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
About the Mercedes 300
The Mercedes 300 has been tested 3,966 times in 2026 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.
Estimated Running Costs
Based on 7,400 miles/year, current fuel prices, 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.
Mercedes 300 Guides & Articles
Petrol vs Diesel in 2026: Which Actually Costs Less to Own?
8 min read
Buying GuideCars That Lose Value Fastest: Models to Avoid for Depreciation
8 min read
Running CostsCheapest Cars to Run in 2026: Real Data from 19.8 Million MOT Tests
9 min read
Buying GuideFord Fiesta Common Problems (2026): What to Check Before Buying
13 min read
ReliabilityFord Puma Problems: 7 Issues Owners Report (2026)
13 min read
Checking a specific Mercedes 300?
Enter the reg plate to see its individual MOT history, mileage verification, and predicted costs.