1997 Mercedes-Benz S-Class — MOT failures & pass rate
The 1997 Mercedes-Benz S-Class passed 82.5% of its 770 recorded MOT tests. That is 4.7 percentage points better than executive cars of a similar age, which fail at 22.2%. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
No single area dominates — lighting & signalling (11.6%) and suspension (8.7%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are wipers, catalyst emissions and stop lamp — wipers alone was recorded 41 times.
Mileage matters less than usual here: the 1997 S-Class fails 19.2% of the time in the 30-60k band and 19.8% at 150k+, a spread of only 0.5 points.
Brakes is the most common advisory, noted on 31.2% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 23.5% in 2021 to 16.3% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.6% | 89 |
| 2 | Suspension | 8.7% | 67 |
| 3 | Brakes | 6.9% | 53 |
| 4 | Visibility | 6.2% | 48 |
| 5 | Emissions & environmental | 4.0% | 31 |
| 6 | Tyres | 3.5% | 27 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Wipers | 41 |
| 2 | Catalyst emissions | 35 |
| 3 | Stop lamp | 33 |
| 4 | Headlamp aim | 28 |
| 5 | Individual direction indicators | 26 |
| 6 | Side repeaters | 24 |
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 | 31.2% | 240 |
| 2 | Suspension | 29.6% | 228 |
| 3 | Emissions & environmental | 27.5% | 212 |
| 4 | Tyres | 19.7% | 152 |
| 5 | Other defects | 11.9% | 92 |
| 6 | Visibility | 8.7% | 67 |
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 | 52 | 19.2% |
| 60-90k | 195 | 16.4% |
| 90-120k | 215 | 17.2% |
| 120-150k | 130 | 17.7% |
| 150k+ | 157 | 19.8% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 196 | 23.5% |
| 2022 | 178 | 18.5% |
| 2023 | 152 | 13.2% |
| 2024 | 121 | 13.2% |
| 2025 | 123 | 16.3% |
What to check before buying a 1997 S-Class
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 11.6% of tests. Start there.
- Lighting & signalling (11.6% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (8.7% 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 (6.9% 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 1997 Mercedes-Benz S-Classs pass their MOT?
82.5% of the 770 1997 Mercedes-Benz S-Class MOT tests in this dataset passed — a 17.5% fail rate.
What is the most common MOT failure on a 1997 Mercedes-Benz S-Class?
Lighting & signalling, recorded in 11.6% of tests, followed by suspension (8.7%).
Does the 1997 S-Class get worse with mileage?
Its MOT fail rate rises from 19.2% in the 30-60k band to 19.8% in the 150k+ band.
Methodology & source. Based on 770 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.