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Bmw 520 vs Bmw R66: 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 R66
84%
MOT pass rate · 5 vehicles
Verdict: On MOT pass rate the Bmw 520 (78%) and Bmw R66 (84%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Bmw 520 Bmw R66
MOT pass rate 78% 84% ✓
MOT failure rate 22% 16% ✓
Faults & advisories per test 1.6 0.3 ✓
Dangerous-fault share 3% 0% ✓
Average mileage 134,460 mi 41,270 mi
Sample size (vehicles) 156,398 5

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 R66

  1. Front Tyre worn close to the legal limit (4.1.3(ii))
  2. Rear Tyre worn close to the legal limit (4.1.3(ii))
  3. Headlamp aim too low (1.6)
  4. Front Roller brake test indicates slight fluctuation of brake effort (3.3.A1d)
  5. Rear Roller brake test indicates slight fluctuation of brake effort (3.3.A1d)
  6. Stop lamp does not illuminate immediately a brake applies (1.3.1a)

Reliability FAQ

On MOT pass rate the Bmw 520 (78%) and Bmw R66 (84%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Bmw 520 report Full Bmw R66 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.