2004 Mercedes-Benz SLK MOT pass rate: 70.1% (8,890 tests)
Is the 2004 SLK getting worse?
Pass rate of 2004-registered cars across recent test years:
| Test year | Pass rate | |
|---|---|---|
| 2023 | 69.5% +5.6 vs same-age |
|
| 2024 | 69.9% +5.8 vs same-age |
|
| 2025 | 71.1% +5.8 vs same-age |
The raw rate normally falls as cars age. The “vs same-age” figure compares this cohort with all UK cars registered in the same year, so normal ageing is not mistaken for a bad model year.
What fails on a 2004 SLK
| # | System | Defects recorded | Share |
|---|---|---|---|
| 1 | Suspension | 2,011 | 28.0% |
| 2 | Lamps, reflectors and electrical equipment | 1,330 | 18.5% |
| 3 | Brakes | 1,257 | 17.5% |
| 4 | Tyres | 688 | 9.6% |
| 5 | Noise, emissions and leaks | 563 | 7.8% |
| 6 | Steering | 525 | 7.3% |
All SLK years compared
| Registration year | Tests | Pass rate | Vs same-age | Median mileage |
|---|---|---|---|---|
| 2001 | 6,218 | 76.8% | +10.1 pts | 87,028 |
| 2002 | 5,528 | 77.7% | +11.9 pts | 84,096 |
| 2003 | 5,058 | 73.6% | +8.5 pts | 81,064 |
| 2004 (this page) | 8,890 | 70.1% | +5.7 pts | 81,784 |
| 2005 | 13,925 | 71.2% | +6.7 pts | 79,516 |
| 2006 | 10,788 | 71.6% | +7.2 pts | 77,638 |
| 2007 | 10,293 | 71.2% | +6.1 pts | 72,692 |
| 2008 | 9,411 | 71.4% | +6.3 pts | 71,853 |
| 2009 | 7,333 | 72.2% | +5.8 pts | 66,664 |
| 2010 | 6,106 | 73.6% | +6.2 pts | 62,311 |
| 2011 | 7,403 | 78.6% | +9.4 pts | 57,773 |
| 2012 | 16,341 | 77.3% | +6.1 pts | 60,294 |
| 2013 | 13,440 | 77.6% | +4.3 pts | 58,930 |
| 2014 | 14,281 | 80.7% | +4.8 pts | 51,701 |
| 2015 | 14,302 | 83.2% | +4.5 pts | 45,175 |
| 2016 | 3,688 | 85.4% | +4.1 pts | 39,182 |
Weighing up which year to buy? See the full ranking: Mercedes-Benz SLK years to avoid.
- Free MOT history checkThe exact car’s failures, advisories and mileage trail — sellers can’t edit it
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FAQs
Is a 2004 Mercedes-Benz SLK reliable?
2004-registered examples passed 70.1% of their MOT tests (8,890 tests, 2023–2025), +5.7 points versus all UK cars registered in the same year. At roughly 22 years old with a median 81,784 miles, condition now varies car by car — always check the individual MOT history.
What mileage is too high for a 2004 SLK?
The median tested example shows 81,784 miles. Anything far beyond that isn't automatically bad — a motorway-mile car with consistent service records often beats a low-mileage school-run car — but price accordingly and scrutinise the mileage trail for gaps or drops.
Source: DVSA Anonymised MOT tests and results, 2023–2025 extracts (96 million Class 4 initial tests; retests excluded). Only vehicles old enough for a routine first MOT are included. Age-adjusted figures compare the model-year cohort with all vehicles of the same registration year tested in the same calendar year. Contains public sector information licensed under OGL v3.0.