2008 Mercedes-Benz Sl — MOT failures & pass rate
4,453 MOT tests on the 2008 Mercedes-Benz Sl are in this dataset, and 86.4% of them passed. Coupes & convertibles of a similar age fail 21.1% of the time, so this is 7.5pp better than the group it competes with. Failures cluster in suspension, tyres and lighting & signalling.
What the MOT record shows
No single area dominates — suspension (5.4%) and tyres (4.6%) 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 119 times.
A 120-150k example is materially riskier than a 0-30k one: 19.2% versus 7.5%.
Advisories point at the next bill rather than this one: brakes was flagged on 22.8% of tests without failing them.
The trend is improving — the fail rate fell from 14.4% in 2021 to 12.9% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 5.4% | 241 |
| 2 | Tyres | 4.6% | 203 |
| 3 | Lighting & signalling | 3.5% | 156 |
| 4 | Brakes | 3.4% | 149 |
| 5 | Visibility | 1.7% | 77 |
| 6 | Emissions & environmental | 1.0% | 44 |
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 | 119 |
| 2 | Ball joint | 98 |
| 3 | Headlamp aim | 65 |
| 4 | Rigid brake pipes | 65 |
| 5 | Wipers | 52 |
| 6 | Shock absorbers | 47 |
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 | 22.8% | 1,014 |
| 2 | Tyres | 17.7% | 788 |
| 3 | Suspension | 12.8% | 572 |
| 4 | Other defects | 4.2% | 187 |
| 5 | Lighting & signalling | 4.2% | 186 |
| 6 | Visibility | 3.3% | 147 |
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 | 453 | 7.5% |
| 30-60k | 1,736 | 11.6% |
| 60-90k | 1,500 | 15.3% |
| 90-120k | 621 | 18.4% |
| 120-150k | 125 | 19.2% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 957 | 14.4% |
| 2022 | 917 | 13.4% |
| 2023 | 889 | 13.6% |
| 2024 | 859 | 13.5% |
| 2025 | 831 | 12.9% |
What to check before buying a 2008 Sl
On a 2008 Sl, suspension is what the MOT record says goes wrong most — it appeared in 5.4% of tests. Check these areas before you commit.
- Suspension (5.4% 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.
- Tyres (4.6% 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.
- Lighting & signalling (3.5% 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 Sls pass their MOT?
86.4% of the 4,453 2008 Mercedes-Benz Sl MOT tests in this dataset passed — a 13.6% fail rate.
What is the most common MOT failure on a 2008 Mercedes-Benz Sl?
Suspension, recorded in 5.4% of tests, followed by tyres (4.6%).
Does the 2008 Sl get worse with mileage?
Its MOT fail rate rises from 7.5% in the 0-30k band to 19.2% in the 120-150k band.
Methodology & source. Based on 4,453 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.