2018 Mazda 3 — MOT failures & pass rate
Across 39,185 MOT tests, the 2018 Mazda 3 recorded an 89.8% pass rate. Small family cars of a similar age fail at 10.4%, so the 2018 3 sits squarely on the average. Failures cluster in tyres, brakes and visibility.
What the MOT record shows
No single area dominates — tyres (4.0%) and brakes (3.5%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are brake pads, wipers and coil spring — brake pads alone was recorded 1,172 times.
Mileage is the strongest signal on the record: 6.4% of 0-30k cars fail, rising to 19.1% once past 120-150k — 3.0× the risk.
Split by fuel, diesel examples fail 4.5pp more often than petrol ones (14.3% vs 9.8%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 24.1% of tests without failing them.
The trend is worsening — 5.6% of tests failed in 2021 against 13.0% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.0% | 1,560 |
| 2 | Brakes | 3.5% | 1,353 |
| 3 | Visibility | 2.9% | 1,143 |
| 4 | Suspension | 2.5% | 990 |
| 5 | Lighting & signalling | 1.7% | 649 |
| 6 | Seat belts & restraints | 0.2% | 64 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Brake pads | 1,172 |
| 2 | Wipers | 1,133 |
| 3 | Coil spring | 762 |
| 4 | Tread depth | 470 |
| 5 | Headlamp aim | 448 |
| 6 | Brake discs | 305 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 24.1% | 9,437 |
| 2 | Tyres | 22.5% | 8,827 |
| 3 | Other defects | 6.5% | 2,553 |
| 4 | Visibility | 3.8% | 1,470 |
| 5 | Suspension | 2.2% | 870 |
| 6 | Road wheels | 1.1% | 423 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 17,500 | 6.4% |
| 30-60k | 17,214 | 12.7% |
| 60-90k | 3,755 | 15.2% |
| 90-120k | 617 | 17.2% |
| 120-150k | 84 | 19.1% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 35,844 | 9.8% |
| Diesel | 3,341 | 14.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 7,608 | 5.6% |
| 2022 | 7,720 | 8.3% |
| 2023 | 7,933 | 11.2% |
| 2024 | 7,916 | 12.6% |
| 2025 | 8,008 | 13.0% |
What to check before buying a 2018 3
On a 2018 3, tyres is what the MOT record says goes wrong most — it appeared in 4.0% of tests. Check these areas before you commit.
- Tyres (4.0% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Brakes (3.5% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
- Visibility (2.9% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2018 Mazda 3s pass their MOT?
89.8% of the 39,185 2018 Mazda 3 MOT tests in this dataset passed — a 10.2% fail rate.
What is the most common MOT failure on a 2018 Mazda 3?
Tyres, recorded in 4.0% of tests, followed by brakes (3.5%).
Does the 2018 3 get worse with mileage?
Its MOT fail rate rises from 6.4% in the 0-30k band to 19.1% in the 120-150k band.
Methodology & source. Based on 39,185 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.