Bmw 420d m sport auto vs Bmw 520: reliability comparison
MOT pass rates, common faults and mileage compared from real UK MOT data.
Bmw 420d m sport auto
92%
MOT pass rate · 1,457 vehicles
More reliable
Bmw 520
78%
MOT pass rate · 156,398 vehicles
Verdict: On MOT pass rate, the Bmw 420d m sport auto is the more reliable of the two — 92% pass first time versus 78%. It's one signal among several; check the full breakdown below.
Head to head
| Measure | Bmw 420d m sport auto | Bmw 520 |
|---|---|---|
| MOT pass rate | 92% ✓ | 78% |
| MOT failure rate | 8% ✓ | 22% |
| Faults & advisories per test | 0.0 ✓ | 1.6 |
| Dangerous-fault share | — ✓ | 3% |
| Average mileage | 88,650 mi | 134,460 mi |
| Sample size (vehicles) | 1,457 | 156,398 |
Most common faults
Bmw 420d m sport auto
No fault breakdown available.
Bmw 520
- Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
- Offside Rear Tyre worn close to the legal limit (4.1.E.1)
- Offside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
- Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
- Under-trays fitted obscuring some underside components
- Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
Reliability FAQ
On MOT pass rate, the Bmw 420d m sport auto is the more reliable of the two — 92% pass first time versus 78%. It's one signal among several; check the full breakdown below.
Full Bmw 420d m sport auto report Full Bmw 520 report Most reliable cars
Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.