Diesel Mercedes-Benz Viano: MOT pass rate
70.9% of diesel Mercedes-Benz Vianos pass the MOT first time, measured across 4,855 DVSA tests on that fuel type alone. Average mileage at test was 156,497.
Diesel against the other Mercedes-Benz Viano versions
| Fuel | Pass rate | Tests |
|---|---|---|
| Diesel | 70.9% | 4,855 |
| Petrol | 75% | 535 |
| All Mercedes-Benz Viano | 71.3% | 5,395 |
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 Mercedes-Benz Viano specifically, petrol is the strongest at 75%, and this diesel version sits 0.4 points below the 71.3% 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 Mercedes-Benz Viano had covered 156,497 miles at test, against 81,176 for the petrol. That is very high mileage. Clutches, dual-mass flywheels and head gaskets have usually been through at least one repair by this point, so ask for evidence rather than assume the car is original everywhere.
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 Viano page separate age from fuel if you want to isolate one.
Most common MOT failures on a diesel Mercedes-Benz Viano
- Parking brake efficiency less than 50% of the required value, 2.8% of tests (7.63x the national rate for this defect)
- A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 4.5% of tests (6.89x the national rate for this defect)
- An SRS malfunction indicator lamp (MIL) indicates a system malfunction, 2.6% of tests (6.35x the national rate for this defect)
- Parking brake inoperative on one side, 2.5% of tests (4.18x the national rate for this defect)
- Parking brake efficiency below minimum requirement, 4.5% of tests (3.47x the national rate for this defect)
- Exhaust system leaking or insecure, 2.7% of tests (2.64x the national rate for this defect)
- 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, 2.4% of tests (2.55x the national rate for this defect)
- Significant brake effort recorded with no brake applied indicating a binding brake, 2.6% of tests (2.5x the national rate for this defect)
- A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 3.4% of tests (1.83x the national rate for this defect)
- A tyre cords visible or damaged, 2.8% of tests (1.68x the national rate for this defect)
From 4,897 DVSA-tracked diesel Mercedes-Benz Viano tests, 2024, split out from the Mercedes-Benz Viano's other fuel types. DVSA testers marked 5% 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 Mercedes-Benz Viano
Flagged but doesn't fail the car, a different list from the failures above.
- A shock absorber bush excessively worn, 3.3% of tests (6.98x the national rate for this defect)
- Lamp emitted colour, position or intensity not in accordance with the requirements, 5.4% of tests (3.92x the national rate for this defect)
- Vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced, 4.4% of tests (3.55x the national rate for this defect)
- 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, 4.1% of tests (2.73x the national rate for this defect), also fails
- Brake pipe damaged or excessively corroded, 15.9% of tests (2.57x the national rate for this defect)
- Exhaust system leaking or insecure, 7% of tests (2.45x the national rate for this defect), also fails
- Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 11.9% of tests (2.14x the national rate for this defect)
- Significant brake effort recorded with no brake applied indicating a binding brake, 3.6% of tests (1.78x the national rate for this defect), also fails
- A suspension pin, bush or joint excessively worn, 18.3% of tests (1.37x the national rate for this defect)
- Tyre tread depth not in accordance with the requirements, 33.7% of tests (1.26x the national rate for this defect)
From 4,897 DVSA-tracked diesel Mercedes-Benz Viano tests, 2024.