1988 Porsche 911 — MOT failures & pass rate
The 1988 Porsche 911 passed 88.1% of its 1,996 recorded MOT tests. That is 4.9 percentage points better than coupes & convertibles of a similar age, which fail at 16.9%. Failures cluster in lighting & signalling, visibility and brakes.
What the MOT record shows
Lighting & signalling dominates the failure mix at 8.3% of all tests — 4.1 points clear of visibility, so it is the first thing to check.
At component level the recurring items are headlamp aim, washers and service brake performance — headlamp aim alone was recorded 97 times.
A 150k+ example is materially riskier than a 0-30k one: 18.0% versus 3.7%.
Advisories point at the next bill rather than this one: suspension was flagged on 8.8% of tests without failing them.
The trend is improving — the fail rate fell from 15.0% in 2021 to 11.4% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 8.3% | 166 |
| 2 | Visibility | 4.3% | 85 |
| 3 | Brakes | 3.6% | 71 |
| 4 | Suspension | 1.9% | 39 |
| 5 | Emissions & environmental | 1.8% | 37 |
| 6 | Body, structure & corrosion | 1.6% | 31 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 97 |
| 2 | Washers | 74 |
| 3 | Service brake performance | 56 |
| 4 | Rear fog lamp | 49 |
| 5 | Headlamp | 35 |
| 6 | Stop lamp | 32 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 8.8% | 176 |
| 2 | Brakes | 8.2% | 163 |
| 3 | Emissions & environmental | 6.9% | 138 |
| 4 | Tyres | 6.8% | 136 |
| 5 | Body, structure & corrosion | 3.1% | 62 |
| 6 | Lighting & signalling | 2.5% | 49 |
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 | 163 | 3.7% |
| 30-60k | 245 | 6.5% |
| 60-90k | 475 | 11.2% |
| 90-120k | 581 | 13.6% |
| 120-150k | 326 | 14.4% |
| 150k+ | 206 | 18.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 380 | 15.0% |
| 2022 | 406 | 11.6% |
| 2023 | 401 | 10.7% |
| 2024 | 396 | 11.1% |
| 2025 | 413 | 11.4% |
What to check before buying a 1988 911
On a 1988 911, lighting & signalling is what the MOT record says goes wrong most — it appeared in 8.3% of tests. Check these areas before you commit.
- Lighting & signalling (8.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (4.3% 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.
- Brakes (3.6% 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 1988 Porsche 911s pass their MOT?
88.1% of the 1,996 1988 Porsche 911 MOT tests in this dataset passed — a 11.9% fail rate.
What is the most common MOT failure on a 1988 Porsche 911?
Lighting & signalling, recorded in 8.3% of tests, followed by visibility (4.3%).
Does the 1988 911 get worse with mileage?
Its MOT fail rate rises from 3.7% in the 0-30k band to 18.0% in the 150k+ band.
Methodology & source. Based on 1,996 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.