Mercedes Slk 230k MOT Pass Rate
Overall pass rate across all manufacture years, based on 163,632 real MOT test results. Failure rate: 31.0%.
Data from official DVSA MOT testing records
Mercedes Slk 230k MOT Reliability Overview
The Mercedes Slk 230k is a well-known vehicle in the UK, with 163,632 MOT test results recorded in our database spanning 15 manufacture years. It has an overall MOT pass rate of 69.0% and a failure rate of 31.0%, which is slightly above the UK average of approximately 37%.
Based on this data, the Mercedes Slk 230k earns a "Good" reliability rating. The average Mercedes Slk 230k presents for MOT with approximately 76,428 miles on the clock. Manufacture year matters: 2008 models achieve the highest pass rate at 85.0%, while 1996 models have the lowest at 65.2%. This 19.8 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes Slk 230k is Lamps, Reflectors and Electrical Equipment, affecting 24.3% 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 Brakes at 22.3%. Suspension rounds out the top three at 16.5%. 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
Based on MOT data, 2002 models have the highest pass rate at 71.5%.
Based on 2020 MOT test results only — the most recent data available. "Built" = year of manufacture. Cars need their first MOT at 3 years old, so the newest cars shown are from ~3 years ago.
Bar chart showing pass rate by manufacture year from 1997 to 2003
📈 How Each Vintage Ages
Tracking how each manufacture year's MOT pass rate changes as the car ages. Showing 9 vintages — click year chips to highlight.
Multi-line chart showing how different Mercedes Slk 230k vintages degrade over time, from age 3 to 23 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 Slk 230k. The dashed red line marks when the manufacturer warranty typically expires (3 years).
Line chart showing MOT failure rate by vehicle age from 5 to 20 years, with warranty expiry marked at 3 years.
💡 What does the warranty cliff mean?
The Mercedes Slk 230k shows a relatively stable failure rate after warranty — the change of 0% is negligible. Peak failure occurs at age 17 (33.8% fail rate).
Note: pass rates may improve for very old vehicles due to survivorship bias — only well-maintained cars remain on the road.
* 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 | 35.1% | 57,570 |
| 2 | Brakes | 26.1% | 42,671 |
| 3 | Suspension | 19.0% | 31,163 |
| 4 | Tyres | 18.7% | 30,613 |
| 5 | Driver's View Of The Road | 8.3% | 13,557 |
| 6 | Exhaust, Fuel And Emissions | 5.0% | 8,249 |
| 7 | Steering | 4.1% | 6,763 |
| 8 | Registration Plates And Vin | 2.0% | 3,325 |
| 9 | Visibility | 1.3% | 2,078 |
| 10 | Noise, Emissions And Leaks | 1.2% | 1,922 |
| 11 | Non-component Advisories | 1.0% | 1,558 |
| 12 | Body, Chassis, Structure | 0.8% | 1,372 |
| 13 | Road Wheels | 0.7% | 1,160 |
| 14 | Seat Belts And Supplementary Restraint Systems | 0.7% | 1,068 |
Failures per 10,000 Miles
avg. 76,428 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 | 4.60 | 35.1% | 57,570 |
| Brakes | 3.41 | 26.1% | 42,671 |
| Suspension | 2.49 | 19.0% | 31,163 |
| Tyres | 2.45 | 18.7% | 30,613 |
| Visibility | 1.25 | 9.6% | 15,635 |
| Emissions & Exhaust | 0.66 | 5.0% | 8,249 |
| Steering | 0.54 | 4.1% | 6,763 |
| Registration Plates and VIN | 0.27 | 2.0% | 3,325 |
| Noise, emissions and leaks | 0.15 | 1.2% | 1,922 |
| Non-component advisories | 0.12 | 1.0% | 1,558 |
| Body & Structure | 0.11 | 0.8% | 1,372 |
| Wheels | 0.09 | 0.7% | 1,160 |
| Seat Belts | 0.09 | 0.7% | 1,068 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes Slk 230k has 76,428 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 Slk 230k has a mileage-adjusted failure rate of 4.06% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes Slk 230k MOT Data
The Mercedes Slk 230k is a well-known vehicle in the UK, with 163,632 MOT test results recorded in our database spanning 15 manufacture years. It has an overall MOT pass rate of 69.0% and a failure rate of 31.0%, which is slightly above the UK average of approximately 37%.
For Mercedes Slk 230k 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 brakes 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 Slk 230k is likely to perform.
Lamps, Reflectors and Electrical Equipment — 24.3% of failures
Lamps, Reflectors and Electrical Equipment issues account for 24.3% of MOT failures on the Mercedes Slk 230k. 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.
Brakes — 22.3% of failures
Brakes issues account for 22.3% of MOT failures on the Mercedes Slk 230k. 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 — 16.5% of failures
Suspension issues account for 16.5% of MOT failures on the Mercedes Slk 230k. 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.
Frequently Asked Questions
What is the MOT pass rate for the Mercedes Slk 230k?
Based on 163,632 MOT tests in our database, the Mercedes Slk 230k has an overall pass rate of 69.0% (31.0% fail rate).
What are the most common MOT failures on a Mercedes Slk 230k?
The top 3 reasons a Mercedes Slk 230k fails its MOT are: 1. Lamps, Reflectors and Electrical Equipment (24.3%), 2. Brakes (22.3%), 3. Suspension (16.5%). Check these areas before booking your MOT.
Is the Mercedes Slk 230k reliable?
With a 31.0% MOT failure rate, the Slk 230k is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes Slk 230k?
Based on failure data, focus on: Lamps, Reflectors and Electrical Equipment (24.3%); Brakes (22.3%); Suspension (16.5%). 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.