Mercedes Sl 55 MOT Pass Rate
Overall pass rate across all manufacture years, based on 18,743 real MOT test results. Failure rate: 18.8%.
Data from official DVSA MOT testing records
Mercedes Sl 55 MOT Reliability Overview
The Mercedes Sl 55 is a relatively common sight on UK roads, with 18,743 MOT test results recorded in our database spanning 7 manufacture years. It has an overall MOT pass rate of 81.2% and a failure rate of 18.8%, which is well above the UK average of approximately 37%.
Based on this data, the Mercedes Sl 55 earns a "Excellent" reliability rating. The average Mercedes Sl 55 presents for MOT with approximately 52,060 miles on the clock. Manufacture year matters: 2006 models achieve the highest pass rate at 86.4%, while 2002 models have the lowest at 79.4%. This 7.0 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes Sl 55 is Suspension, affecting 12.6% 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 11.4%. Brakes rounds out the top three at 10.2%. 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
Best Year to Buy
📈 How Each Vintage Ages
Tracking how each manufacture year's MOT pass rate changes as the car ages. Showing 4 vintages — click year chips to highlight.
Multi-line chart showing how different Mercedes Sl 55 vintages degrade over time, from age 3 to 20 years.
Only vintages with 100+ tests in at least 3 different test years are shown. Fleet average is the UK-wide pass rate for all cars at each age.
📉 How Age Affects Reliability
MOT failure rate by vehicle age for the Mercedes Sl 55. The dashed red line marks when the manufacturer warranty typically expires (3 years).
Line chart showing MOT failure rate by vehicle age from 3 to 18 years, with warranty expiry marked at 3 years.
💡 What does the warranty cliff mean?
The Mercedes Sl 55 sees a significant jump in MOT failures after the warranty period. Failure rate increases by 51% once warranty cover ends. Budget for increased maintenance costs from year 4 onwards. Peak failure occurs at age 10 (22.1% fail rate).
Note: pass rates may improve for very old vehicles due to survivorship bias — only well-maintained cars remain on the road.
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 | 14.7% | 2,748 |
| 2 | Tyres | 14.2% | 2,662 |
| 3 | Brakes | 11.9% | 2,231 |
| 4 | Lamps, Reflectors And Electrical Equipment | 6.4% | 1,203 |
| 5 | Registration Plates And Vin | 3.1% | 590 |
| 6 | Driver's View Of The Road | 2.3% | 427 |
| 7 | Road Wheels | 1.8% | 341 |
| 8 | Exhaust, Fuel And Emissions | 1.6% | 294 |
| 9 | Steering | 1.4% | 271 |
| 10 | Seat Belts And Supplementary Restraint Systems | 0.9% | 161 |
| 11 | Noise, Emissions And Leaks | 0.4% | 75 |
| 12 | Non-component Advisories | 0.3% | 55 |
| 13 | Visibility | 0.2% | 43 |
| 14 | Identification Of The Vehicle | 0.2% | 42 |
Failures per 10,000 Miles
avg. 52,060 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 | 2.82 | 14.7% | 2,748 |
| Tyres | 2.73 | 14.2% | 2,662 |
| Brakes | 2.29 | 11.9% | 2,231 |
| Lamps & Electrical | 1.23 | 6.4% | 1,203 |
| Registration Plates and VIN | 0.60 | 3.1% | 590 |
| Visibility | 0.48 | 2.5% | 470 |
| Wheels | 0.35 | 1.8% | 341 |
| Emissions & Exhaust | 0.30 | 1.6% | 294 |
| Steering | 0.28 | 1.4% | 271 |
| Seat Belts | 0.16 | 0.9% | 161 |
| Noise, emissions and leaks | 0.08 | 0.4% | 75 |
| Non-component advisories | 0.06 | 0.3% | 55 |
| Identification of the vehicle | 0.04 | 0.2% | 42 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes Sl 55 has 52,060 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 Sl 55 has a mileage-adjusted failure rate of 3.61% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes Sl 55 MOT Data
The Mercedes Sl 55 is a relatively common sight on UK roads, with 18,743 MOT test results recorded in our database spanning 7 manufacture years. It has an overall MOT pass rate of 81.2% and a failure rate of 18.8%, which is well above the UK average of approximately 37%.
For Mercedes Sl 55 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 Sl 55 is likely to perform.
Suspension — 12.6% of failures
Suspension issues account for 12.6% of MOT failures on the Mercedes Sl 55. 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 — 11.4% of failures
Tyres issues account for 11.4% of MOT failures on the Mercedes Sl 55. 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 — 10.2% of failures
Brakes issues account for 10.2% of MOT failures on the Mercedes Sl 55. 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 Sl 55?
Based on 18,743 MOT tests in our database, the Mercedes Sl 55 has an overall pass rate of 81.2% (18.8% fail rate).
What are the most common MOT failures on a Mercedes Sl 55?
The top 3 reasons a Mercedes Sl 55 fails its MOT are: 1. Suspension (12.6%), 2. Tyres (11.4%), 3. Brakes (10.2%). Check these areas before booking your MOT.
Is the Mercedes Sl 55 reliable?
With a 18.8% MOT failure rate, the Sl 55 is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes Sl 55?
Based on failure data, focus on: Suspension (12.6%); Tyres (11.4%); Brakes (10.2%). 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.