2009 Mercedes-Benz Clk — MOT failures & pass rate
19,765 MOT tests on the 2009 Mercedes-Benz Clk are in this dataset, and 73.7% of them passed. Against coupes & convertibles of a similar age (20.3% fail rate), the 2009 Clk comes out 6.1pp worse. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
Suspension dominates the failure mix at 16.9% of all tests — 8.8 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are ball joint, coil spring and rigid brake pipes — ball joint alone was recorded 1,804 times.
Condition tracks the odometer closely. Failures run at 10.1% in the 0-30k band and 31.5% in the 150k+ band, a 21.4-point spread — more than double.
Split by fuel, diesel examples fail 3.2pp more often than petrol ones (28.5% vs 25.3%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 37.9% of tests without failing them.
The trend is worsening — 25.3% of tests failed in 2021 against 26.8% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 16.9% | 3,344 |
| 2 | Lighting & signalling | 8.1% | 1,600 |
| 3 | Brakes | 8.1% | 1,598 |
| 4 | Tyres | 7.1% | 1,400 |
| 5 | Visibility | 4.1% | 814 |
| 6 | Emissions & environmental | 2.4% | 480 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 1,804 |
| 2 | Coil spring | 1,542 |
| 3 | Rigid brake pipes | 868 |
| 4 | Headlamp aim | 785 |
| 5 | Tread depth | 779 |
| 6 | Pins and bushes | 581 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 37.9% | 7,484 |
| 2 | Suspension | 28.7% | 5,673 |
| 3 | Tyres | 26.4% | 5,220 |
| 4 | Lighting & signalling | 9.6% | 1,898 |
| 5 | Other defects | 8.7% | 1,726 |
| 6 | Body, structure & corrosion | 7.7% | 1,522 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 288 | 10.1% |
| 30-60k | 2,808 | 19.3% |
| 60-90k | 6,500 | 24.9% |
| 90-120k | 5,789 | 28.2% |
| 120-150k | 2,966 | 31.3% |
| 150k+ | 1,403 | 31.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 13,604 | 25.3% |
| Diesel | 6,161 | 28.5% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 4,142 | 25.3% |
| 2022 | 4,200 | 26.5% |
| 2023 | 4,034 | 26.9% |
| 2024 | 3,803 | 26.3% |
| 2025 | 3,586 | 26.8% |
What to check before buying a 2009 Clk
On a 2009 Clk, suspension is what the MOT record says goes wrong most — it appeared in 16.9% of tests. Check these areas before you commit.
- Suspension (16.9% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Lighting & signalling (8.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.1% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2009 Mercedes-Benz Clks pass their MOT?
73.7% of the 19,765 2009 Mercedes-Benz Clk MOT tests in this dataset passed — a 26.3% fail rate.
What is the most common MOT failure on a 2009 Mercedes-Benz Clk?
Suspension, recorded in 16.9% of tests, followed by lighting & signalling (8.1%).
Does the 2009 Clk get worse with mileage?
Its MOT fail rate rises from 10.1% in the 0-30k band to 31.5% in the 150k+ band.
Methodology & source. Based on 19,765 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.