BMW 420 (2018)
2018 BMW 420
CarHunch analysed 10,491 real MOT records for the 2018 BMW 420. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
The 2018 BMW 420 passes its MOT first time in 89.8% of cases, well above the UK average of 80%, though nearly three in ten examples have recorded a dangerous defect at some point—a notably high proportion that warrants a thorough pre-purchase inspection. Petrol and diesel versions perform almost identically (90.1% and 89.5% pass rates respectively), so fuel choice won't materially affect reliability here.
These 420s average just 42,382 miles at test time, suggesting they're low-mileage examples that haven't yet accumulated significant wear, yet they're already averaging 0.67 failures per vehicle—more than would be typical for their age and distance. The 4.4 advisories per car point to niggling electrical and trim issues common to modern BMWs; before buying, get an independent diagnostic scan to check for hidden fault codes that MOT inspectors won't always catch.
What to check before buying a 2018 BMW 420
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.
- ⚠️ 28.3% 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 BMW 420
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 (52%) | 5,448 | 89.5% | 0.69 |
| Petrol (48%) | 5,043 | 90.1% | 0.66 |
Mileage Distribution
Most 2018 BMW 420 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 BMW 420 vehicles fall between 34,016 and 57,572 miles.
2018 BMW 420 — Still on the Road
Strong survival — 9,711 vehicles still getting MOTs in 2025, 96% 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 BMW 420
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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35.5%
Nearside Rear Tyre worn close to legal limit/worn on edge
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34.8%
Offside Rear Tyre worn close to legal limit/worn on edge
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27.8%
Offside Front Tyre worn close to legal limit/worn on edge
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27.5%
Nearside Front Tyre worn close to legal limit/worn on edge
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27.3%
Rear Brake pad(s) wearing thin
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15.4%
Front Brake pad(s) wearing thin
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11%
Offside Front Play in steering rack inner joint(s) ()
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10.1%
Front Brake disc worn, pitted or scored, but not seriously weakened
Data covers a 3-year window centred on 2018. Counts include advisories and failures.
Found a specific BMW 420?
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