2008 Mercedes-Benz Gl 320 — MOT failures & pass rate
The 2008 Mercedes-Benz Gl 320 passed 78.4% of its 426 recorded MOT tests. Against all cars of a similar age (26.1% fail rate), the 2008 Gl 320 comes out 4.5pp better. Failures cluster in lighting & signalling, brakes and emissions & environmental.
What the MOT record shows
Lighting & signalling dominates the failure mix at 12.9% of all tests — 4.0 points clear of brakes, so it is the first thing to check.
At component level the recurring items are rigid brake pipes, position lamp and individual direction indicators — rigid brake pipes alone was recorded 25 times.
Mileage matters less than usual here: the 2008 Gl 320 fails 23.3% of the time in the 60-90k band and 21.6% at 150k+, a spread of only 1.8 points.
Advisories point at the next bill rather than this one: brakes was flagged on 40.8% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 12.9% | 55 |
| 2 | Brakes | 8.9% | 38 |
| 3 | Emissions & environmental | 4.9% | 21 |
| 4 | Suspension | 4.7% | 20 |
| 5 | Tyres | 4.7% | 20 |
| 6 | Seat belts & restraints | 2.8% | 12 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rigid brake pipes | 25 |
| 2 | Position lamp | 21 |
| 3 | Individual direction indicators | 16 |
| 4 | Headlamp | 14 |
| 5 | Tread depth | 13 |
| 6 | Shock absorbers | 13 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 40.8% | 174 |
| 2 | Tyres | 31.2% | 133 |
| 3 | Emissions & environmental | 27.0% | 115 |
| 4 | Suspension | 21.6% | 92 |
| 5 | Lighting & signalling | 11.3% | 48 |
| 6 | Other defects | 8.2% | 35 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 60-90k | 60 | 23.3% |
| 90-120k | 111 | 19.8% |
| 120-150k | 143 | 23.1% |
| 150k+ | 102 | 21.6% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 105 | 20.9% |
| 2022 | 96 | 20.8% |
| 2023 | 94 | 20.2% |
| 2024 | 71 | 26.8% |
| 2025 | 60 | 20.0% |
What to check before buying a 2008 Gl 320
On a 2008 Gl 320, lighting & signalling is what the MOT record says goes wrong most — it appeared in 12.9% of tests. Check these areas before you commit.
- Lighting & signalling (12.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.9% 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.
- Emissions & environmental (4.9% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2008 Mercedes-Benz Gl 320s pass their MOT?
78.4% of the 426 2008 Mercedes-Benz Gl 320 MOT tests in this dataset passed — a 21.6% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz Gl 320?
Lighting & signalling, recorded in 12.9% of tests, followed by brakes (8.9%).
Does the 2008 Gl 320 get worse with mileage?
Its MOT fail rate rises from 23.3% in the 60-90k band to 21.6% in the 150k+ band.
Methodology & source. Based on 426 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.