Mercedes-Benz 300: MOT pass rate and reliability data

The Mercedes-Benz 300 passes its MOT first time more often than the average UK car, by 3 percentage points. These figures come from the DVSA's full year of anonymised MOT results, covering 2,828 individual Mercedes-Benz 300 tests. Nothing here is an estimate or a survey.

The numbers

First-time pass rate79.7%
UK national average76.7%
Difference+3 points
Tests analysed2,828
Average mileage at test113,799 miles
Average year of manufacture1990
Reliability rank1,450 of 2,005 models

What this means if you are buying one

A 79.7% first-time pass rate means roughly 20 in every 100 Mercedes-Benz 300s presented for MOT fail on the first attempt. That is better than average, so a well-kept example is a reasonably safe used buy. The average Mercedes-Benz 300 tested had covered 113,799 miles and was built around 1990.

What this means at salvage auction

Pass rate is a proxy for what a car costs to keep on the road. On a Mercedes-Benz 300 bought as a repairable salvage, the mechanical side is less likely to spring surprises, so your repair estimate should hold up reasonably well.

Before you bid: run the lot through the analyzer, check the car's own record, check the mileage, decode the VIN, and if it carries a marker use the write-off value calculator. Or compare it against another model.

Looking at a specific Mercedes-Benz 300 rather than the model in general? The free check covers its MOT and mileage history, and the full HPI report confirms the insurance write-off category, outstanding finance and whether it is recorded stolen, from licensed data for 5 credits. Already own one that has been damaged? Work out whether fixing it beats selling it with the repair or scrap calculator, and see what damaged Mercedes-Benz 300s actually sold for at UK salvage auction.

Most common MOT failures on a Mercedes-Benz 300

  1. Emissions levels exceed default limits, 1.7% of tests (5.68x the national rate for this defect)
  2. 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% of tests (2.91x the national rate for this defect)
  3. 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% of tests (2.44x 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, 1.1% of tests (2.31x the national rate for this defect)
  5. Steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc, 1.2% of tests (2.16x the national rate for this defect)
  6. Significant brake effort recorded with no brake applied indicating a binding brake, 1.5% of tests (1.94x the national rate for this defect)
  7. The aim of a headlamp is not within limits laid down in the requirements, 2.8% of tests (1.61x the national rate for this defect)
  8. Windscreen washers not working or not providing sufficient fluid to clear the windscreen, 1.8% of tests (1.42x the national rate for this defect)
  9. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 1.7% of tests (1.29x the national rate for this defect)
  10. Exhaust system leaking or insecure, 1% of tests (1.26x the national rate for this defect)

From 7,537 DVSA-tracked Mercedes-Benz 300 tests, 2024. DVSA testers marked 2.84% of these flagged Mercedes-Benz 300 defects as "dangerous", meaning the tester judged the car unsafe to drive away, against 4.97% nationally.

Mercedes-Benz 300 pass rate by model year

Pass rates fall steadily as cars age, so the model year matters as much as the model. First-time pass rate for each Mercedes-Benz 300 year:

Mercedes-Benz 300 by fuel type

Diesel and petrol versions of the same car fail on different things, so the fuel type moves the number:

Other Mercedes-Benz models

Models with a similar pass rate

If this car is a salvage or write-off

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Mercedes-Benz 300 MOT pass rate badge: 79.7%

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All 2,005 models ranked by MOT pass rate