Mercedes CLK (2003)
Estimated running costs and MOT pass rates from 6,287 MOT tests in 2024.
Annual Cost
£2,958
£247/month
MOT Pass Rate
78%
Average
Road Tax
£445
Estimated/year
Est. Insurance
Grp 25-38
2295cc Petrol
Check Carefully
78% pass rate, £2,958/year to run. Close to the average across all models.
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Annual Running Costs
~30 mpg
Estimated CO2 band
Estimates based on 7,400 miles/year (UK average), petrol at 174.57p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included.
Reliability Verdict
Average reliability. Expect some repairs as it ages. That's close to the average of 82% across all models in our data. It falls below the Mercedes brand average of 87%.
78% of MOT tests on Mercedes CLKs from 2003 ended in a pass in 2024, when they were about 21 years old. That's based on 6,287 tests across the UK, retests included. The average mileage recorded at those tests was 105,487 miles.
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How Does It Compare?
Mileage Analysis
105,487
Average miles
155,400
Expected for age
The average 2003 Mercedes CLK had 105,487 miles on the clock at its 2024 MOT, which is below the expected 155,400 miles for a 21-year-old car. This suggests lighter use than average, which generally means less wear on major components.
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Best Year to Buy?
Of the years with at least 100 tests, the 2000 model has the highest MOT pass rate at 81%, while the 1997 model has the lowest at 75%. The 2003 scores 78%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.
Mercedes CLK by Year
| Year | Pass Rate | Tests | Avg Mileage | |
|---|---|---|---|---|
| 2012 | 90% | 30 | 61,131 mi | |
| 2011 | 75% | 40 | 64,021 mi | |
| 2010 | 77% | 152 | 92,126 mi | |
| 2009 | 76% | 6,353 | 97,542 mi | |
| 2008 | 75% | 5,758 | 104,878 mi | |
| 2007 | 76% | 8,003 | 106,765 mi | |
| 2006 | 76% | 7,045 | 106,273 mi | |
| 2005 | 76% | 8,463 | 107,835 mi | |
| 2004 | 76% | 8,352 | 105,633 mi | |
| 2003 | 78% | 6,287 | 105,487 mi | |
| 2002 | 78% | 3,392 | 106,379 mi | |
| 2001 | 79% | 2,542 | 103,971 mi | |
| 2000 | 81% | 2,099 | 102,251 mi | |
| 1999 | 78% | 2,485 | 103,421 mi | |
| 1998 | 77% | 800 | 102,449 mi | |
| 1997 | 75% | 138 | 86,436 mi |
Similar Cars to Consider
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About the 2003 Mercedes CLK
The 2003 Mercedes CLK is a premium car. Our records list a 2295cc petrol engine, though engines vary between versions. 6,287 MOT tests were recorded on this model in 2024, making it a reasonably common sight on UK roads. Among all models from 2003, the average MOT pass rate is 72%, and this model beats that benchmark.
With an average of 105,487 miles recorded at its 2024 MOT tests, Mercedes CLK owners tend to use this car less than the typical driver.
2003 Mercedes CLK Fuel Costs
The 2295cc petrol engine offers a reasonable balance between performance and economy. Expect around 30 mpg in mixed driving, which works out to roughly £1,958 per year with petrol at 174.57p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year).
What does it cost to own a 2003 Mercedes CLK?
Total estimated annual running cost is £2,958 (£247/month), broken down as £1,958 fuel, £445 road tax, £55 MOT, and £500 predicted repairs. Repair costs are moderate, reflecting the 78% pass rate. Keeping on top of servicing will help avoid surprises.
Mercedes CLK Reliability Trend
The Mercedes CLK has maintained consistent MOT pass rates across model years, varying by only 2 percentage points.
Buying a Used 2003 Mercedes CLK
At 23 years old, the Mercedes CLK is firmly in budget territory. Purchase prices are low, but check for rust, worn suspension bushes, and electrical gremlins. A full service history is especially valuable at this age. If you're flexible on year, the 2000 model has the highest pass rate at 81%. With 6,287 MOT tests in our data, there's strong statistical confidence in these figures.
