Mercedes Benz Unknown (2018)
2018 Mercedes Benz Unknown
CarHunch is tracking 7,218 2018 Mercedes Benz Unknown vehicles on UK roads. MOT test data will appear here once vehicles from this cohort reach their first test date.
These 2018 Mercedes-Benz diesels are in serious trouble: only 1.6% pass their MOT first time, compared to the UK average of 80%, and the diesel-specific pass rate of just 0.5% suggests systemic mechanical issues across this cohort. Dangerous defects are rare (0.1%), but the overwhelming failure rate makes that irrelevant—this model has fundamental reliability problems.
With a median mileage of just 49,406 miles for six-year-old vehicles, these cars are failing early and often despite relatively low use, pointing to design or build faults rather than wear-and-tear. Before buying any 2018 Mercedes-Benz diesel, get a full pre-purchase inspection from a specialist mechanic and budget heavily for repairs, because routine MOT passes are clearly not the norm for this generation.
We have 7,218 2018 Mercedes Benz Unknown vehicles on record but don't have enough MOT test data to show reliable statistics for this cohort.
What to check before buying a 2018 Mercedes Benz Unknown
Practical pre-purchase checks for this age and model.
- 📋 Check the full MOT history. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. Enter the reg below for a full AI analysis.
- 🔍 Inspect for corrosion in person. Brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that's expensive to fix and can fail an MOT.
- 🛞 Check tyres and brakes. The most common advisory items at this age. Budget for replacement if they're near the limit — factor this into your offer price.
- 📄 Run an HPI check. The MOT history won't show outstanding finance, insurance write-offs, or stolen status — an HPI check will.
Before you buy a Mercedes Benz Unknown
MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.
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Pass Rate by Fuel Type
| Fuel type | Vehicles | Pass rate | Avg failures |
|---|---|---|---|
| Diesel (99%) | 7,121 | 0.5% | 0 |
| Diesel (1%) | 63 | 94.5% | 0.27 |
| Petrol (0%) | 33 | 58.3% | 0.3 |
| Electric (0%) | 1 | 0% | 0 |
Mileage Distribution
Most 2018 Mercedes Benz Unknown vehicles sit in the blue band. If the car you're looking at is outside it, it's either unusually low or high mileage for its age.
Half of all 2018 Mercedes Benz Unknown vehicles fall between 13,893 and 84,850 miles.
2018 Mercedes Benz Unknown — Still on the Road
Strong survival — 54 vehicles still getting MOTs in 2025, 100% of the peak.
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2019–2025.
Most Common MOT Issues — 2018 Mercedes Benz Unknown
Based on actual MOT test records for this model. Percentage shows how often each item appears across all vehicles in this cohort.
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18.5%
Offside Front Tyre worn close to legal limit/worn on edge
-
17.8%
Nearside Front Tyre worn close to legal limit/worn on edge
-
15.1%
Front Brake disc worn, pitted or scored, but not seriously weakened
-
12.3%
Oil leak, but not excessive
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10.3%
Front Brake pad(s) wearing thin
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10.3%
Parking brake efficiency below requirements
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8.9%
Nearside Rear Tyre worn close to legal limit/worn on edge
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7.5%
COVID-19 6 MONTH EXTENSION
Data covers a 3-year window centred on 2018. Counts include advisories and failures.
Found a specific Mercedes Benz Unknown?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.