2018 Mercedes-Benz Slc MOT pass rate: 90.4% (4,402 tests)
Is the 2018 Slc getting worse?
Pass rate of 2018-registered cars across recent test years:
| Test year | Pass rate | |
|---|---|---|
| 2023 | 91.6% +3.5 vs same-age |
|
| 2024 | 89.7% +3.5 vs same-age |
|
| 2025 | 90.0% +5.2 vs same-age |
The raw rate normally falls as cars age. The “vs same-age” figure compares this cohort with all UK cars registered in the same year, so normal ageing is not mistaken for a bad model year.
What fails on a 2018 Slc
| # | System | Defects recorded | Share |
|---|---|---|---|
| 1 | Tyres | 358 | 55.6% |
| 2 | Suspension | 71 | 11.0% |
| 3 | Brakes | 64 | 9.9% |
| 4 | Lamps, reflectors and electrical equipment | 42 | 6.5% |
| 5 | Noise, emissions and leaks | 32 | 5.0% |
| 6 | Road Wheels | 24 | 3.7% |
All Slc years compared
| Registration year | Tests | Pass rate | Vs same-age | Median mileage |
|---|---|---|---|---|
| 2016 | 6,669 | 85.9% | +4.6 pts | 37,359 |
| 2017 | 10,191 | 86.1% | +2.1 pts | 32,089 |
| 2018 (this page) | 4,402 | 90.4% | +4.1 pts | 25,549 |
| 2019 | 2,926 | 92.0% | +3.6 pts | 18,656 |
- Free MOT history checkThe exact car’s failures, advisories and mileage trail — sellers can’t edit it
- Topdon OBD2 scannersTopdon diagnostic scanners with full-system readouts
- XTOOL diagnostic toolsXTOOL code readers for petrol and diesel cars
- Autel UK testersAutel professional-grade diagnostic testers
FAQs
Is a 2018 Mercedes-Benz Slc reliable?
2018-registered examples passed 90.4% of their MOT tests (4,402 tests, 2023–2025), +4.1 points versus all UK cars registered in the same year. At roughly 8 years old with a median 25,549 miles, condition now varies car by car — always check the individual MOT history.
What mileage is too high for a 2018 Slc?
The median tested example shows 25,549 miles. Anything far beyond that isn't automatically bad — a motorway-mile car with consistent service records often beats a low-mileage school-run car — but price accordingly and scrutinise the mileage trail for gaps or drops.
Should I buy the petrol or diesel 2018 Slc?
In this cohort petrols pass 91.0% of tests against 85.8% for diesels. Mileage and use can explain part of that gap, so treat it as a reason to inspect DPF and emissions history, not a fuel-type verdict.
Source: DVSA Anonymised MOT tests and results, 2023–2025 extracts (96 million Class 4 initial tests; retests excluded). Only vehicles old enough for a routine first MOT are included. Age-adjusted figures compare the model-year cohort with all vehicles of the same registration year tested in the same calendar year. Contains public sector information licensed under OGL v3.0.