Mercedes 300
Reliability, running costs, and MOT data across 5 years from 3,966 real MOT tests.
Avg Pass Rate
83%
Total Tests
3,966
Best Year
1990 (84%)
Years Covered
5
How reliable is the Mercedes 300?
Mercedes 300 by Year
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About the Mercedes 300
The Mercedes 300 has been tested 3,966 times in 2024 MOT data across 5 model years (1990 to 1994), with an average pass rate of 83%. That's slightly above the national average of 82%. Available as diesel and petrol.
Best and Worst Years
The 1990 model is the most reliable with a 84% pass rate from 947 tests. The 1991 model has the lowest at 81%. With just a 3 point spread, the 300 is consistently reliable regardless of year.
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.
Click any year in the table above to see detailed running costs, individual reliability data, and comparisons with similar cars.