Diesel BMW 520: MOT pass rate

81% of diesel BMW 520s pass the MOT first time, measured across 74,207 DVSA tests on that fuel type alone. Average mileage at test was 119,694.

Diesel against the other BMW 520 versions

Why the fuel type changes the number

Diesels carry DPFs, EGR valves and stricter smoke limits, so emissions and exhaust faults account for failures petrol cars never see.

On the BMW 520 specifically, diesel is the strongest at 81%, and this diesel version sits 0.3 points above the 80.7% model average.

What it means if you are buying one

There is little to choose between fuel types on this model, so decide on running costs and mileage rather than MOT record. Buying a damaged one? run it through the analyzer, check the exact car, decode the VIN and check the mileage before you bid.

Mileage is part of the answer

The average diesel BMW 520 had covered 119,694 miles at test, against 108,032 for the petrol. That is high mileage, so timing belts, clutches, suspension bushes and corrosion are the items worth budgeting for rather than the MOT itself.

Fuel type and mileage are tangled together: diesels are usually bought by higher-mileage drivers, so some of any gap between fuels is the miles rather than the engine. The per-year figures on the BMW 520 page separate age from fuel if you want to isolate one.

Most common MOT failures on a diesel BMW 520

1. A wheel with a loose or missing wheel nut, bolt or stud, 1% of tests (3.3x the national rate for this defect)
2. A tyre cords visible or damaged, 2.6% of tests (1.54x the national rate for this defect)
3. Tyre tread depth not in accordance with the requirements, 4.3% of tests (1.33x the national rate for this defect)
4. A spring or spring component fractured or seriously weakened, 3% of tests (1.31x the national rate for this defect)
5. A shock absorber damaged to the extent that it does not function or showing signs of severe leakage, 1.2% of tests (1.26x the national rate for this defect)
6. A suspension pin, bush or joint excessively worn, 2.8% of tests
7. A tyre seriously damaged, 2.5% of tests
8. A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 2.1% of tests
9. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 1.6% of tests
10. a brake lining or pad worn below 1.5mm, 1.5% of tests

From 74,543 DVSA-tracked diesel BMW 520 tests, 2024, split out from the BMW 520's other fuel types. DVSA testers marked 6.92% of these flagged defects as "dangerous", against 5.11% nationally. See which fuel type fails on the most dangerous defects nationally for how that compares across the whole fleet.

Most common MOT advisories on a diesel BMW 520

Flagged but doesn't fail the car, a different list from the failures above.

1. A flexible brake hose excessively damaged, deteriorated, chafed, twisted or stretched, 2.1% of tests (3.81x the national rate for this defect)
2. Tyre tread depth not in accordance with the requirements, 34.2% of tests (1.28x the national rate for this defect), also fails
3. Brake disc or drum significantly and obviously worn, 3.8% of tests (1.19x the national rate for this defect)
4. A suspension pin, bush or joint excessively worn, 11.8% of tests, also fails
5. Brake disc or drum excessively weakened, insecure or fractured, 10.9% of tests
6. a brake lining or pad worn below 1.5mm, 9.9% of tests, also fails
7. A tyre seriously damaged, 6.6% of tests, also fails
8. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 5.8% of tests
9. A shock absorber damaged to the extent that it does not function or showing signs of severe leakage, 3% of tests, also fails
10. Number plate inscription missing or illegible, 2.7% of tests

From 74,543 DVSA-tracked diesel BMW 520 tests, 2024.

Other BMW 520 fuel types

• Petrol BMW 520 - 73.6%

All BMW 520 MOT data · Every model