2018 MG GS — MOT failures & pass rate
Across 5,354 MOT tests, the 2018 MG GS recorded an 88.1% pass rate. All cars of a similar age fail at 11.1%, so the 2018 GS sits squarely on the average. Failures cluster in lighting & signalling, brakes and tyres.
What the MOT record shows
Lighting & signalling dominates the failure mix at 7.5% of all tests — 3.0 points clear of brakes, so it is the first thing to check.
At component level the recurring items are headlamp aim, brake pads and tyre pressure monitoring system — headlamp aim alone was recorded 384 times.
A 90-120k example is materially riskier than a 0-30k one: 24.1% versus 7.1%.
Advisories point at the next bill rather than this one: tyres was flagged on 23.1% of tests without failing them.
The trend is worsening — 5.2% of tests failed in 2021 against 16.5% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 7.5% | 401 |
| 2 | Brakes | 4.5% | 239 |
| 3 | Tyres | 4.4% | 235 |
| 4 | Seat belts & restraints | 2.0% | 105 |
| 5 | Visibility | 1.6% | 86 |
| 6 | Emissions & environmental | 1.4% | 73 |
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 | 384 |
| 2 | Brake pads | 122 |
| 3 | Tyre pressure monitoring system | 100 |
| 4 | Tread depth | 98 |
| 5 | Anti-lock braking system | 94 |
| 6 | SRS malfunction indicator lamp | 89 |
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 | 23.1% | 1,235 |
| 2 | Brakes | 18.6% | 997 |
| 3 | Other defects | 9.3% | 495 |
| 4 | Suspension | 4.3% | 230 |
| 5 | Lighting & signalling | 2.7% | 144 |
| 6 | Visibility | 2.5% | 133 |
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 | 2,157 | 7.1% |
| 30-60k | 2,523 | 13.9% |
| 60-90k | 590 | 18.5% |
| 90-120k | 79 | 24.1% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 983 | 5.2% |
| 2022 | 1,034 | 7.6% |
| 2023 | 1,095 | 12.2% |
| 2024 | 1,115 | 16.6% |
| 2025 | 1,127 | 16.5% |
What to check before buying a 2018 GS
On a 2018 GS, lighting & signalling is what the MOT record says goes wrong most — it appeared in 7.5% of tests. Check these areas before you commit.
- Lighting & signalling (7.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (4.5% 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.
- Tyres (4.4% 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.
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 MG GSs pass their MOT?
88.1% of the 5,354 2018 MG GS MOT tests in this dataset passed — a 11.9% fail rate.
What is the most common MOT failure on a 2018 MG GS?
Lighting & signalling, recorded in 7.5% of tests, followed by brakes (4.5%).
Does the 2018 GS get worse with mileage?
Its MOT fail rate rises from 7.1% in the 0-30k band to 24.1% in the 90-120k band.
Methodology & source. Based on 5,354 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.