2017 Mercedes-Benz GLC — MOT failures & pass rate
The 2017 Mercedes-Benz GLC passed 89.5% of its 70,860 recorded MOT tests. Against mid-size SUVs of a similar age (11.8% fail rate), the 2017 GLC comes out 1.3pp better. Failures cluster in tyres, suspension and brakes.
What the MOT record shows
No single area dominates — tyres (4.4%) and suspension (3.9%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are ball joint, tread depth and brake pads — ball joint alone was recorded 2,842 times.
Mileage is the strongest signal on the record: 6.7% of 0-30k cars fail, rising to 15.3% once past 150k — 2.3× the risk.
Fuel type barely separates them — petrol fails 9.2% of the time against 10.6% for diesel.
Tyres is the most common advisory, noted on 21.9% of tests — work that passed today but is likely due soon.
The trend is worsening — 8.4% of tests failed in 2021 against 12.4% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.4% | 3,107 |
| 2 | Suspension | 3.9% | 2,751 |
| 3 | Brakes | 1.6% | 1,104 |
| 4 | Emissions & environmental | 1.4% | 975 |
| 5 | Visibility | 1.3% | 893 |
| 6 | Lighting & signalling | 1.1% | 815 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 2,842 |
| 2 | Tread depth | 1,678 |
| 3 | Brake pads | 1,090 |
| 4 | Malfunction indicator lamp | 956 |
| 5 | Headlamp aim | 794 |
| 6 | Washers | 614 |
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 | 21.9% | 15,495 |
| 2 | Brakes | 12.9% | 9,125 |
| 3 | Suspension | 7.8% | 5,496 |
| 4 | Other defects | 6.4% | 4,541 |
| 5 | Visibility | 3.0% | 2,114 |
| 6 | Lighting & signalling | 0.6% | 439 |
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 | 10,777 | 6.7% |
| 30-60k | 36,029 | 10.2% |
| 60-90k | 18,778 | 12.4% |
| 90-120k | 4,301 | 13.8% |
| 120-150k | 790 | 15.7% |
| 150k+ | 170 | 15.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 67,629 | 10.6% |
| Petrol | 3,231 | 9.2% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 14,331 | 8.4% |
| 2022 | 14,122 | 9.2% |
| 2023 | 14,176 | 10.6% |
| 2024 | 14,217 | 12.0% |
| 2025 | 14,014 | 12.4% |
What to check before buying a 2017 GLC
The failure pattern for this year is specific enough to inspect against: tyres accounted for 4.4% of tests. Start there.
- Tyres (4.4% 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.
- Suspension (3.9% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Brakes (1.6% 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
How many 2017 Mercedes-Benz GLCs pass their MOT?
89.5% of the 70,860 2017 Mercedes-Benz GLC MOT tests in this dataset passed — a 10.5% fail rate.
What is the most common MOT failure on a 2017 Mercedes-Benz GLC?
Tyres, recorded in 4.4% of tests, followed by suspension (3.9%).
Does the 2017 GLC get worse with mileage?
Its MOT fail rate rises from 6.7% in the 0-30k band to 15.3% in the 150k+ band.
Methodology & source. Based on 70,860 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.