1983 Mercedes-Benz Sl — MOT failures & pass rate
The 1983 Mercedes-Benz Sl passed 85.9% of its 576 recorded MOT tests. That is effectively the same as coupes & convertibles of a similar age (14.9% fail rate), so the MOT record here is unremarkable in either direction. Failures cluster in lighting & signalling, brakes and visibility.
What the MOT record shows
No single area dominates — lighting & signalling (7.5%) and brakes (5.4%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, service brake performance and washers — headlamp aim alone was recorded 30 times.
Condition tracks the odometer closely. Failures run at 12.2% in the 30-60k band and 6.3% in the 150k+ band, a 6.0-point spread.
Brakes is the most common advisory, noted on 17.2% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 7.5% | 43 |
| 2 | Brakes | 5.4% | 31 |
| 3 | Visibility | 4.3% | 25 |
| 4 | Suspension | 4.2% | 24 |
| 5 | Body, structure & corrosion | 3.3% | 19 |
| 6 | Emissions & environmental | 1.4% | 8 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 30 |
| 2 | Service brake performance | 20 |
| 3 | Washers | 20 |
| 4 | Component mounting prescribed areas | 20 |
| 5 | Wipers | 16 |
| 6 | Position lamp | 12 |
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 | 17.2% | 99 |
| 2 | Suspension | 14.2% | 82 |
| 3 | Tyres | 12.3% | 71 |
| 4 | Emissions & environmental | 11.5% | 66 |
| 5 | Body, structure & corrosion | 8.0% | 46 |
| 6 | Steering | 4.3% | 25 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 30-60k | 90 | 12.2% |
| 60-90k | 142 | 15.5% |
| 90-120k | 198 | 14.6% |
| 120-150k | 73 | 16.4% |
| 150k+ | 48 | 6.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 157 | 14.6% |
| 2022 | 144 | 15.3% |
| 2023 | 137 | 14.6% |
| 2024 | 78 | 10.3% |
| 2025 | 60 | 13.3% |
What to check before buying a 1983 Sl
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 7.5% of tests. Start there.
- Lighting & signalling (7.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (5.4% 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.
- Visibility (4.3% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£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 1983 Mercedes-Benz Sls pass their MOT?
85.9% of the 576 1983 Mercedes-Benz Sl MOT tests in this dataset passed — a 14.1% fail rate.
What is the most common MOT failure on a 1983 Mercedes-Benz Sl?
Lighting & signalling, recorded in 7.5% of tests, followed by brakes (5.4%).
Does the 1983 Sl get worse with mileage?
Its MOT fail rate rises from 12.2% in the 30-60k band to 6.3% in the 150k+ band.
Methodology & source. Based on 576 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.