dangerous18%
- Suspension10 dangerous17.8%
- Body, chassis, structure1 dangerous13.6%
- Visibility9.2%
- Seat belts and supplementary restraint systems6.7%
Is the Gl getting worse?
The fail rate fell 2.3 points to 13.8% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 7.4 points, so it is holding up better than the fleet average for its age.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 3,421 | 9 | 16.1% | 22.5% | |
| 2023 | 3,307 | 10 | 16.2% | 22.8% | |
| 2024 | 2,882 | 11 | 15.4% | 23.2% | |
| 2025 | 2,917 | 12 | 13.8% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical Gl at its test that year, and it is the number to watch: across the whole fleet each extra year of age adds roughly 1.9 points to the fail rate, so a model whose age and fail rate rise together is simply getting older.
The exact defects that fail it
Every failure item DVSA recorded against a Gl in 2025, counted by how many tests each one appeared on.
- 1Tread depth: tread depth below requirements of 1.6mm72 tests
- 2Malfunction indicator lamp: inoperative or indicates a malfunction51 tests
- 3Condition: has ply or cords exposed50 tests
- 4Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt44 tests
- 5Rigid brake pipes: excessively corroded41 tests
- 6Condition: has a cut in excess of the requirements deep enough to reach the ply or cords39 tests
- 7Shock absorbers: has a serious fluid leak29 tests
- 8Position lamp: not working27 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical Gl collects 2.6 of them per test, and these are the ones that come up most. Treat it as the running-repairs list for the next year or two.
- 1Tread depth: tread depth below requirements of 1.6mm573 tests
- 2Engine oil leaks: leaking excessively from engine407 tests
- 3Brake discs: in such a condition that it is seriously weakened252 tests
- 4Rigid brake pipes: excessively corroded231 tests
- 5Brake pads: less than 1.5 mm thick206 tests
- 6Shock absorbers: has a serious fluid leak136 tests
- 7Brake discs: significantly and obviously worn122 tests
- 8Pins and bushes: pin or bush excessively worn119 tests
Questions
What is the Mercedes-Benz Gl MOT pass rate?
85.4% of the 3,258 Mercedes-Benz Gl first-attempt MOTs in 2025 passed. The fail rate of 14.6% compares with 22.6% across all cars. A further 3.6% passed after a defect was fixed during the test visit.
What does a Mercedes-Benz Gl usually fail on?
The single most common failure is "Tread depth: tread depth below requirements of 1.6mm", recorded on 72 failed tests, followed by "Malfunction indicator lamp: inoperative or indicates a malfunction" and "Condition: has ply or cords exposed". By section, tyres appears in 35% of failures, brakes appears in 27.5% of failures, lamps, reflectors and electrical equipment appears in 20.5% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was 7.6%; at 14+ years it was 17.4%. The median Mercedes-Benz Gl tested in 2025 was 12 years old with 103,582 miles.
Is the Mercedes-Benz Gl getting less reliable?
The fail rate fell 2.3 points to 13.8% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 7.4 points, so it is holding up better than the fleet average for its age.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (OGL v3, retrieved 2026-09-12). DVSA records newer cars trim by trim; this page adds every Gl trim together. Year-on-year figures come from the same DVSA extracts for 2026 and earlier years. Full method on the pass rates hub.
DVSA has published 16 safety recalls naming the Mercedes-Benz Gl: Mercedes-Benz Gl recalls.
Other Mercedes-Benz models
Checking a particular Gl?
The odds above are the model. The car in front of you has its own record: every test, every advisory, the mileage at each one.
Due a test? Find an approved MOT station near you.