Mercedes 320cdi MOT Pass Rate
Overall pass rate across all manufacture years, based on 129 real MOT test results. Failure rate: 30.2%.
Data from official DVSA MOT testing records
Mercedes 320cdi MOT Reliability Overview
The Mercedes 320cdi is a rare vehicle in the UK, with 129 MOT test results recorded in our database spanning 2 manufacture years. It has an overall MOT pass rate of 69.8% and a failure rate of 30.2%, which is slightly above the UK average of approximately 37%.
Based on this data, the Mercedes 320cdi earns a "Good" reliability rating. The average Mercedes 320cdi presents for MOT with approximately 84,107 miles on the clock. Manufacture year matters: 2008 models achieve the highest pass rate at 83.7%, while 2006 models have the lowest at 67.5%. This 16.2 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes 320cdi is Brakes, affecting 21.7% of all tests. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. The second most common issue is Suspension at 18.6%. Tyres rounds out the top three at 17.8%. Together, these top 3 failure categories account for a significant portion of all MOT failures for this model.
Top failures across all manufacture years combined. Individual year pages may show different top failures.
What Fails Most
Pass Rate by Manufacture Year
* High Fail Rate badge indicates an MOT pass rate below 65% (failure rate above 35%).
What Fails on This Car?
Click a category to see specific failure items.
View as table
| Rank | Failure Category | Rate (%) | Count |
|---|---|---|---|
| 1 | Brakes | 24.8% | 32 |
| 2 | Tyres | 24.0% | 31 |
| 3 | Suspension | 21.7% | 28 |
| 4 | Lamps, Reflectors And Electrical Equipment | 14.7% | 19 |
| 5 | Driver's View Of The Road | 3.9% | 5 |
| 6 | Road Wheels | 2.3% | 3 |
| 7 | Body, Chassis, Structure | 1.6% | 2 |
| 8 | Registration Plates And Vin | 1.6% | 2 |
| 9 | Steering | 0.8% | 1 |
| 10 | Noise, Emissions And Leaks | 0.8% | 1 |
Failures per 10,000 Miles
avg. 84,107 miFor every 10,000 miles driven, this shows what percentage of MOT tests fail for each category. This accounts for how far cars are actually driven, not just raw pass/fail counts.
View as table
| Category | Rate / 10K mi | Raw % | Count |
|---|---|---|---|
| Brakes | 2.95 | 24.8% | 32 |
| Tyres | 2.86 | 24.0% | 31 |
| Suspension | 2.58 | 21.7% | 28 |
| Lamps & Electrical | 1.75 | 14.7% | 19 |
| Visibility | 0.46 | 3.9% | 5 |
| Wheels | 0.28 | 2.3% | 3 |
| Body & Structure | 0.18 | 1.6% | 2 |
| Registration Plates and VIN | 0.18 | 1.6% | 2 |
| Steering | 0.09 | 0.8% | 1 |
| Noise, emissions and leaks | 0.09 | 0.8% | 1 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes 320cdi has 84,107 miles when tested for MOT.
📊 Mileage-Adjusted Failure Rate
How often this car fails MOT relative to how much it's driven — a fairer comparison than raw pass rate.
The Mercedes 320cdi has a mileage-adjusted failure rate of 3.59% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes 320cdi MOT Data
The Mercedes 320cdi is a rare vehicle in the UK, with 129 MOT test results recorded in our database spanning 2 manufacture years. It has an overall MOT pass rate of 69.8% and a failure rate of 30.2%, which is slightly above the UK average of approximately 37%.
For Mercedes 320cdi owners, these results suggest a reliable vehicle that generally passes its MOT without major issues. Focus your pre-MOT checks on brakes and suspension for the best chance of a first-time pass. Use our detailed year-by-year breakdown and failure analysis below to understand how your specific 320cdi is likely to perform.
Brakes — 21.7% of failures
Brakes issues account for 21.7% of MOT failures on the Mercedes 320cdi. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. Typical repair costs: £150–400. Pre-MOT check: Listen for squealing or grinding noises. Check brake pedal feel — if it feels spongy or goes to the floor, have the system inspected immediately. Look at brake pad thickness through the wheel spokes (minimum 3mm).
Suspension — 18.6% of failures
Suspension issues account for 18.6% of MOT failures on the Mercedes 320cdi. Suspension failures typically involve worn bushes, leaking shock absorbers, broken coil springs, and damaged suspension arms. These affect ride quality, tyre wear, and road holding. Typical repair costs: £200–500. Pre-MOT check: Look for uneven tyre wear, listen for clunking over bumps, and check if the car pulls to one side. A bouncy ride suggests worn shock absorbers. Visually inspect coil springs for cracks.
Tyres — 17.8% of failures
Tyres issues account for 17.8% of MOT failures on the Mercedes 320cdi. Tyre failures include tread depth below the legal minimum of 1.6mm, cuts, bulges, exposed cords, and incorrect tyre pressure. Tyres are one of the most common and easiest-to-prevent MOT failures. Typical repair costs: £50–200 per tyre. Pre-MOT check: Check tread depth with a 20p coin — if the outer band is visible, the tyre is too worn. Look for bulges, cuts, or embedded objects. Ensure all tyres match the recommended size and load rating.
Frequently Asked Questions
What is the MOT pass rate for the Mercedes 320cdi?
Based on 129 MOT tests in our database, the Mercedes 320cdi has an overall pass rate of 69.8% (30.2% fail rate).
What are the most common MOT failures on a Mercedes 320cdi?
The top 3 reasons a Mercedes 320cdi fails its MOT are: 1. Brakes (21.7%), 2. Suspension (18.6%), 3. Tyres (17.8%). Check these areas before booking your MOT.
Is the Mercedes 320cdi reliable?
With a 30.2% MOT failure rate, the 320cdi is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes 320cdi?
Based on failure data, focus on: Brakes (21.7%); Suspension (18.6%); Tyres (17.8%). These are the areas most likely to cause a fail. Also check all lights, tyres (minimum 1.6mm tread), and windscreen condition — these are quick wins that apply to all cars.
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.