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Bmw 520 vs Bmw Z1: 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 Z1
85%
MOT pass rate · 298 vehicles
More reliable
Verdict: On MOT pass rate, the Bmw Z1 is the more reliable of the two — 85% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Head to head

Measure Bmw 520 Bmw Z1
MOT pass rate 78% 85% ✓
MOT failure rate 22% 15% ✓
Faults & advisories per test 1.6 0.9 ✓
Dangerous-fault share 3% 1% ✓
Average mileage 134,460 mi 56,610 mi
Sample size (vehicles) 156,398 298

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 Z1

  1. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  2. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  3. Oil leak
  4. Rear Exhaust has part of the system slightly deteriorated (7.1.1a)
  5. Horn not working (1.6.2a)
  6. Under-trays fitted obscuring some underside components

Reliability FAQ

On MOT pass rate, the Bmw Z1 is the more reliable of the two — 85% pass first time versus 78%. It's one signal among several; check the full breakdown below.

Full Bmw 520 report Full Bmw Z1 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.