Mercedes-Benz C-Class W205: best and worst years, and what goes wrong
How each year of the Mercedes-Benz C-Class W205 did at the MOTs done during 2023–2025, compared with other cars the same age, the weak spots that keep coming up, and what to check before you buy one. From 611,910 MOT tests.
Which Mercedes-Benz C-Class W205 years are best and worst at their MOT?
First-time MOT pass rate for each year of the Mercedes-Benz C-Class W205, against all cars registered the same year. Older cars fail more, so the comparison with cars the same age is what matters.
| Year | Pass first time | All cars that year | Stands out | MOT tests |
|---|---|---|---|---|
| 2014* | 76% | 70% +6 | Ball joint 1.9× usual | 77,294 |
| 2015 | 79% | 74% +5 | Ball joint 2.9× usual | 103,655 |
| 2016 | 81% | 77% +4 | Ball joint 3.4× usual | 110,990 |
| 2017 | 83% | 80% +3 | Ball joint 4.9× usual | 118,916 |
| 2018 | 85% | 83% +2 | Ball joint 4.5× usual | 84,961 |
| 2019 | 87% | 85% +2 | Ball joint 4× usual | 73,990 |
| 2020 | 87% | 87% +0 | Ball joint 5× usual | 30,441 |
| 2021 | 87% | 87% +0 | Nothing unusual | 11,663 |
Common Mercedes-Benz C-Class W205 MOT failures, year after year
Parts flagged at MOT well above the usual rate for cars the same age, in more than one year of this generation. Repeat findings like these are much less likely to be chance.
- Ball jointup to 5× usual
Stands out in 6 years: 2020, 2019, 2018, 2017, 2016, 2015.
Rough price £60–£150 (one joint) ClickMechanicAt the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.
- Engine warning lightup to 2.3× usual
Stands out in 3 years: 2017, 2016, 2015.
Rough price £10–£80 our estimateAt the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.
What usually goes wrong with the Mercedes-Benz C-Class W205?
From owners, mechanics and UK buying guides, in our own words. Not every car will have them.
Diesel emissions system faults
Particulate filter, NOx sensor and AdBlue problems are the main worry on diesels, especially ones used for short trips.
Check: Watch for emissions or AdBlue warnings on the dash, and ask what journeys it’s done.
Air suspension
Cars with air suspension can develop expensive faults that need a specialist.
Check: Check the car sits level all round, look for uneven front tyre wear, and watch for suspension warnings.
Petrol smell or leaks (petrol)
Petrol models can leak fuel from the pump area or crack plastic air pipes.
Check: Smell around the car after a cold start, and listen for rough idle.
Automatic gearbox behaviour
Some automatics shift inconsistently.
Check: Drive through every gear at different speeds. Any odd or jerky changes should be priced in or a reason to walk away.
Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting each car's main test of the year (not retests). A weak spot needs at least 30 cars flagged and must stay 1.5× the usual rate even at the cautious end of a 95% confidence range. Generation years are approximate: cars registered in a changeover year (*) can be either generation. How we score
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