2013 Mercedes-Benz Sl — MOT failures & pass rate
6,343 MOT tests on the 2013 Mercedes-Benz Sl are in this dataset, and 87.1% of them passed. Coupes & convertibles of a similar age fail 14.7% of the time, so this is 1.9pp better than the group it competes with. Failures cluster in tyres, suspension and lighting & signalling.
What the MOT record shows
No single area dominates — tyres (5.0%) and suspension (3.2%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are malfunction indicator lamp, headlamp aim and ball joint — malfunction indicator lamp alone was recorded 156 times.
Condition tracks the odometer closely. Failures run at 8.5% in the 0-30k band and 28.0% in the 120-150k band, a 19.5-point spread — more than double.
Advisories point at the next bill rather than this one: tyres was flagged on 18.9% of tests without failing them.
The trend is worsening — 10.9% of tests failed in 2021 against 15.7% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.0% | 317 |
| 2 | Suspension | 3.2% | 201 |
| 3 | Lighting & signalling | 3.1% | 195 |
| 4 | Emissions & environmental | 3.0% | 190 |
| 5 | Brakes | 1.9% | 122 |
| 6 | Visibility | 1.2% | 78 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Malfunction indicator lamp | 156 |
| 2 | Headlamp aim | 93 |
| 3 | Ball joint | 89 |
| 4 | Rigid brake pipes | 88 |
| 5 | Registration plates | 86 |
| 6 | Position lamp | 63 |
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 | 18.9% | 1,202 |
| 2 | Brakes | 12.6% | 796 |
| 3 | Suspension | 5.4% | 341 |
| 4 | Other defects | 3.1% | 198 |
| 5 | Visibility | 2.7% | 170 |
| 6 | Lighting & signalling | 2.4% | 151 |
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 | 1,583 | 8.5% |
| 30-60k | 3,358 | 12.9% |
| 60-90k | 1,139 | 16.8% |
| 90-120k | 199 | 19.6% |
| 120-150k | 50 | 28.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,267 | 10.9% |
| 2022 | 1,249 | 11.6% |
| 2023 | 1,275 | 12.2% |
| 2024 | 1,255 | 13.9% |
| 2025 | 1,297 | 15.7% |
What to check before buying a 2013 Sl
On a 2013 Sl, tyres is what the MOT record says goes wrong most — it appeared in 5.0% of tests. Check these areas before you commit.
- Tyres (5.0% 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 (3.2% 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 (3.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
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 2013 Mercedes-Benz Sls pass their MOT?
87.1% of the 6,343 2013 Mercedes-Benz Sl MOT tests in this dataset passed — a 12.9% fail rate.
What is the most common MOT failure on a 2013 Mercedes-Benz Sl?
Tyres, recorded in 5.0% of tests, followed by suspension (3.2%).
Does the 2013 Sl get worse with mileage?
Its MOT fail rate rises from 8.5% in the 0-30k band to 28.0% in the 120-150k band.
Methodology & source. Based on 6,343 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.