2005 Mercedes-Benz SLK — MOT failures & pass rate
30,137 MOT tests on the 2005 Mercedes-Benz SLK are in this dataset, and 76.7% of them passed. Against coupes & convertibles of a similar age (22.3% fail rate), the 2005 SLK comes out 1.1pp worse. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
Suspension dominates the failure mix at 14.0% of all tests — 6.1 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are coil spring, headlamp aim and ball joint — coil spring alone was recorded 1,991 times.
A 150k+ example is materially riskier than a 0-30k one: 31.0% versus 10.5%.
Advisories point at the next bill rather than this one: brakes was flagged on 28.1% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 14.0% | 4,231 |
| 2 | Lighting & signalling | 7.9% | 2,389 |
| 3 | Brakes | 6.2% | 1,873 |
| 4 | Tyres | 4.1% | 1,244 |
| 5 | Emissions & environmental | 3.6% | 1,086 |
| 6 | Visibility | 2.6% | 790 |
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 | 1,991 |
| 2 | Headlamp aim | 1,277 |
| 3 | Ball joint | 1,209 |
| 4 | Sub-frame | 1,105 |
| 5 | Rigid brake pipes | 874 |
| 6 | Headlamp | 848 |
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 | 28.1% | 8,466 |
| 2 | Tyres | 23.1% | 6,965 |
| 3 | Suspension | 22.7% | 6,848 |
| 4 | Lighting & signalling | 12.0% | 3,605 |
| 5 | Body, structure & corrosion | 8.6% | 2,586 |
| 6 | Other defects | 7.1% | 2,139 |
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 | 1,222 | 10.5% |
| 30-60k | 6,703 | 17.1% |
| 60-90k | 11,465 | 23.7% |
| 90-120k | 7,588 | 27.7% |
| 120-150k | 2,452 | 28.7% |
| 150k+ | 668 | 31.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 6,524 | 23.3% |
| 2022 | 6,277 | 22.7% |
| 2023 | 6,170 | 23.7% |
| 2024 | 5,806 | 23.7% |
| 2025 | 5,360 | 23.1% |
What to check before buying a 2005 SLK
On a 2005 SLK, suspension is what the MOT record says goes wrong most — it appeared in 14.0% of tests. Check these areas before you commit.
- Suspension (14.0% 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 (7.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (6.2% 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 SLKs pass their MOT?
76.7% of the 30,137 2005 Mercedes-Benz SLK MOT tests in this dataset passed — a 23.3% fail rate.
What is the most common MOT failure on a 2005 Mercedes-Benz SLK?
Suspension, recorded in 14.0% of tests, followed by lighting & signalling (7.9%).
Does the 2005 SLK get worse with mileage?
Its MOT fail rate rises from 10.5% in the 0-30k band to 31.0% in the 150k+ band.
Methodology & source. Based on 30,137 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.