Mercedes-Benz SLK years to avoid — 153,005 MOT tests ranked

Last updated 16 August 2026 · OBDCode UK editorial

No clear negative outlier after correcting for age. Strongest in the data: 2002. The ranking uses 153,005 MOT test records across 16 qualifying registration-year cohorts in the 2023–2025 DVSA test extracts and compares each cohort with all UK cars of the same age. Counts are test records, not unique vehicles. Same-vehicle follow-up for common certificate lines on this model is further down: how often the same item failed the next year, and how often the car was not tested again. Fuel-type signal: diesels show an average 5.9-point pass-rate deficit on this model. That may reflect mileage and use as well as the car itself, so inspect DPF and emissions history rather than treating fuel type as a verdict.

Every SLK year, ranked

The age-adjusted MOT index sets 100 as the pass rate of all UK cars registered in the same year and tested in the same calendar year. Higher is better. This prevents an old car being labelled a “bad year” simply because it is old.

Rank	Year	Index	Vs same-age	Pass rate	Tests
1	2002 Strong	111.9	+11.9 pts	77.7%	5,528
2	2001	110.1	+10.1 pts	76.8%	6,218
3	2011	109.4	+9.4 pts	78.6%	7,403
4	2003	108.5	+8.5 pts	73.6%	5,058
5	2006	107.2	+7.2 pts	71.6%	10,788
6	2005	106.7	+6.7 pts	71.2%	13,925
7	2008	106.3	+6.3 pts	71.4%	9,411
8	2010	106.2	+6.2 pts	73.6%	6,106
9	2012	106.1	+6.1 pts	77.3%	16,341
10	2007	106.1	+6.1 pts	71.2%	10,293
11	2009	105.8	+5.8 pts	72.2%	7,333
12	2004	105.7	+5.7 pts	70.1%	8,890
13	2014	104.8	+4.8 pts	80.7%	14,281
14	2015	104.5	+4.5 pts	83.2%	14,302
15	2013	104.3	+4.3 pts	77.6%	13,440
16	2016	104.1	+4.1 pts	85.4%	3,688

What happened next on this model

Year rankings are age-adjusted pass rates. The figures below are a same-vehicle follow-up for certificate lines that appear often enough on this model (at least 200 cars). They are not a repair quote and they do not isolate a turbo, DSG, or clutch part.

Ball joint has slight play — 926 cars · 16.5% failed the same item the next year · 14.1% were not tested again
Service brake performance binding but not excessively — 230 cars · 7.4% failed the same item the next year · 15.2% were not tested again
Shock absorbers has light misting of oil — 457 cars · 6.8% failed the same item the next year · 8.5% were not tested again
Condition has a cut but not deep enough to reach the ply or cords — 618 cars · 5.0% failed the same item the next year · 6.0% were not tested again
Service brake performance fluctuating, but not excessively — 290 cars · 4.5% failed the same item the next year · 12.8% were not tested again

National rankings for the not-retested gap: cars not tested again. Repair-hold rates: repairs that did not hold.

How to use this before buying

Rankings describe the cohort, not the car. A cherished older example beats a neglected 2002 one — always run the specific reg through the free MOT history check.
Read the advisories. Repeated notes for the same component across years mean the owner has been ignoring it. Decode them in our advisory library.
Fuel matters on this model. The diesel deficit (5.9 points) usually traces to DPF and emissions kit on low-mileage use — check for P2463-type soot codes on the test drive.
Scan before you pay. A 2-minute OBD scan reveals stored faults the dashboard hides — see our scanner guide.

FAQs

Which SLK years should I avoid?

No year is a clear negative outlier after correcting for age, so buy on condition and history rather than year.

What is the best SLK year to buy used?

2002 lead the age-adjusted MOT ranking. The score compares each registration year with all UK cars of the same age; the specific car's history and condition still take priority.

Is the SLK reliable overall?

Across 153,005 tests, the median age-adjusted index is 106.2 (100 equals the pass rate of all cars registered in the same year). Use the spread between years as one signal, then check the individual registration.

What data is required before a years-to-avoid guide is published?

We publish a guide only when a model has at least five registration-year cohorts old enough for a routine first MOT, each based on at least 1,500 Class 4 initial MOT tests pooled across the stated DVSA extract years, and at least 60,000 tests across those cohorts. From the models that pass those gates, this release includes the 220 models with the largest pooled samples. Retests are excluded.

How are the Strong and Inspect labels assigned?

Strong considers only the two highest-ranked registration-year cohorts and labels either one that is within 1.5 index points of the best. Inspect considers only the three lowest-ranked cohorts and labels a year only when its index is no higher than 100 and at least 2 points below the model median. Counts are MOT test records, not unique vehicles.

Methodology: index = 100 + the model-year cohort’s MOT pass-rate difference versus all UK vehicles registered in the same year and tested in the same calendar year. Pass rate uses DVSA result codes (P + PRS) ÷ (P + PRS + F): passes and passes after rectification at the test divided by those outcomes plus failures. Class 4 initial-test records only; retests excluded; at least 1,500 records per registration-year cohort. “Strong” considers the top two cohorts within 1.5 index points of the best. “Inspect” considers only the bottom three cohorts, then requires an index no higher than 100 and at least 2 points below the model median. Counts are test records, not unique vehicles. Association is not proof of a model-year defect. Source: DVSA Anonymised MOT tests and results, 2023–2025 extracts. Contains public sector information licensed under the Open Government Licence v3.0.