Diesel BMW 420: MOT pass rate
84.4% of diesel BMW 420s pass the MOT first time, measured across 41,928 DVSA tests on that fuel type alone. Average mileage at test was 75,623.
Diesel against the other BMW 420 versions
| Fuel | Pass rate | Tests |
|---|---|---|
| Diesel | 84.4% | 41,928 |
| Petrol | 87.1% | 20,942 |
| All BMW 420 | 85.3% | 62,870 |
Why the fuel type changes the number
Diesels carry DPFs, EGR valves and stricter smoke limits, so emissions and exhaust faults account for failures petrol cars never see.
On the BMW 420 specifically, petrol is the strongest at 87.1%, and this diesel version sits 0.9 points below the 85.3% model average.
What it means if you are buying one
There is little to choose between fuel types on this model, so decide on running costs and mileage rather than MOT record. Check the exact car, decode the VIN and check the mileage before you bid.
Mileage is part of the answer
The average diesel BMW 420 had covered 75,623 miles at test, against 48,201 for the petrol. That is a shade above the middle of the range, still ordinary wear rather than a red flag, but worth checking against the service book for the car's age.
Fuel type and mileage are tangled together: diesels are usually bought by higher-mileage drivers, so some of any gap between fuels is the miles rather than the engine. The per-year figures on the BMW 420 page separate age from fuel if you want to isolate one.
Other BMW 420 fuel types
- Petrol BMW 420 - 87.1%