1983 Porsche 911 — MOT failures & pass rate
Across 716 MOT tests, the 1983 Porsche 911 recorded an 87.4% pass rate. Against coupes & convertibles of a similar age (14.9% fail rate), the 1983 911 comes out 2.3pp better. Failures cluster in lighting & signalling, visibility and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 10.8% of tests against 6.6% for the next-worst category.
At component level the recurring items are headlamp aim, washers and rear fog lamp — headlamp aim alone was recorded 44 times.
Mileage matters less than usual here: the 1983 911 fails 16.3% of the time in the 0-30k band and 13.3% at 150k+, a spread of only 2.9 points.
Suspension is the most common advisory, noted on 11.7% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 15.2% in 2021 to 11.8% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 10.8% | 77 |
| 2 | Visibility | 6.6% | 47 |
| 3 | Brakes | 3.9% | 28 |
| 4 | Emissions & environmental | 2.1% | 15 |
| 5 | Body, structure & corrosion | 1.0% | 7 |
| 6 | Steering | 1.0% | 7 |
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 | 44 |
| 2 | Washers | 44 |
| 3 | Rear fog lamp | 29 |
| 4 | Position lamp | 26 |
| 5 | Service brake performance | 23 |
| 6 | Stop lamp | 12 |
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 | 11.7% | 84 |
| 2 | Emissions & environmental | 8.1% | 58 |
| 3 | Brakes | 6.0% | 43 |
| 4 | Tyres | 5.6% | 40 |
| 5 | Lighting & signalling | 3.5% | 25 |
| 6 | Body, structure & corrosion | 2.6% | 19 |
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 | 86 | 16.3% |
| 30-60k | 49 | 10.2% |
| 60-90k | 183 | 13.7% |
| 90-120k | 198 | 12.6% |
| 120-150k | 122 | 9.0% |
| 150k+ | 75 | 13.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 171 | 15.2% |
| 2022 | 198 | 11.6% |
| 2023 | 172 | 12.8% |
| 2024 | 99 | 10.1% |
| 2025 | 76 | 11.8% |
What to check before buying a 1983 911
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 10.8% of tests. Start there.
- Lighting & signalling (10.8% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (6.6% 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.
- Brakes (3.9% 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 1983 Porsche 911s pass their MOT?
87.4% of the 716 1983 Porsche 911 MOT tests in this dataset passed — a 12.6% fail rate.
What is the most common MOT failure on a 1983 Porsche 911?
Lighting & signalling, recorded in 10.8% of tests, followed by visibility (6.6%).
Does the 1983 911 get worse with mileage?
Its MOT fail rate rises from 16.3% in the 0-30k band to 13.3% in the 150k+ band.
Methodology & source. Based on 716 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.