Mercedes 300
Reliability, estimated running costs, and MOT data across 5 model years from 3,966 MOT tests in 2024.
Avg Pass Rate
83%
Total Tests
3,966
Highest Pass Rate
1990 (84%)
Years Covered
5
About the Mercedes 300
The Mercedes 300 was MOT tested 3,966 times in 2024 (DVSA data, retests included) across 5 model years (1990 to 1994), with an average pass rate of 83%. That's slightly above the average of 82% across all models in our data. Our records list diesel and petrol versions.
Best and Worst Years
Of the years with at least 100 tests, the 1990 model has the highest pass rate at 84% from 947 tests. The 1991 model has the lowest at 81%. With just a 3 point gap, pass rates are similar across these years. Newer cars usually pass more often simply because they are younger.
Reliability Trend
The Mercedes 300 has maintained consistent MOT pass rates across model years, varying by only 0 percentage points.
Mileage Across Years
The oldest model in our data (1990) averages 126,597 miles, while the newest (1994) averages 120,492 miles. Older models have covered serious mileage, so suspension and drivetrain wear are worth checking.
Compared to the Mercedes brand average of 87%, the 300 is 4 points lower, placing it among the less reliable Mercedes models.
Estimated Running Costs
Based on 7,400 miles/year, average pump prices of 174.57p petrol and 199.33p diesel (GOV.UK weekly road fuel prices, week of 19 October 2026), and MOT pass rate data. Insurance not included.
Full 1994 detailsHow reliable is the Mercedes 300?
Mercedes 300 by Year
Click any year to see detailed running costs, reliability data, and comparisons with similar cars.
Questions about the Mercedes 300
Is the Mercedes 300 reliable?
Across its 5 model years in our data (1990 to 1994), the Mercedes 300 averages an 83% MOT pass rate, from 3,966 tests (DVSA MOT data for tests in 2024, retests included). That's 1 point above the average of 82% across all models in the same data. The 1990 model has the highest pass rate of the years with at least 100 tests, at 84%.
Which year Mercedes 300 has the best MOT pass rate?
Of the years with at least 100 tests, the 1990 Mercedes 300 has the highest MOT pass rate at 84%, while the 1991 model has the lowest at 81%, a 3 point gap. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.
Are newer Mercedes 300s more reliable?
The Mercedes 300 has maintained consistent MOT pass rates across model years, varying by only 0 percentage points.
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