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Bmw 520 vs Bmw X4 m40i mhev auto: reliability comparison

MOT pass rates, common faults and mileage compared from real UK MOT data.

Bmw 520
78%
MOT pass rate · 156,398 vehicles
Bmw X4 m40i mhev auto
93%
MOT pass rate · 604 vehicles
More reliable
Verdict: On MOT pass rate, the Bmw X4 m40i mhev auto is the more reliable of the two — 93% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Head to head

Measure Bmw 520 Bmw X4 m40i mhev auto
MOT pass rate 78% 93% ✓
MOT failure rate 22% 7% ✓
Faults & advisories per test 1.6 0.6 ✓
Dangerous-fault share 3% ✓ 6%
Average mileage 134,460 mi 26,808 mi
Sample size (vehicles) 156,398 604

Most common faults

Bmw 520

  1. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  2. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  3. Offside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  4. Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  5. Under-trays fitted obscuring some underside components
  6. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))

Bmw X4 m40i mhev auto

  1. Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  2. Offside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  3. Offside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  4. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  5. Windscreen damaged but not adversely affecting driver's view (3.2 (a) (i))
  6. Offside Front Tyre slightly damaged/cracking or perishing (5.2.3 (d) (ii))

Reliability FAQ

On MOT pass rate, the Bmw X4 m40i mhev auto is the more reliable of the two — 93% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Full Bmw 520 report Full Bmw X4 m40i mhev auto 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.