2011 Mercedes-Benz SLK — MOT failures & pass rate
Across 15,074 MOT tests, the 2011 Mercedes-Benz SLK recorded an 82.9% pass rate. That is effectively the same as coupes & convertibles of a similar age (17.8% fail rate), so the MOT record here is unremarkable in either direction. Failures cluster in suspension, tyres and brakes.
What the MOT record shows
One area stands out: suspension, recorded in 8.6% of tests against 5.1% for the next-worst category.
At component level the recurring items are coil spring, rigid brake pipes and tread depth — coil spring alone was recorded 729 times.
Condition tracks the odometer closely. Failures run at 9.0% in the 0-30k band and 27.9% in the 150k+ band, a 18.9-point spread — more than double.
Brakes is the most common advisory, noted on 24.0% of tests — work that passed today but is likely due soon.
The trend is worsening — 16.3% of tests failed in 2021 against 18.7% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 8.6% | 1,294 |
| 2 | Tyres | 5.1% | 774 |
| 3 | Brakes | 4.3% | 645 |
| 4 | Lighting & signalling | 3.9% | 587 |
| 5 | Visibility | 1.4% | 213 |
| 6 | Emissions & environmental | 1.0% | 148 |
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 | 729 |
| 2 | Rigid brake pipes | 470 |
| 3 | Tread depth | 400 |
| 4 | Ball joint dust cover | 298 |
| 5 | Ball joint | 288 |
| 6 | Headlamp aim | 275 |
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 | 24.0% | 3,621 |
| 2 | Tyres | 23.4% | 3,527 |
| 3 | Suspension | 14.7% | 2,212 |
| 4 | Other defects | 3.5% | 529 |
| 5 | Emissions & environmental | 3.1% | 463 |
| 6 | Visibility | 2.9% | 442 |
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 | 1,651 | 9.0% |
| 30-60k | 7,117 | 15.1% |
| 60-90k | 4,791 | 20.5% |
| 90-120k | 1,280 | 24.6% |
| 120-150k | 192 | 25.0% |
| 150k+ | 43 | 27.9% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 14,990 | 17.1% |
| Diesel | 79 | 19.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 3,066 | 16.3% |
| 2022 | 2,993 | 15.6% |
| 2023 | 3,036 | 17.2% |
| 2024 | 2,980 | 17.8% |
| 2025 | 2,999 | 18.7% |
What to check before buying a 2011 SLK
The failure pattern for this year is specific enough to inspect against: suspension accounted for 8.6% of tests. Start there.
- Suspension (8.6% 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 (5.1% 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 (4.3% 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 2011 Mercedes-Benz SLKs pass their MOT?
82.9% of the 15,074 2011 Mercedes-Benz SLK MOT tests in this dataset passed — a 17.1% fail rate.
What is the most common MOT failure on a 2011 Mercedes-Benz SLK?
Suspension, recorded in 8.6% of tests, followed by tyres (5.1%).
Does the 2011 SLK get worse with mileage?
Its MOT fail rate rises from 9.0% in the 0-30k band to 27.9% in the 150k+ band.
Methodology & source. Based on 15,074 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.