Mercedes-Benz S350d — MOT pass rate & failures
The Mercedes-Benz S350d recorded a 93.3% MOT pass rate across 3,226 tests in this dataset (model years 2010–2025), with tyres, brakes and suspension its most common failure areas. Its 6.7% fail rate is lower than the 13.1% average across all Mercedes-Benz S-Class versions.
How it compares
By model year
| Year | Tests | Pass rate | Fail rate |
|---|---|---|---|
| 2010 | 31 | 90.3% | 9.7% |
| 2017 | 33 | 90.9% | 9.1% |
| 2019 | 353 | 93.5% | 6.5% |
| 2020 | 1,423 | 92.5% | 7.5% |
| 2021 | 978 | 94.5% | 5.5% |
| 2022 | 175 | 93.1% | 6.9% |
| 2023 | 88 | 94.3% | 5.7% |
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.5% | 144 |
| 2 | Brakes | 1.0% | 31 |
| 3 | Suspension | 0.7% | 23 |
| 4 | Visibility | 0.7% | 22 |
| 5 | Lighting & signalling | 0.7% | 22 |
| 6 | Emissions & environmental | 0.6% | 19 |
| 7 | Other defects | 0.4% | 12 |
| 8 | Road wheels | 0.3% | 11 |
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 | 52 |
| 2 | Brake pads | 29 |
| 3 | Ball joint | 26 |
| 4 | Headlamp aim | 21 |
| 5 | Registration plates | 21 |
| 6 | Malfunction indicator lamp | 17 |
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 | 16.5% | 533 |
| 2 | Brakes | 8.2% | 264 |
| 3 | Visibility | 2.5% | 82 |
| 4 | Suspension | 2.5% | 80 |
| 5 | Other defects | 1.9% | 63 |
| 6 | Road wheels | 0.7% | 22 |
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 | 1,066 | 5.5% |
| 30-60k | 1,238 | 7.8% |
| 60-90k | 530 | 6.4% |
| 90-120k | 234 | 5.1% |
| 120-150k | 100 | 10.0% |
| 150k+ | 57 | 8.8% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 68 | 7.3% |
| 2022 | 275 | 4.7% |
| 2023 | 721 | 6.8% |
| 2024 | 1,025 | 7.1% |
| 2025 | 1,137 | 6.8% |
What to check before buying a Mercedes-Benz S350d
Focus on the areas it most often fails on — and remember MOT data covers testable defects only, not engine or gearbox health.
- Tyres (4.5% 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.
- Brakes (1.0% 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.
- Suspension (0.7% 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.
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 S350d at MOT time?
93.3% of the 3,226 Mercedes-Benz S350d MOT tests in this dataset passed — a 6.7% fail rate, better than the 13.1% average across all S-Class versions.
What is the most common MOT failure on a Mercedes-Benz S350d?
Tyres, recorded in 4.5% of tests, followed by brakes (1.0%).
Does the S350d get worse with mileage?
Its MOT fail rate rises from 5.5% in the 0-30k band to 8.8% in the 150k+ band.
Methodology & source. Based on 3,226 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-06. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.