What the 2003 Mercedes CLK Fails Its MOT On
Share of the 827 MOT tests on the 2003 Mercedes CLK that failed at the first attempt in 2025, next to all cars and vans of the same age.
- Suspension46%
Same age: 38%
- Lights and electrics42%
Same age: 50%
- Brakes23%
Same age: 31% (fails on this less often)
- Tyres19%
Same age: 14% (fails on this more often)
DVSA anonymised MOT data for 2025; a test that failed on two areas counts in both. How we count it · Mercedes CLK reliability, common problems and years to avoid
Common Issues to Watch For
These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.
Timing Chain / Belt
Watch outAt 23 years old, check whether the timing belt has been replaced (typically due every 5-7 years or 60,000-100,000 miles). A snapped belt can destroy the engine.
Oil Consumption
Medium riskLarger petrol engines can develop higher oil consumption as they age. Check the oil level and look for blue smoke from the exhaust.
Rust and Corrosion
Watch outAt 10+ years, check wheel arches, sills, subframe, and brake lines for rust. Structural corrosion is an MOT failure. Prevention is far cheaper than repair.
Suspension Bushings
Watch outRubber suspension bushes harden and crack with age, causing knocking noises and vague handling. A full refresh costs £300-£800 depending on the car.
Clutch Wear
Watch outWith an average of 105k miles, clutch replacement may be due (typical lifespan 60,000-100,000 miles). Budget £400-£800 for a new clutch kit.
Brake Discs and Pads
Medium riskHigh-mileage cars often need brake disc replacement, not just pads. A full set of discs and pads costs £200-£500 per axle.
Service History
Low riskAlways request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.
Running Costs Compared
How the 2003 Mercedes CLK stacks up against similar cars for estimated annual running costs, insurance group, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Est. Ins. Group | Total/yr |
|---|---|---|---|---|---|
| Mercedes CLK(2003) | 78% | £1,958 | £445 | Grp 25-38 | £2,958 |
| Renault Clio(2005) | 67% | £1,631 | £325 | Grp 18-32 | £2,711-£247 |
| Mercedes C(2005) | 73% | £1,631 | £325 | Grp 18-32 | £2,511-£447 |
| Honda CR-V(2005) | 70% | £1,631 | £325 | Grp 18-32 | £2,511-£447 |
| Land Rover Freelander(2005) | 69% | £1,631 | £325 | Grp 18-32 | £2,711-£247 |
Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.
Questions about the 2003 Mercedes CLK
Is the 2003 Mercedes CLK reliable?
Average reliability. Expect some repairs as it ages. 78% of MOT tests on 2003 Mercedes CLKs ended in a pass, from 6,287 tests (DVSA MOT data for tests in 2024, retests included). That's 4 points below the average of 82% across all models in the same data.
How much does a 2003 Mercedes CLK cost to run?
Our estimate is £2,958 a year (£247 a month): £1,958 fuel, £445 road tax, £55 MOT and £500 predicted repairs, based on 7,400 miles a year. Insurance is not included.
What is the MOT pass rate for a 2003 Mercedes CLK?
78% of 6,287 MOT tests on the 2003 Mercedes CLK ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 113th of 429 models first registered in 2003 (top half).
Which year Mercedes CLK has the best MOT pass rate?
Of the years with at least 100 tests, the 2000 Mercedes CLK has the highest MOT pass rate at 81% and the 1997 the lowest at 75%. Newer cars usually pass more often simply because they are younger and have done fewer miles.
What is the average mileage for a 2003 Mercedes CLK?
The average mileage recorded at MOT tests on the 2003 Mercedes CLK is 105,487 miles, which is below the expected 155,400 miles for a 21-year-old car. This suggests lighter use than average, which generally means less wear on major components.
Related Mercedes Models
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Renault Clio
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