Mercedes Sl320 MOT Pass Rate
Overall pass rate across all manufacture years, based on 151 real MOT test results. Failure rate: 18.5%.
Data from official DVSA MOT testing records
Mercedes Sl320 MOT Reliability Overview
The Mercedes Sl320 is a rare vehicle in the UK, with 151 MOT test results recorded in our database spanning 3 manufacture years. It has an overall MOT pass rate of 81.5% and a failure rate of 18.5%, which is well above the UK average of approximately 37%.
Based on this data, the Mercedes Sl320 earns a "Excellent" reliability rating. The average Mercedes Sl320 presents for MOT with approximately 75,286 miles on the clock. Manufacture year matters: 1998 models achieve the highest pass rate at 90.7%, while 1997 models have the lowest at 70.6%. This 20.1 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes Sl320 is Lamps, Reflectors and Electrical Equipment, affecting 19.2% of all tests. Lighting failures cover all external lights: headlights, tail lights, brake lights, indicators, fog lights, and reflectors. A single blown bulb will cause an MOT fail. This is one of the most preventable failure categories. The second most common issue is Suspension at 11.3%. Tyres rounds out the top three at 10.6%. 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 | Lamps, Reflectors And Electrical Equipment | 21.2% | 32 |
| 2 | Tyres | 13.9% | 21 |
| 3 | Suspension | 11.3% | 17 |
| 4 | Brakes | 10.6% | 16 |
| 5 | Steering | 5.3% | 8 |
| 6 | Exhaust, Fuel And Emissions | 4.0% | 6 |
| 7 | Driver's View Of The Road | 4.0% | 6 |
| 8 | Non-component Advisories | 2.0% | 3 |
| 9 | Registration Plates And Vin | 2.0% | 3 |
| 10 | Body, Structure And General Items | 0.7% | 1 |
| 11 | Seat Belts And Supplementary Restraint Systems | 0.7% | 1 |
Failures per 10,000 Miles
avg. 75,286 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 |
|---|---|---|---|
| Lamps & Electrical | 2.82 | 21.2% | 32 |
| Tyres | 1.85 | 13.9% | 21 |
| Suspension | 1.50 | 11.3% | 17 |
| Brakes | 1.41 | 10.6% | 16 |
| Steering | 0.70 | 5.3% | 8 |
| Emissions & Exhaust | 0.53 | 4.0% | 6 |
| Visibility | 0.53 | 4.0% | 6 |
| Non-component advisories | 0.26 | 2.0% | 3 |
| Registration Plates and VIN | 0.26 | 2.0% | 3 |
| Body & Structure | 0.09 | 0.7% | 1 |
| Seat Belts | 0.09 | 0.7% | 1 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes Sl320 has 75,286 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 Sl320 has a mileage-adjusted failure rate of 2.46% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes Sl320 MOT Data
The Mercedes Sl320 is a rare vehicle in the UK, with 151 MOT test results recorded in our database spanning 3 manufacture years. It has an overall MOT pass rate of 81.5% and a failure rate of 18.5%, which is well above the UK average of approximately 37%.
For Mercedes Sl320 owners, these results suggest a reliable vehicle that generally passes its MOT without major issues. Focus your pre-MOT checks on lamps, reflectors and electrical equipment 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 Sl320 is likely to perform.
Lamps, Reflectors and Electrical Equipment — 19.2% of failures
Lamps, Reflectors and Electrical Equipment issues account for 19.2% of MOT failures on the Mercedes Sl320. Lighting failures cover all external lights: headlights, tail lights, brake lights, indicators, fog lights, and reflectors. A single blown bulb will cause an MOT fail. This is one of the most preventable failure categories. Typical repair costs: £5–50. Pre-MOT check: Walk around the car and check every light — headlights (dipped and main beam), side lights, tail lights, brake lights, indicators, hazard lights, reverse light, rear fog light, and number plate lights. Replace any blown bulbs before the test.
Suspension — 11.3% of failures
Suspension issues account for 11.3% of MOT failures on the Mercedes Sl320. 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 — 10.6% of failures
Tyres issues account for 10.6% of MOT failures on the Mercedes Sl320. 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 Sl320?
Based on 151 MOT tests in our database, the Mercedes Sl320 has an overall pass rate of 81.5% (18.5% fail rate).
What are the most common MOT failures on a Mercedes Sl320?
The top 3 reasons a Mercedes Sl320 fails its MOT are: 1. Lamps, Reflectors and Electrical Equipment (19.2%), 2. Suspension (11.3%), 3. Tyres (10.6%). Check these areas before booking your MOT.
Is the Mercedes Sl320 reliable?
With a 18.5% MOT failure rate, the Sl320 is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes Sl320?
Based on failure data, focus on: Lamps, Reflectors and Electrical Equipment (19.2%); Suspension (11.3%); Tyres (10.6%). 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.