Petrol Mercedes-Benz 300: MOT pass rate

81.9% of petrol Mercedes-Benz 300s pass the MOT first time, measured across 2,254 DVSA tests on that fuel type alone. Average mileage at test was 107,424.

Petrol against the other Mercedes-Benz 300 versions

Why the fuel type changes the number

Petrol cars avoid the DPF and emissions failures that catch diesels, and usually fail on the same consumables as any other car.

On the Mercedes-Benz 300 specifically, petrol is the strongest at 81.9%, and this petrol version sits 1 points above the 80.9% model average.

What it means if you are buying one

The petrol Mercedes-Benz 300 is the stronger side of this model on MOT data. Still judge the individual car, but the fuel type is a mild point in its favour. 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 petrol Mercedes-Benz 300 had covered 107,424 miles at test, against 147,671 for the diesel. That is above average and into the range where cambelts and water pumps are due if they have not already been done, so ask for the service history rather than take the mileage on trust.

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 Mercedes-Benz 300 page separate age from fuel if you want to isolate one.

Most common MOT failures on a petrol Mercedes-Benz 300

1. Emissions levels exceed default limits, 2.6% of tests (7.41x the national rate for this defect)
2. Body, cab or chassis excessively corroded at a mounting point, 1% of tests (4.39x the national rate for this defect)
3. An obligatory rear fog lamp missing, or a front or rear fog lamp inoperative or in the case of a multiple light source more than 1/2 not functioning, 1.1% of tests (2.48x the national rate for this defect)
4. A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 1.6% of tests (2.4x the national rate for this defect)
5. The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired, 2.1% of tests (2.27x the national rate for this defect)
6. Steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, 1.3% of tests (1.7x the national rate for this defect)
7. The aim of a headlamp is not within limits laid down in the requirements, 3.8% of tests (1.62x the national rate for this defect)
8. Significant brake effort recorded with no brake applied indicating a binding brake, 1.7% of tests (1.6x the national rate for this defect)
9. Windscreen washers not working or not providing sufficient fluid to clear the windscreen, 2.3% of tests (1.37x the national rate for this defect)
10. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 2.3% of tests (1.26x the national rate for this defect)

From 2,288 DVSA-tracked petrol Mercedes-Benz 300 tests, 2024, split out from the Mercedes-Benz 300's other fuel types. DVSA testers marked 2.46% 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 petrol Mercedes-Benz 300

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

1. A wheel bearing with excessive play, 3.7% of tests (5.72x the national rate for this defect)
2. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 18.8% of tests (3.37x the national rate for this defect)
3. A brake hose ferrule excessively corroded, 3.9% of tests (3.06x the national rate for this defect)
4. Vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced, 3.7% of tests (2.99x the national rate for this defect)
5. The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired, 4% of tests (2.65x the national rate for this defect), also fails
6. Brake pipe damaged or excessively corroded, 16.3% of tests (2.64x the national rate for this defect)
7. A spring or spring component fractured or seriously weakened, 9.7% of tests (2.04x the national rate for this defect)
8. Exhaust system leaking or insecure, 5.8% of tests (2.04x the national rate for this defect)
9. Significant brake effort recorded with no brake applied indicating a binding brake, 3.4% of tests (1.68x the national rate for this defect), also fails
10. A tyre seriously damaged, 13% of tests

From 2,288 DVSA-tracked petrol Mercedes-Benz 300 tests, 2024.

Other Mercedes-Benz 300 fuel types

• Diesel Mercedes-Benz 300 - 76.1%

All Mercedes-Benz 300 MOT data · Every model