Mercedes-Benz Clk years to avoid — 78,086 MOT tests ranked

Inspect most carefully: 2009. Strongest in the data: 2001. The ranking uses 78,086 MOT tests across 9 registration years (2023–2025) and compares each year with all UK cars of the same age. Fuel-type signal: diesels show an average 5.8-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 Clk 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	2001 Strong	108.1	+8.1 pts	74.7%	3,999
2	2002	106.1	+6.1 pts	71.7%	4,823
3	2003	104.5	+4.5 pts	69.5%	8,746
4	2005	102.8	+2.8 pts	67.3%	11,731
5	2004	102.5	+2.5 pts	66.8%	11,737
6	2006	102.4	+2.4 pts	66.8%	9,603
7	2008	101.1	+1.1 pts	66.2%	7,785
8	2007	100.9	+0.9 pts	66.0%	11,034
9	2009 Inspect	98.8	-1.2 pts	65.2%	8,628

Why 2009 rank lower

The 2009 cohort passes 65.2% of tests (-1.2 points versus same-age cars) at a median 93,910 miles, with suspension the leading failure system. This is population-level evidence, not a known-fault list: service history, engine version and the individual MOT record can outweigh the registration-year average.

How to use this before buying

Rankings describe the cohort, not the car. A cherished 2009 example beats a neglected 2001 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 (5.8 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 Clk years should I avoid?

Based on 78,086 MOT tests adjusted against cars of the same age, 2009 are the lower-scoring outliers. That is a prompt for closer inspection, not proof that every car from those years is bad.

What is the best Clk year to buy used?

2001 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 Clk reliable overall?

Across 78,086 tests, the median age-adjusted index is 102.5 (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.

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. Class 4 initial tests only; retests excluded; at least 1,500 tests per page. “Inspect” years are below both the same-age baseline and the model’s median index by at least 2 points. Association is not proof of a model-year defect. DVSA anonymised data 2023–2025, OGL v3.0.