2005 Mercedes-Benz Sl — MOT failures & pass rate
The 2005 Mercedes-Benz Sl passed 86.1% of its 6,634 recorded MOT tests. Coupes & convertibles of a similar age fail 22.3% of the time, so this is 8.3pp better than the group it competes with. Failures cluster in suspension, tyres and brakes.
What the MOT record shows
No single area dominates — suspension (6.5%) and tyres (3.7%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are coil spring, ball joint and headlamp aim — coil spring alone was recorded 221 times.
Mileage is the strongest signal on the record: 8.5% of 0-30k cars fail, rising to 25.2% once past 150k — 3.0× the risk.
Brakes is the most common advisory, noted on 23.3% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 6.5% | 431 |
| 2 | Tyres | 3.7% | 247 |
| 3 | Brakes | 3.6% | 236 |
| 4 | Lighting & signalling | 3.3% | 218 |
| 5 | Visibility | 2.1% | 136 |
| 6 | Emissions & environmental | 1.4% | 90 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Coil spring | 221 |
| 2 | Ball joint | 143 |
| 3 | Headlamp aim | 127 |
| 4 | Rigid brake pipes | 116 |
| 5 | Wipers | 94 |
| 6 | Tread depth | 82 |
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 | 23.3% | 1,545 |
| 2 | Tyres | 18.4% | 1,224 |
| 3 | Suspension | 14.2% | 945 |
| 4 | Emissions & environmental | 5.6% | 374 |
| 5 | Lighting & signalling | 5.4% | 359 |
| 6 | Other defects | 4.5% | 302 |
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 | 364 | 8.5% |
| 30-60k | 1,830 | 10.2% |
| 60-90k | 2,537 | 14.3% |
| 90-120k | 1,415 | 17.9% |
| 120-150k | 363 | 15.4% |
| 150k+ | 107 | 25.2% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,452 | 13.2% |
| 2022 | 1,391 | 15.1% |
| 2023 | 1,330 | 13.0% |
| 2024 | 1,260 | 14.4% |
| 2025 | 1,201 | 13.9% |
What to check before buying a 2005 Sl
The failure pattern for this year is specific enough to inspect against: suspension accounted for 6.5% of tests. Start there.
- Suspension (6.5% 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.
- Tyres (3.7% 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 (3.6% 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 2005 Mercedes-Benz Sls pass their MOT?
86.1% of the 6,634 2005 Mercedes-Benz Sl MOT tests in this dataset passed — a 13.9% fail rate.
What is the most common MOT failure on a 2005 Mercedes-Benz Sl?
Suspension, recorded in 6.5% of tests, followed by tyres (3.7%).
Does the 2005 Sl get worse with mileage?
Its MOT fail rate rises from 8.5% in the 0-30k band to 25.2% in the 150k+ band.
Methodology & source. Based on 6,634 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.