1,608 tests in 2025
MG Zr reliability and MOT pass rate
72.5% passed first time. The 27.5% fail rate is 4.9 points worse than the all-car average, on a median example 21 years old with 81,011 miles.
Pass rate
72.5%
22.6% of all cars failed; 27.5% of these did.
Fixed on the day
6.8%
Passed after a defect was put right during the visit.
Median at test
81,011 mi
21 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 0 | — |
| 6-9 years | 0 | — |
| 10-13 years | 0 | — |
| 14+ years | 1,608 | 27.5% |
What the Zr fails on
Share of failed tests with at least one fail item in each DVSA inspection section. A test can fail in several sections at once.
- Lamps, reflectors and electrical equipment7 dangerous42.5%
- Body, chassis, structure11 dangerous35.7%
- Brakes22 dangerous35.7%
- Noise, emissions and leaks1 dangerous25.6%
- Suspension7 dangerous24.9%
- Tyres76 dangerous18.1%
- Visibility12.2%
- Seat belts and supplementary restraint systems1 dangerous11.3%
Is the Zr getting worse?
The fail rate fell 4.2 points to 27.4% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 0.2 points, so it is holding up better than the fleet average for its age.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 2,777 | 18 | 31.6% | 22.5% | |
| 2023 | 2,385 | 19 | 31.1% | 22.8% | |
| 2024 | 1,725 | 20 | 30.8% | 23.2% | |
| 2025 | 1,600 | 21 | 27.4% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical Zr at its test that year, and it is the number to watch: across the whole fleet each extra year of age adds roughly 1.9 points to the fail rate, so a model whose age and fail rate rise together is simply getting older.
The exact defects that fail it
Every failure item DVSA recorded against a Zr in 2025, counted by how many tests each one appeared on.
- 1Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt86 tests
- 2Component mounting prescribed areas: prescribed area excessively corroded significantly reducing structural strength68 tests
- 3Service brake performance: excessively binding46 tests
- 4Rbt (sp): efficiency below requirements46 tests
- 5Exhaust system: has a major leak of exhaust gases41 tests
- 6Position lamp: not working38 tests
- 7Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits38 tests
- 8Stop lamp: not working36 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical Zr collects 3.05 of them per test, and these are the ones that come up most. Treat it as the running-repairs list for the next year or two.
- 1Condition: has a tear, caused by separation or partial failure of its structure179 tests
- 2Engine oil leaks: leaking excessively from engine165 tests
- 3Tread depth: tread depth below requirements of 1.6mm149 tests
- 4Brake discs: in such a condition that it is seriously weakened123 tests
- 5Exhaust system: has a major leak of exhaust gases105 tests
- 6Component mounting prescribed areas: prescribed area excessively corroded significantly reducing structural strength101 tests
- 7Service brake performance: excessively binding101 tests
- 8Rigid brake pipes: excessively corroded91 tests
Questions
What is the MG Zr MOT pass rate?
72.5% of the 1,608 MG Zr first-attempt MOTs in 2025 passed. The fail rate of 27.5% compares with 22.6% across all cars. A further 6.8% passed after a defect was fixed during the test visit.
What does a MG Zr usually fail on?
The single most common failure is "Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt", recorded on 86 failed tests, followed by "Component mounting prescribed areas: prescribed area excessively corroded significantly reducing structural strength" and "Service brake performance: excessively binding". By section, lamps, reflectors and electrical equipment appears in 42.5% of failures, body, chassis, structure appears in 35.7% of failures, brakes appears in 35.7% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was n/a%; at 14+ years it was 27.5%. The median MG Zr tested in 2025 was 21 years old with 81,011 miles.
Is the MG Zr getting less reliable?
The fail rate fell 4.2 points to 27.4% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 0.2 points, so it is holding up better than the fleet average for its age.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (OGL v3, retrieved 2026-09-12). DVSA records newer cars trim by trim; this page adds every Zr trim together. Year-on-year figures come from the same DVSA extracts for 2026 and earlier years. Full method on the pass rates hub.
Other MG models
Checking a particular Zr?
The odds above are the model. The car in front of you has its own record: every test, every advisory, the mileage at each one.
Due a test? Find an approved MOT station near you.