Mercedes Benz B Class (2018)
2018 Mercedes Benz B Class
CarHunch analysed 3,875 real MOT records for the 2018 Mercedes Benz B Class. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
The 2018 Mercedes-Benz B-Class passes its MOT at 89.9%, well above the UK average of 80%, which is genuinely solid—but 23.4% of these vehicles have recorded a dangerous defect at some point, a red flag worth investigating on any used example you're considering. Petrol models perform better (91.3% pass rate) than their diesel counterparts (88.6%), so fuel type does matter for this generation.
These cars are running relatively low mileage for their age at a median of 32,567 miles, suggesting they've been treated as cherished family runabouts rather than workhorses. The average vehicle racks up 0.68 failures and 4.1 advisories per test, which points to minor wear rather than systematic problems—so get a pre-purchase inspection done and focus on brake and suspension components, which typically dominate that advisory count.
Petrol vs Diesel
Pass rate difference of 2.7 percentage points — worth knowing if you're choosing between the two.
What to check before buying a 2018 Mercedes Benz B Class
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.
- ⚠️ 23.4% of these vehicles have had a dangerous defect recorded. Enter the reg below — the full MOT history will show exactly what was flagged and whether it was resolved.
- 📄 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 B Class
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 (50%) | 1,940 | 88.6% | 0.78 |
| Petrol (50%) | 1,933 | 91.3% | 0.57 |
| Electric (0%) | 1 | 83.3% | 1 |
| Other (0%) | 1 | 100% | 0 |
Mileage Distribution
Most 2018 Mercedes Benz B Class 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 B Class vehicles fall between 23,660 and 43,403 miles.
2018 Mercedes Benz B Class — Still on the Road
Strong survival — 3,785 vehicles still getting MOTs in 2025, 99% of the peak.
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2021–2025.
MOT History Averages
Most Common MOT Issues — 2018 Mercedes Benz B Class
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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34.3%
Offside Front Tyre worn close to legal limit/worn on edge
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33.4%
Nearside Front Tyre worn close to legal limit/worn on edge
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26.9%
Offside Rear Tyre slightly damaged/cracking or perishing
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25.4%
Nearside Rear Tyre slightly damaged/cracking or perishing
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23.4%
Front Brake pad(s) wearing thin
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12.1%
Nearside Rear Child Seat fitted not allowing full inspection of adult belt ()
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11.3%
COVID-19 6 MONTH EXTENSION
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11%
Rear Brake pad(s) wearing thin
Data covers a 3-year window centred on 2018. Counts include advisories and failures.
Found a specific Mercedes Benz B Class?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.