1998 Porsche Boxster — MOT failures & pass rate
The 1998 Porsche Boxster passed 78.7% of its 4,707 recorded MOT tests. That is effectively the same as coupes & convertibles of a similar age (21.5% fail rate), so the MOT record here is unremarkable in either direction. Failures cluster in lighting & signalling, emissions & environmental and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 12.1% of tests against 8.8% for the next-worst category.
At component level the recurring items are catalyst emissions, rigid brake pipes and headlamp aim — catalyst emissions alone was recorded 496 times.
Mileage is the strongest signal on the record: 9.0% of 0-30k cars fail, rising to 28.4% once past 150k — 3.1× the risk.
Brakes is the most common advisory, noted on 30.9% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 21.6% in 2021 to 19.5% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 12.1% | 571 |
| 2 | Emissions & environmental | 8.8% | 413 |
| 3 | Brakes | 6.1% | 286 |
| 4 | Suspension | 5.8% | 271 |
| 5 | Visibility | 4.4% | 207 |
| 6 | Tyres | 3.1% | 144 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Catalyst emissions | 496 |
| 2 | Rigid brake pipes | 263 |
| 3 | Headlamp aim | 244 |
| 4 | Headlamp | 206 |
| 5 | Position lamp | 159 |
| 6 | Wipers | 157 |
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 | 30.9% | 1,457 |
| 2 | Suspension | 23.5% | 1,105 |
| 3 | Tyres | 20.0% | 941 |
| 4 | Emissions & environmental | 12.6% | 592 |
| 5 | Lighting & signalling | 9.4% | 444 |
| 6 | Body, structure & corrosion | 6.3% | 295 |
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 | 144 | 9.0% |
| 30-60k | 641 | 14.7% |
| 60-90k | 1,411 | 17.8% |
| 90-120k | 1,425 | 24.1% |
| 120-150k | 836 | 27.0% |
| 150k+ | 222 | 28.4% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,007 | 21.6% |
| 2022 | 999 | 19.9% |
| 2023 | 976 | 22.6% |
| 2024 | 884 | 22.7% |
| 2025 | 841 | 19.5% |
What to check before buying a 1998 Boxster
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 12.1% of tests. Start there.
- Lighting & signalling (12.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (8.8% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Brakes (6.1% 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.
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 1998 Porsche Boxsters pass their MOT?
78.7% of the 4,707 1998 Porsche Boxster MOT tests in this dataset passed — a 21.3% fail rate.
What is the most common MOT failure on a 1998 Porsche Boxster?
Lighting & signalling, recorded in 12.1% of tests, followed by emissions & environmental (8.8%).
Does the 1998 Boxster get worse with mileage?
Its MOT fail rate rises from 9.0% in the 0-30k band to 28.4% in the 150k+ band.
Methodology & source. Based on 4,707 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.