Mercedes-Benz C320 — MOT pass rate & failures
3,623 MOT tests on the Mercedes-Benz C320 (1999–2016) give a 74.1% pass rate. That is 7.9 percentage points worse than the 17.9% fail rate across all Mercedes-Benz C-Class versions, so the C320 is a weaker pick within the range. Failures concentrate in suspension, lighting & signalling and brakes.
What the MOT record shows
At component level the recurring items are ball joint, coil spring and headlamp aim — ball joint alone was recorded 271 times.
A 150k+ example is materially riskier than a 0-30k one: 29.0% versus 8.8%.
Suspension is the most common advisory, noted on 35.3% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 26.7% in 2021 to 24.0% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
| Year | Tests | Pass rate | Fail rate |
|---|---|---|---|
| 2000 | 174 | 75.9% | 24.1% |
| 2001 | 835 | 74.9% | 25.1% |
| 2002 | 664 | 74.9% | 25.1% |
| 2003 | 891 | 74.5% | 25.5% |
| 2004 | 742 | 72.5% | 27.5% |
| 2005 | 263 | 72.2% | 27.8% |
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 16.1% | 582 |
| 2 | Lighting & signalling | 11.7% | 425 |
| 3 | Brakes | 7.8% | 281 |
| 4 | Visibility | 5.7% | 208 |
| 5 | Tyres | 5.6% | 203 |
| 6 | Body, structure & corrosion | 2.7% | 99 |
| 7 | Steering | 2.4% | 85 |
| 8 | Seat belts & restraints | 2.2% | 79 |
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 | 271 |
| 2 | Coil spring | 257 |
| 3 | Headlamp aim | 217 |
| 4 | Pins and bushes | 129 |
| 5 | Wipers | 127 |
| 6 | Headlamp | 124 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 35.3% | 1,280 |
| 2 | Brakes | 33.1% | 1,201 |
| 3 | Tyres | 25.2% | 912 |
| 4 | Other defects | 14.4% | 521 |
| 5 | Emissions & environmental | 14.3% | 519 |
| 6 | Lighting & signalling | 14.3% | 519 |
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 | 68 | 8.8% |
| 30-60k | 426 | 19.7% |
| 60-90k | 970 | 27.3% |
| 90-120k | 1,081 | 25.6% |
| 120-150k | 637 | 27.9% |
| 150k+ | 428 | 29.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,027 | 26.7% |
| 2022 | 874 | 27.1% |
| 2023 | 715 | 25.4% |
| 2024 | 566 | 24.4% |
| 2025 | 441 | 24.0% |
What to check before buying a Mercedes-Benz C320
Focus on the areas it most often fails on — and remember MOT data covers testable defects only, not engine or gearbox health.
- Suspension (16.1% 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.
- Lighting & signalling (11.7% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (7.8% 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
How reliable is the Mercedes-Benz C320 at MOT time?
74.1% of the 3,623 Mercedes-Benz C320 MOT tests in this dataset passed — a 25.9% fail rate, worse than the 17.9% average across all C-Class versions.
What is the most common MOT failure on a Mercedes-Benz C320?
Suspension, recorded in 16.1% of tests, followed by lighting & signalling (11.7%).
Does the C320 get worse with mileage?
Its MOT fail rate rises from 8.8% in the 0-30k band to 29.0% in the 150k+ band.
Methodology & source. Based on 3,623 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.