Mercedes Unknown (2014)
2014 Mercedes Unknown
CarHunch analysed 1,202 real MOT records for the 2014 Mercedes Unknown. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
This 2014 Mercedes cohort is a serious reliability red flag: only 5.4% pass first time, compared to the UK average of 80%, with diesel variants performing even worse at 3.5% pass rates. Dangerous defects are rare at 0.5%, but the catastrophic pass rate means systematic problems are almost certainly present across the fleet.
The median mileage of 49,052 miles is unusually low for a 10-year-old car, suggesting these vehicles are either heavily driven between MOTs or culled early—the average of 126,795 miles confirms wide variation in condition. With only 0.04 failures and 0.2 advisories per vehicle on average, the test data itself suggests minor wear rather than major faults, which makes the near-total failure rate puzzling and points to a specific recurring defect affecting almost every example. Before buying, request the full MOT history to identify what fault is failing every test—that answer will tell you whether it's fixable or a deal-breaker.
What to check before buying a 2014 Mercedes 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 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 (96%) | 1,155 | 3.5% | 0.03 |
| Petrol (3%) | 38 | 44.6% | 0.16 |
| Diesel (1%) | 9 | 91.7% | 0.22 |
Mileage Distribution
Most 2014 Mercedes 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 2014 Mercedes Unknown vehicles fall between 25,778 and 108,214 miles.
2014 Mercedes Unknown — Still on the Road
Strong survival — 44 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 2017–2025.
MOT History Averages
Most Common MOT Issues — 2014 Mercedes 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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15.4%
Nearside Rear Tyre worn close to legal limit/worn on edge
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13.8%
Offside Front Brake disc worn, pitted or scored, but not seriously weakened
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13.8%
Nearside Front Brake disc worn, pitted or scored, but not seriously weakened
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13.1%
Offside Front Tyre worn close to legal limit/worn on edge
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11.5%
Offside Rear Tyre worn close to legal limit/worn on edge
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11.5%
Offside Front Brake pipe corroded, covered in grease or other material
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10.8%
Nearside Front Suspension arm ball joint has slight play
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10.8%
Parking brake efficiency below requirements
Data covers a 3-year window centred on 2014. Counts include advisories and failures.
Found a specific Mercedes Unknown?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.