2008 Mercedes-Benz SLK — MOT failures & pass rate
The 2008 Mercedes-Benz SLK passed 77.7% of its 20,039 recorded MOT tests. Against coupes & convertibles of a similar age (21.1% fail rate), the 2008 SLK comes out 1.3pp worse. Failures cluster in suspension, brakes and lighting & signalling.
What the MOT record shows
One area stands out: suspension, recorded in 13.4% of tests against 6.5% for the next-worst category.
At component level the recurring items are coil spring, ball joint and rigid brake pipes — coil spring alone was recorded 1,465 times.
A 150k+ example is materially riskier than a 0-30k one: 26.2% versus 12.2%.
Brakes is the most common advisory, noted on 28.0% of tests — work that passed today but is likely due soon.
The trend is worsening — 21.5% of tests failed in 2021 against 23.3% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 13.4% | 2,675 |
| 2 | Brakes | 6.5% | 1,297 |
| 3 | Lighting & signalling | 5.8% | 1,158 |
| 4 | Tyres | 4.3% | 859 |
| 5 | Visibility | 2.3% | 459 |
| 6 | Emissions & environmental | 1.7% | 337 |
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 | 1,465 |
| 2 | Ball joint | 1,093 |
| 3 | Rigid brake pipes | 785 |
| 4 | Tread depth | 494 |
| 5 | Rbt (sp) | 425 |
| 6 | Headlamp aim | 383 |
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 | 28.0% | 5,611 |
| 2 | Tyres | 23.1% | 4,627 |
| 3 | Suspension | 21.3% | 4,260 |
| 4 | Lighting & signalling | 6.9% | 1,380 |
| 5 | Body, structure & corrosion | 6.2% | 1,245 |
| 6 | Other defects | 5.9% | 1,188 |
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 | 930 | 12.2% |
| 30-60k | 6,053 | 18.0% |
| 60-90k | 8,139 | 23.9% |
| 90-120k | 3,704 | 26.7% |
| 120-150k | 920 | 27.7% |
| 150k+ | 282 | 26.2% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 4,109 | 21.5% |
| 2022 | 4,056 | 21.4% |
| 2023 | 4,075 | 22.6% |
| 2024 | 3,928 | 22.9% |
| 2025 | 3,871 | 23.3% |
What to check before buying a 2008 SLK
The failure pattern for this year is specific enough to inspect against: suspension accounted for 13.4% of tests. Start there.
- Suspension (13.4% 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.
- Brakes (6.5% 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.
- Lighting & signalling (5.8% 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 2008 Mercedes-Benz SLKs pass their MOT?
77.7% of the 20,039 2008 Mercedes-Benz SLK MOT tests in this dataset passed — a 22.3% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz SLK?
Suspension, recorded in 13.4% of tests, followed by brakes (6.5%).
Does the 2008 SLK get worse with mileage?
Its MOT fail rate rises from 12.2% in the 0-30k band to 26.2% in the 150k+ band.
Methodology & source. Based on 20,039 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.