Mercedes Sl55 MOT Pass Rate
Overall pass rate across all manufacture years, based on 257 real MOT test results. Failure rate: 12.8%.
Data from official DVSA MOT testing records
Mercedes Sl55 MOT Reliability Overview
The Mercedes Sl55 is a rare vehicle in the UK, with 257 MOT test results recorded in our database spanning 3 manufacture years. It has an overall MOT pass rate of 87.2% and a failure rate of 12.8%, which is well above the UK average of approximately 37%.
Based on this data, the Mercedes Sl55 earns a "Excellent" reliability rating. The average Mercedes Sl55 presents for MOT with approximately 50,771 miles on the clock. Manufacture year matters: 2004 models achieve the highest pass rate at 93.5%, while 2002 models have the lowest at 79.7%. This 13.8 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes Sl55 is Suspension, affecting 8.2% of all tests. 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. The second most common issue is Tyres at 7.4%. Brakes rounds out the top three at 7.4%. 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 | Suspension | 10.1% | 26 |
| 2 | Tyres | 8.9% | 23 |
| 3 | Brakes | 8.2% | 21 |
| 4 | Lamps, Reflectors And Electrical Equipment | 5.4% | 14 |
| 5 | Driver's View Of The Road | 1.9% | 5 |
| 6 | Exhaust, Fuel And Emissions | 1.6% | 4 |
| 7 | Road Wheels | 1.6% | 4 |
| 8 | Non-component Advisories | 1.2% | 3 |
| 9 | Registration Plates And Vin | 0.8% | 2 |
| 10 | Steering | 0.8% | 2 |
| 11 | Visibility | 0.4% | 1 |
| 12 | Noise, Emissions And Leaks | 0.4% | 1 |
| 13 | Seat Belts And Supplementary Restraint Systems | 0.4% | 1 |
| 14 | Items Not Tested | 0.4% | 1 |
Failures per 10,000 Miles
avg. 50,771 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 |
|---|---|---|---|
| Suspension | 1.99 | 10.1% | 26 |
| Tyres | 1.76 | 8.9% | 23 |
| Brakes | 1.61 | 8.2% | 21 |
| Lamps & Electrical | 1.07 | 5.4% | 14 |
| Visibility | 0.46 | 2.3% | 6 |
| Emissions & Exhaust | 0.31 | 1.6% | 4 |
| Wheels | 0.31 | 1.6% | 4 |
| Non-component advisories | 0.23 | 1.2% | 3 |
| Registration Plates and VIN | 0.15 | 0.8% | 2 |
| Steering | 0.15 | 0.8% | 2 |
| Noise, emissions and leaks | 0.08 | 0.4% | 1 |
| Seat Belts | 0.08 | 0.4% | 1 |
| Items Not Tested | 0.08 | 0.4% | 1 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes Sl55 has 50,771 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 Sl55 has a mileage-adjusted failure rate of 2.52% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes Sl55 MOT Data
The Mercedes Sl55 is a rare vehicle in the UK, with 257 MOT test results recorded in our database spanning 3 manufacture years. It has an overall MOT pass rate of 87.2% and a failure rate of 12.8%, which is well above the UK average of approximately 37%.
For Mercedes Sl55 owners, these results suggest a reliable vehicle that generally passes its MOT without major issues. Focus your pre-MOT checks on suspension and tyres 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 Sl55 is likely to perform.
Suspension — 8.2% of failures
Suspension issues account for 8.2% of MOT failures on the Mercedes Sl55. 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 — 7.4% of failures
Tyres issues account for 7.4% of MOT failures on the Mercedes Sl55. 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.
Brakes — 7.4% of failures
Brakes issues account for 7.4% of MOT failures on the Mercedes Sl55. 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).
Frequently Asked Questions
What is the MOT pass rate for the Mercedes Sl55?
Based on 257 MOT tests in our database, the Mercedes Sl55 has an overall pass rate of 87.2% (12.8% fail rate).
What are the most common MOT failures on a Mercedes Sl55?
The top 3 reasons a Mercedes Sl55 fails its MOT are: 1. Suspension (8.2%), 2. Tyres (7.4%), 3. Brakes (7.4%). Check these areas before booking your MOT.
Is the Mercedes Sl55 reliable?
With a 12.8% MOT failure rate, the Sl55 is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes Sl55?
Based on failure data, focus on: Suspension (8.2%); Tyres (7.4%); Brakes (7.4%). 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.