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Bmw 520 vs Bmw X4: 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
87%
MOT pass rate · 15,179 vehicles
More reliable
Verdict: On MOT pass rate, the Bmw X4 is the more reliable of the two — 87% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Head to head

Measure Bmw 520 Bmw X4
MOT pass rate 78% 87% ✓
MOT failure rate 22% 13% ✓
Faults & advisories per test 1.6 1.0 ✓
Dangerous-fault share 3% ✓ 6%
Average mileage 134,460 mi 72,483 mi
Sample size (vehicles) 156,398 15,179

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

  1. Offside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  2. Nearside Rear Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  3. Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  4. Offside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
  5. Rear Brake pad(s) wearing thin (1.1.13 (a) (ii))
  6. Nearside Rear Child Seat fitted not allowing full inspection of adult belt

Reliability FAQ

On MOT pass rate, the Bmw X4 is the more reliable of the two — 87% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Full Bmw 520 report Full Bmw X4 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.