Does the Mercedes-Benz 300 fail the MOT on noise, emissions and leaks more than it should?
The Mercedes-Benz 300 records 4.10 noise, emissions and leaks failure items per 100 initial MOT tests (2019–2024), against 7.31 expected for a car of the same age mix: less than expected for its class and age (−3.21, 95% interval −3.61 to −2.82). It ranks 617 of 678 models on noise, emissions and leaks (1 = most failures above expected).
Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · all models on noise, emissions and leaks · check a Mercedes-Benz 300 by registration
What exactly fails on noise, emissions and leaks?
The most frequent DVSA defect wording in this group on the Mercedes-Benz 300 is “Emissions levels exceed default limits”, recorded 383 times in 2019–2024.
| DVSA defect wording | Items | Per 100 tests |
|---|---|---|
| Emissions levels exceed default limits | 383 | 2.11 |
| Emissions test unable to be completed | 85 | 0.47 |
| Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users | 77 | 0.42 |
| Emissions levels exceed the manufacturer's specified limits | 44 | 0.24 |
| Lambda coefficient outside the default limits or the range specified by the manufacturer | 42 | 0.23 |
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 18,189 (initial tests) · Method: failure items (major and minor) grouped by DVSA's defect tree; wordings with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
If a Mercedes-Benz 300 gets a noise, emissions and leaks advisory, how often does it fail next time?
5.0% of Mercedes-Benz 300 MOTs with a noise, emissions and leaks advisory were followed by a fail in the same group at the next MOT, typically 12.3 months and 623 miles later (1,888 advisories followed).
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 1,888 (advisories followed) · Method: the same vehicles followed to their next ordinary MOT · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
Other pages for this model
Mercedes-Benz 300 in Norway · Mercedes-Benz 300 in the Netherlands · Mercedes-Benz 300 by postcode area · Mercedes-Benz 300 body, chassis and structure failures · Mercedes-Benz 300 brakes failures · Mercedes-Benz 300 vehicle identification failures · Mercedes-Benz 300 lamps, reflectors and electrics failures · Mercedes-Benz 300 road wheels failures · Mercedes-Benz 300 seat belts and airbags failures · Mercedes-Benz 300 steering failures · Mercedes-Benz 300 suspension failures · Mercedes-Benz 300 tyres failures · Mercedes-Benz 300 visibility failures