BMW 520i — MOT pass rate & failures
The BMW 520i passed 78.8% of its 21,430 MOT tests, covering model years 1981–2025. That is 5.4 percentage points worse than the 15.7% fail rate across all BMW 5 Series versions, so the 520i is a weaker pick within the range. Failures concentrate in lighting & signalling, suspension and brakes.
What the MOT record shows
At component level the recurring items are headlamp aim, washers and catalyst emissions — headlamp aim alone was recorded 1,062 times.
A 150k+ example is materially riskier than a 0-30k one: 27.3% versus 8.7%.
Advisories point at the next bill rather than this one: brakes was flagged on 27.1% of tests without failing them.
The trend is improving — the fail rate fell from 24.3% in 2021 to 16.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
| Year | Tests | Pass rate | Fail rate |
|---|---|---|---|
| 1983 | 44 | 77.3% | 22.7% |
| 1984 | 61 | 73.8% | 26.2% |
| 1985 | 99 | 74.8% | 25.3% |
| 1986 | 107 | 84.1% | 15.9% |
| 1987 | 195 | 82.0% | 17.9% |
| 1988 | 153 | 79.7% | 20.3% |
| 1989 | 102 | 77.5% | 22.6% |
| 1990 | 80 | 81.3% | 18.8% |
| 1991 | 117 | 84.6% | 15.4% |
| 1992 | 169 | 73.4% | 26.6% |
| 1993 | 260 | 76.5% | 23.5% |
| 1994 | 359 | 75.5% | 24.5% |
| 1995 | 660 | 74.6% | 25.4% |
| 1996 | 286 | 74.1% | 25.9% |
| 1997 | 400 | 70.3% | 29.8% |
| 1998 | 702 | 72.2% | 27.8% |
| 1999 | 1,034 | 71.0% | 29.0% |
| 2000 | 1,013 | 73.6% | 26.4% |
| 2001 | 1,698 | 75.7% | 24.3% |
| 2002 | 2,300 | 74.0% | 26.0% |
| 2003 | 2,759 | 74.2% | 25.8% |
| 2004 | 1,890 | 75.2% | 24.8% |
| 2005 | 342 | 77.8% | 22.2% |
| 2006 | 113 | 73.5% | 26.6% |
| 2007 | 118 | 83.0% | 17.0% |
| 2008 | 98 | 83.7% | 16.3% |
| 2009 | 119 | 79.0% | 21.0% |
| 2010 | 125 | 80.0% | 20.0% |
| 2011 | 204 | 80.4% | 19.6% |
| 2012 | 458 | 83.6% | 16.4% |
| 2013 | 340 | 83.8% | 16.2% |
| 2014 | 624 | 88.9% | 11.1% |
| 2015 | 1,088 | 89.3% | 10.7% |
| 2016 | 568 | 91.0% | 9.0% |
| 2017 | 95 | 87.4% | 12.6% |
| 2018 | 205 | 93.7% | 6.3% |
| 2019 | 141 | 90.8% | 9.2% |
| 2020 | 455 | 91.9% | 8.1% |
| 2021 | 1,139 | 92.1% | 7.9% |
| 2022 | 639 | 89.2% | 10.8% |
| 2023 | 39 | 94.9% | 5.1% |
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 9.5% | 2,045 |
| 2 | Suspension | 9.2% | 1,971 |
| 3 | Brakes | 7.9% | 1,702 |
| 4 | Tyres | 5.1% | 1,094 |
| 5 | Visibility | 4.9% | 1,054 |
| 6 | Emissions & environmental | 3.9% | 842 |
| 7 | Seat belts & restraints | 2.9% | 618 |
| 8 | Steering | 2.5% | 543 |
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 | 1,062 |
| 2 | Washers | 764 |
| 3 | Catalyst emissions | 719 |
| 4 | Rbt (sp) | 670 |
| 5 | Headlamp | 655 |
| 6 | Rigid brake pipes | 642 |
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 | 27.1% | 5,801 |
| 2 | Suspension | 23.1% | 4,950 |
| 3 | Tyres | 22.6% | 4,841 |
| 4 | Emissions & environmental | 19.7% | 4,211 |
| 5 | Other defects | 13.6% | 2,904 |
| 6 | Lighting & signalling | 10.5% | 2,255 |
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 | 2,163 | 8.7% |
| 30-60k | 3,082 | 12.1% |
| 60-90k | 3,571 | 19.3% |
| 90-120k | 4,641 | 23.9% |
| 120-150k | 4,071 | 26.8% |
| 150k+ | 3,628 | 27.3% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 4,982 | 24.3% |
| 2022 | 4,322 | 22.9% |
| 2023 | 3,955 | 21.9% |
| 2024 | 3,955 | 19.5% |
| 2025 | 4,216 | 16.6% |
What to check before buying a BMW 520i
Focus on the areas it most often fails on — and remember MOT data covers testable defects only, not engine or gearbox health.
- Lighting & signalling (9.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (9.2% 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 (7.9% 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 reliable is the BMW 520i at MOT time?
78.8% of the 21,430 BMW 520i MOT tests in this dataset passed — a 21.2% fail rate, worse than the 15.7% average across all 5 Series versions.
What is the most common MOT failure on a BMW 520i?
Lighting & signalling, recorded in 9.5% of tests, followed by suspension (9.2%).
Does the 520i get worse with mileage?
Its MOT fail rate rises from 8.7% in the 0-30k band to 27.3% in the 150k+ band.
Methodology & source. Based on 21,430 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.