Mercedes CLK (2004)

Estimated running costs and MOT pass rates from 8,352 MOT tests in 2024.

Annual Cost

£3,303

£275/month

MOT Pass Rate

76%

Average

Road Tax

£790

Estimated/year

Est. Insurance

Grp 35-50

4966cc Petrol

Check Carefully

76% pass rate, £3,303/year to run. 6 points below average.

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Petrol4966cc22 years old8,352 tests106k miles avg

Annual Running Costs

Fuel (Petrol, 4966cc)

~30 mpg

£1,958

Road Tax

Estimated CO2 band

£790

MOT Test

£55

Predicted Repairs

£500

Total per year£3,303

Per month£275/mo

Per week£64/wk

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

76% MOT pass rate(Average)

0%All-model avg: 82%100%

Average reliability. Expect some repairs as it ages. That's 6 points below the average of 82% across all models in our data. It falls below the Mercedes brand average of 87%.

76% of MOT tests on Mercedes CLKs from 2004 ended in a pass in 2024, when they were about 20 years old. That's based on 8,352 tests across the UK, retests included. The average mileage recorded at those tests was 105,633 miles.

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How Does It Compare?

Rank among 2004 models172nd of 470(top half)

Rank among Mercedes models1199th of 1,376(bottom 13%)

vs average of all models-6%(82% avg)

vs 2004 models average+4%(72% avg)

vs Mercedes average-11%(87% avg)

Mileage Analysis

105,633

Average miles

148,000

Expected for age

The average 2004 Mercedes CLK had 105,633 miles on the clock at its 2024 MOT, which is below the expected 148,000 miles for a 20-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 2004 scores 76%. 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

BMW X5

2005 · 4799cc Petrol

£3,303/year

77%

+1%

Mercedes SL

2003 · 4966cc Petrol

£3,153/year

86%

+10%

Rover 75

2004 · 4601cc Petrol

£3,503/year

69%

-7%

Mercedes ML

2006 · 4966cc Petrol

£3,153/year

80%

+4%

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About the 2004 Mercedes CLK

The 2004 Mercedes CLK is a premium performance car. Our records list a 4966cc petrol engine, though engines vary between versions. 8,352 MOT tests were recorded on this model in 2024, making it a reasonably common sight on UK roads. Among all models from 2004, the average MOT pass rate is 72%, and this model beats that benchmark.

With an average of 105,633 miles recorded at its 2024 MOT tests, Mercedes CLK owners tend to use this car less than the typical driver.

2004 Mercedes CLK Fuel Costs

The 4966cc petrol engine is on the larger side, so fuel won't be this car's strong point. 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 2004 Mercedes CLK?

Total estimated annual running cost is £3,303 (£275/month), broken down as £1,958 fuel, £790 road tax, £55 MOT, and £500 predicted repairs. Repair costs are moderate, reflecting the 76% 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 2004 Mercedes CLK

At 22 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 8,352 MOT tests in our data, there's strong statistical confidence in these figures.

What the 2004 Mercedes CLK Fails Its MOT On

Share of the 1,267 MOT tests on the 2004 Mercedes CLK that failed at the first attempt in 2025, next to all cars and vans of the same age.

Suspension51%
Same age: 39% (fails on this more often)
Lights and electrics40%
Same age: 50%
Brakes27%
Same age: 30%
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 out

At 22 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 risk

Larger 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 out

At 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 out

Rubber 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 out

With an average of 106k 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 risk

High-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 risk

Always 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 2004 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(2004)	76%	£1,958	£790	Grp 35-50	£3,303
BMW X5(2005)	77%	£1,958	£790	Grp 35-50	£3,303same
Mercedes SL(2003)	86%	£1,958	£790	Grp 35-50	£3,153-£150
Rover 75(2004)	69%	£1,958	£790	Grp 35-50	£3,503+£200
Mercedes ML(2006)	80%	£1,958	£790	Grp 35-50	£3,153-£150

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 2004 Mercedes CLK

Is the 2004 Mercedes CLK reliable?

Average reliability. Expect some repairs as it ages. 76% of MOT tests on 2004 Mercedes CLKs ended in a pass, from 8,352 tests (DVSA MOT data for tests in 2024, retests included). That's 6 points below the average of 82% across all models in the same data.

How much does a 2004 Mercedes CLK cost to run?

Our estimate is £3,303 a year (£275 a month): £1,958 fuel, £790 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 2004 Mercedes CLK?

76% of 8,352 MOT tests on the 2004 Mercedes CLK ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 172nd of 470 models first registered in 2004 (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 2004 Mercedes CLK?

The average mileage recorded at MOT tests on the 2004 Mercedes CLK is 105,633 miles, which is below the expected 148,000 miles for a 20-year-old car. This suggests lighter use than average, which generally means less wear on major components.