Ford Fiesta vs Ford Sierra diesel turbo: reliability comparison
MOT pass rates, common faults and mileage compared from real UK MOT data.
Ford Fiesta
73%
MOT pass rate · 2,835,744 vehicles
Ford Sierra diesel turbo
—
MOT pass rate · 67 vehicles
Verdict: On MOT pass rate the Ford Fiesta (73%) and Ford Sierra diesel turbo (0%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Head to head
| Measure | Ford Fiesta | Ford Sierra diesel turbo |
|---|---|---|
| MOT pass rate | 73% ✓ | 0% |
| MOT failure rate | 27% | 0% ✓ |
| Faults & advisories per test | 2.1 | 0.0 ✓ |
| Dangerous-fault share | 2% | — ✓ |
| Average mileage | 84,529 mi | — |
| Sample size (vehicles) | 2,835,744 | 67 |
Most common faults
Ford Fiesta
- Nearside Front Tyre worn close to the legal limit (4.1.E.1)
- Offside Front Tyre worn close to the legal limit (4.1.E.1)
- Offside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
- Nearside Front Tyre worn close to legal limit/worn on edge (5.2.3 (e))
- Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
- Offside Rear Brake pipe slightly corroded (3.6.B.2c)
Ford Sierra diesel turbo
No fault breakdown available.
Reliability FAQ
On MOT pass rate the Ford Fiesta (73%) and Ford Sierra diesel turbo (0%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Full Ford Fiesta report Full Ford Sierra diesel turbo 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.