Most Reliable Mercedes Models: Real MOT Data Analysis
We analysed 5,891 real UK MOT tests to reveal which Mercedes models pass most often, which years to buy, and which to avoid entirely.
5,891 MOT tests analysed
Real DVSA data covering every Mercedes model from 2000-2023
Key Findings
Most Reliable Model
Insufficient data
N/A
Best Single Year
Insufficient data
N/A
Mercedes vs National Average
72.7% vs 71.5%
+1.2% above average
Durability Champion
N/A
N/A
Mercedes has built its reputation on reliability, but does the data back it up? We analysed 5,891 real MOT tests from the DVSA database to find out exactly which Mercedes models live up to the hype and which ones fall short.
This isn't survey data or owner opinions. These are actual pass/fail results from UK garages, covering every Mercedes model sold in the UK from 2000 to 2023.
How Mercedes Compares to Rivals
Mercedes ranks #39 out of 75 manufacturers with a 72.7% average MOT pass rate. That's above the national average of 71.5%:
| Manufacturer | Pass Rate | Rank | Tests Analysed |
|---|---|---|---|
| Toyota | 74.0% | #31 | 1,606,300 |
| Mercedes | 72.7% | #39 | 5,891 |
| Volkswagen | 72.2% | #43 | 2,967,545 |
| Nissan | 68.7% | #50 | 1,612,552 |
| Ford | 68.5% | #51 | 4,432,652 |
| Vauxhall | 65.4% | #59 | 3,038,498 |
The verdict: Toyota maintains a lead among competitors, while Mercedes sits at #39. However, newer Mercedes models significantly outperform this average.
Best Mercedes Models by MOT Pass Rate
Looking at overall reliability across all years, here's how Mercedes's core models rank against the 71.5% national average:
| Model | Pass Rate | vs National (71.5%) | Tests | Years |
|---|
Mercedes Hybrids vs Petrol vs Diesel
Mercedes's fuel type comparison shows clear differences in reliability:
| Fuel Type | Average Pass Rate | vs National | Tests |
|---|---|---|---|
| Diesel | 72.2% | +0.7% | 302 |
What Goes Wrong on Mercedess?
When Mercedess fail MOTs, these are the most common causes:
| Failure Category | Total Failures |
|---|---|
| 1. Suspension | 32 |
| 2. Lamps, reflectors and electrical equipment | 27 |
| 3. Tyres | 23 |
| 4. Noise, emissions and leaks | 17 |
| 5. Body, chassis, structure | 10 |
| 6. Brakes | 7 |
| 7. Visibility | 4 |
Pre-MOT checklist for Mercedes owners:
- Inspect suspension bushes and anti-roll bar links
- Check all bulbs (number plate lights are commonly missed)
- Ensure tyres meet 1.6mm tread requirement
- Check exhaust system for leaks and emissions
Frequently Asked Questions
Our Buying Recommendations
Best If Buying Nearly New
2019-2023 models with highest early pass rates
- Limited data for recent models
Note: Long-term durability not yet proven for these newer models
Best If Buying Used (Proven)
11+ years of proven durability data
- Limited proven durability data available
Mercedes Models to Avoid (Proven Poor)
Proven below average at 11+ years - not just old, genuinely problematic
- No major proven reliability concerns
About This Data
This analysis uses real MOT test results from the DVSA database, covering 5,891 tests on Mercedes vehicles between 2000 and 2023.
Year-Adjusted Scoring (v2.1): In year-by-year breakdowns, each vehicle is compared against the national average for vehicles of the same model year. This removes the natural bias where newer cars pass more often, allowing fair comparisons across eras.
Evidence-Tiered Durability: We separate "proven durability" (vehicles tested at 11+ years old) from "early performers" (3-6 years old). Only vehicles with proven long-term data are used for durability claims. Age-band comparisons use weighted national averages.
Minimum thresholds: 500 tests for proven durability rankings, 1,000 tests for early performer rankings. Pass rates are calculated as first-time passes, excluding retests.
The overall national average MOT pass rate is 71.51% based on 32.3 million tests across all manufacturers. Year-specific averages range from ~59% (2009 vehicles) to ~88% (2020 vehicles).
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