1983 Ford Sierra — MOT failures & pass rate
Across 534 MOT tests, the 1983 Ford Sierra recorded an 87.6% pass rate. That is 2.6 percentage points worse than large family cars of a similar age, which fail at 9.7%. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 8.6% of tests against 5.4% for the next-worst category.
At component level the recurring items are headlamp aim, wipers and component mounting prescribed areas — headlamp aim alone was recorded 23 times.
Mileage matters less than usual here: the 1983 Sierra fails 15.1% of the time in the 0-30k band and 14.5% at 90-120k, a spread of only 0.5 points.
Suspension is the most common advisory, noted on 14.4% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 17.9% in 2021 to 16.0% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 8.6% | 46 |
| 2 | Suspension | 5.4% | 29 |
| 3 | Brakes | 4.1% | 22 |
| 4 | Visibility | 3.8% | 20 |
| 5 | Body, structure & corrosion | 2.8% | 15 |
| 6 | Emissions & environmental | 2.4% | 13 |
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 | 23 |
| 2 | Wipers | 16 |
| 3 | Component mounting prescribed areas | 15 |
| 4 | Stop lamp | 13 |
| 5 | Non catalyst emissions | 11 |
| 6 | Washers | 11 |
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 | 14.4% | 77 |
| 2 | Brakes | 11.8% | 63 |
| 3 | Body, structure & corrosion | 9.0% | 48 |
| 4 | Emissions & environmental | 8.6% | 46 |
| 5 | Other defects | 5.6% | 30 |
| 6 | Tyres | 5.4% | 29 |
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 | 159 | 15.1% |
| 30-60k | 160 | 10.6% |
| 60-90k | 157 | 10.2% |
| 90-120k | 55 | 14.5% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 151 | 17.9% |
| 2022 | 163 | 12.9% |
| 2023 | 110 | 6.4% |
| 2024 | 60 | 5.0% |
| 2025 | 50 | 16.0% |
What to check before buying a 1983 Sierra
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 8.6% of tests. Start there.
- Lighting & signalling (8.6% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (5.4% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Brakes (4.1% 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 1983 Ford Sierras pass their MOT?
87.6% of the 534 1983 Ford Sierra MOT tests in this dataset passed — a 12.4% fail rate.
What is the most common MOT failure on a 1983 Ford Sierra?
Lighting & signalling, recorded in 8.6% of tests, followed by suspension (5.4%).
Does the 1983 Sierra get worse with mileage?
Its MOT fail rate rises from 15.1% in the 0-30k band to 14.5% in the 90-120k band.
Methodology & source. Based on 534 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.