MOT fail rates by first-use year
2004 Mercedes-Benz SL MOT fail rate and common faults
How Mercedes-Benz SL cars first used in 2004 did at their MOTs from 2022 to 2025, against all cars of the same age. From 7,662 DVSA MOT tests of these cars. First use is usually the date the car was first registered.
MOT data updated
At 21 years, tested in 2025
What stands out
- In 2025, at 21 years old, Mercedes-Benz SL cars first used in 2004 failed 17.0% of MOTs (1,756 tests), 25.0 points below the 42.1% for all cars that age.
- From 2022 to 2025, as these cars went from 18 to 21 years old, the fail rate moved from 19.0% to 17.0%.
- Mercedes-Benz SL cars first used a year earlier, in 2003, failed 20.2% at the same age of 21 years (2,389 tests, in 2024).
- The most common fail item that is not a wear item, for the Mercedes-Benz SL at 21 years, is suspension ball joint worn, at 1.5 per 100 MOTs (all cars: 2.2).
MOT fail rate by test year
| Test year | Age | MOT fail rate | Tests (n) | All cars | Difference |
|---|---|---|---|---|---|
| 2022 | 18 years | 19.0% | 2,070 | 43.3% | −24.2 pts |
| 2023 | 19 years | 17.4% | 1,987 | 43.2% | −25.8 pts |
| 2024 | 20 years | 16.9% | 1,849 | 42.8% | −25.9 pts |
| 2025 | 21 years | 17.0% | 1,756 | 42.1% | −25.0 pts |
Most common faults at 21 years
These figures cover all Mercedes-Benz SL MOTs at 21 years: cars first used 2001 to 2004, tested 2022 to 2025 (n=5,503). The list uses every first-use year so it has enough tests. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.
MOT fail items
| Fail item | Per 100 MOTs | All cars |
|---|---|---|
| Suspension ball joint worn | 1.5 | 2.2 |
| Airbag (SRS) warning light on | 1.4 | 1.4 |
| Tyre with cords exposed Wear | 1.3 | 1.3 |
| Suspension arm ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt | 1.3 | 1.0 |
| Rigid brake pipes: excessively corroded | 1.3 | 2.5 |
| Wipers not clearing screen Wear | 1.2 | 3.5 |
| Shock absorber leaking | 1.0 | 1.1 |
| Dipped headlight not working Wear | 1.0 | 1.8 |
| Anti-lock braking system: warning lamp indicates an ABS fault | 0.9 | 1.2 |
| Coil spring broken | 0.9 | 2.3 |
Per 100 of the MOTs above (n=5,503). A test with two items counts once for each.
Advisories
| Advisory | Per 100 MOTs | All cars |
|---|---|---|
| Rigid brake pipes: corroded, covered in grease or other material | 10.7 | 15.9 |
| Tyre tread close to the legal limit or worn on the edge Wear | 9.8 | 14.8 |
| Tyre condition: slightly damaged/cracking or perishing Wear | 7.1 | 10.4 |
| Brake discs: worn, pitted or scored, but not seriously weakened | 6.7 | 10.4 |
| Engine oil leaks: leak, but not excessive | 5.0 | 14.8 |
| Suspension ball joint: slight play | 4.9 | 2.8 |
| Brake pads wearing thin Wear | 4.4 | 5.4 |
| Shock absorber misting oil | 3.8 | 3.2 |
| Suspension pin or bush worn, without excessive movement | 3.2 | 7.2 |
| Wheel bearings: has slight play | 2.9 | 1.8 |
Per 100 of the MOTs above (n=5,503). A test with two items counts once for each.
Fuel type at 21 years
These figures cover all Mercedes-Benz SL MOTs at 21 years: cars first used 2001 to 2004, tested 2022 to 2025 (n=5,503). Each fuel is set against all cars of the same fuel and age. Fuels with fewer than 1,000 tests are not shown.
| Fuel | Share of tests | MOT fail rate | Tests (n) | All cars, same fuel | Median mileage |
|---|---|---|---|---|---|
| Petrol | 100.0% | 18.9% | 5,490 | 41.7% | 73,891 miles |
Fail rate by mileage at 21 years
These figures cover all Mercedes-Benz SL MOTs at 21 years: cars first used 2001 to 2004, tested 2022 to 2025 (n=5,503). At 21 years, Mercedes-Benz SL cars at 90,000 to 120,000 miles failed more often (23.4%, n=1,162) than those at 30,000 to 60,000 miles (14.1%, n=1,426). Bands with fewer than 1,000 tests are not shown.
| Mileage at test | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|
| 30,000 to 60,000 miles | 14.1% | 1,426 | 33.5% |
| 60,000 to 90,000 miles | 20.0% | 2,028 | 40.6% |
| 90,000 to 120,000 miles | 23.4% | 1,162 | 44.7% |
Car tax rules for a 2004 car
- Cars first registered from 1 March 2001 to 31 March 2017 are taxed by CO2 emissions band, from band A (the lowest emissions) to band M. The band is set by the CO2 figure on the V5C logbook.
These are the rules, not the amount for a specific car. Car tax check
ULEZ and clean air zones
- Many petrol cars first registered from 2001 to 2005 already meet Euro 4, but not all of them. For a 2004 petrol car the Euro standard of that car decides.
- The clean air zones in Birmingham and Bristol use the same Euro 4 petrol and Euro 6 diesel standards. The low emission zones in Scotland use them too, but enforce them with fines, not a daily charge.
The Euro standard of the car decides, not the year alone. ULEZ checker
Other years of the Mercedes-Benz SL
Other Mercedes-Benz models first used in 2004
| Model | Age at test | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|---|
| Mercedes-Benz C-Class (2004) | 21 years in 2025 | 41.3% | 5,407 | 42.1% |
| Mercedes-Benz E-Class (2004) | 21 years in 2025 | 31.2% | 3,406 | 42.1% |
| Mercedes-Benz CLK (2004) | 21 years in 2025 | 36.6% | 3,466 | 42.1% |
| Mercedes-Benz SLK (2004) | 21 years in 2025 | 33.4% | 2,792 | 42.1% |
| Mercedes-Benz M-Class (2004) | 21 years in 2025 | 41.4% | 1,010 | 42.1% |
| Mercedes-Benz A-Class (2004) | 20 years in 2024 | 43.6% | 1,267 | 42.8% |
More on the Mercedes-Benz SL
Found one you might buy? Vet the specific car.
These figures describe 2004 Mercedes-Benz SL cars as a group, not any one car. The VetTheCar Buying Report looks at the car you are buying: its MOT history, what similar cars did next, and what to ask the seller.
Source
Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 28 September 2026.
Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources
Car tax and clean air zone rules are summarised from GOV.UK and Transport for London guidance. They are general rules and are not drawn from the MOT data.