2018 Porsche Boxster — MOT failures & pass rate
The 2018 Porsche Boxster passed 95.0% of its 5,428 recorded MOT tests. That is 4.1 percentage points better than coupes & convertibles of a similar age, which fail at 9.0%. Failures cluster in tyres, lighting & signalling and visibility.
What the MOT record shows
No single area dominates — tyres (3.7%) and lighting & signalling (0.9%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, headlamp aim and washers — tread depth alone was recorded 110 times.
Mileage is the strongest signal on the record: 4.6% of 0-30k cars fail, rising to 13.6% once past 60-90k — 3.0× the risk.
Tyres is the most common advisory, noted on 15.9% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 3.7% | 200 |
| 2 | Lighting & signalling | 0.9% | 51 |
| 3 | Visibility | 0.6% | 35 |
| 4 | Other defects | 0.3% | 16 |
| 5 | Brakes | 0.3% | 14 |
| 6 | Suspension | 0.2% | 12 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 110 |
| 2 | Headlamp aim | 50 |
| 3 | Washers | 29 |
| 4 | Registration plates | 27 |
| 5 | Tyre pressure monitoring system | 11 |
| 6 | Shock absorbers | 9 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 15.9% | 864 |
| 2 | Brakes | 2.9% | 160 |
| 3 | Other defects | 2.2% | 121 |
| 4 | Visibility | 1.7% | 93 |
| 5 | Suspension | 0.8% | 44 |
| 6 | Emissions & environmental | 0.5% | 27 |
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 | 4,229 | 4.6% |
| 30-60k | 1,138 | 6.0% |
| 60-90k | 59 | 13.6% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,139 | 5.7% |
| 2022 | 1,119 | 4.4% |
| 2023 | 1,082 | 5.3% |
| 2024 | 1,046 | 5.0% |
| 2025 | 1,042 | 4.5% |
What to check before buying a 2018 Boxster
The failure pattern for this year is specific enough to inspect against: tyres accounted for 3.7% of tests. Start there.
- Tyres (3.7% 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.
- Lighting & signalling (0.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (0.6% 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 Porsche Boxsters pass their MOT?
95.0% of the 5,428 2018 Porsche Boxster MOT tests in this dataset passed — a 5.0% fail rate.
What is the most common MOT failure on a 2018 Porsche Boxster?
Tyres, recorded in 3.7% of tests, followed by lighting & signalling (0.9%).
Does the 2018 Boxster get worse with mileage?
Its MOT fail rate rises from 4.6% in the 0-30k band to 13.6% in the 60-90k band.
Methodology & source. Based on 5,428 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.