1993 Mercedes-Benz Sl — MOT failures & pass rate
940 MOT tests on the 1993 Mercedes-Benz Sl are in this dataset, and 86.4% of them passed. That is 5.7 percentage points better than coupes & convertibles of a similar age, which fail at 19.3%. Failures cluster in lighting & signalling, brakes and emissions & environmental.
What the MOT record shows
Lighting & signalling dominates the failure mix at 11.2% of all tests — 7.0 points clear of brakes, so it is the first thing to check.
At component level the recurring items are catalyst emissions, position lamp and wipers — catalyst emissions alone was recorded 43 times.
Condition tracks the odometer closely. Failures run at 1.9% in the 0-30k band and 15.4% in the 150k+ band, a 13.5-point spread — more than double.
Advisories point at the next bill rather than this one: brakes was flagged on 22.2% of tests without failing them.
The trend is worsening — 11.7% of tests failed in 2021 against 16.9% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.2% | 105 |
| 2 | Brakes | 4.2% | 39 |
| 3 | Emissions & environmental | 4.0% | 38 |
| 4 | Visibility | 3.8% | 36 |
| 5 | Suspension | 2.7% | 25 |
| 6 | Tyres | 2.1% | 20 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Catalyst emissions | 43 |
| 2 | Position lamp | 42 |
| 3 | Wipers | 27 |
| 4 | Headlamp aim | 26 |
| 5 | Side repeaters | 21 |
| 6 | Individual direction indicators | 20 |
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 | 22.2% | 209 |
| 2 | Suspension | 18.9% | 178 |
| 3 | Tyres | 15.1% | 142 |
| 4 | Emissions & environmental | 14.3% | 134 |
| 5 | Other defects | 5.6% | 53 |
| 6 | Steering | 5.5% | 52 |
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 | 53 | 1.9% |
| 30-60k | 138 | 10.1% |
| 60-90k | 284 | 14.1% |
| 90-120k | 287 | 15.3% |
| 120-150k | 125 | 16.8% |
| 150k+ | 52 | 15.4% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 188 | 11.7% |
| 2022 | 227 | 14.1% |
| 2023 | 184 | 15.2% |
| 2024 | 169 | 10.1% |
| 2025 | 172 | 16.9% |
What to check before buying a 1993 Sl
On a 1993 Sl, lighting & signalling is what the MOT record says goes wrong most — it appeared in 11.2% of tests. Check these areas before you commit.
- Lighting & signalling (11.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (4.2% 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.
- Emissions & environmental (4.0% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 1993 Mercedes-Benz Sls pass their MOT?
86.4% of the 940 1993 Mercedes-Benz Sl MOT tests in this dataset passed — a 13.6% fail rate.
What is the most common MOT failure on a 1993 Mercedes-Benz Sl?
Lighting & signalling, recorded in 11.2% of tests, followed by brakes (4.2%).
Does the 1993 Sl get worse with mileage?
Its MOT fail rate rises from 1.9% in the 0-30k band to 15.4% in the 150k+ band.
Methodology & source. Based on 940 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.