Mercedes SLK (2015)

Estimated running costs and MOT pass rates from 11,055 MOT tests in 2024.

Annual Cost

£3,153

£263/month

MOT Pass Rate

87%

Good

Road Tax

£790

Estimated/year

Est. Insurance

Grp 35-50

5461cc Petrol

Solid Option

87% pass rate, £3,153/year to run. 5 points above average.

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Petrol5461cc11 years old11,055 tests49k miles avg

Annual Running Costs

Fuel (Petrol, 5461cc)

~30 mpg

£1,958

Road Tax

Estimated CO2 band

£790

MOT Test

£55

Predicted Repairs

£350

Total per year£3,153

Per month£263/mo

Per week£61/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

87% MOT pass rate(Good)

0%All-model avg: 82%100%

Good reliability. Occasional issues but generally solid. That's close to the average of 82% across all models in our data.

87% of MOT tests on Mercedes SLKs from 2015 ended in a pass in 2024, when they were about 9 years old. That's based on 11,055 tests across the UK, retests included. The average mileage recorded at those tests was 48,710 miles.

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How Does It Compare?

Rank among 2015 models218th of 515(top half)

Rank among Mercedes models783rd of 1,376(bottom half)

vs average of all models+5%(82% avg)

vs 2015 models average+4%(83% avg)

vs Mercedes average+0%(87% avg)

Mileage Analysis

48,710

Average miles

66,600

Expected for age

The average 2015 Mercedes SLK had 48,710 miles on the clock at its 2024 MOT, which is below the expected 66,600 miles for a 9-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 2016 model has the highest MOT pass rate at 89%, while the 1996 model has the lowest at 76%. The 2015 scores 87%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

Mercedes SLK by Year

Year	Pass Rate	Tests	Avg Mileage
2016	89%	2,572	42,977 mi
2015	87%	11,055	48,710 mi
2014	87%	11,284	55,581 mi
2013	85%	11,106	62,322 mi
2012	84%	13,361	64,940 mi
2011	85%	5,660	61,469 mi
2010	80%	4,472	66,541 mi
2009	81%	5,347	71,532 mi
2008	80%	6,876	75,187 mi
2007	79%	7,700	77,695 mi
2006	79%	7,884	80,213 mi
2005	78%	10,305	82,791 mi
2004	78%	6,598	84,132 mi
2003	78%	3,327	85,438 mi
2002	81%	3,692	87,295 mi
2001	82%	4,005	90,848 mi
2000	79%	3,545	90,918 mi
1999	79%	4,295	87,626 mi
1998	79%	3,523	89,671 mi
1997	81%	2,190	90,802 mi
1996	76%	126	98,709 mi

Similar Cars to Consider

Land Rover Range Rover

2017 · 4999cc Petrol

£2,413/year

91%

+4%

Mercedes S-Class

2017 · 5461cc Petrol

£2,413/year

93%

+6%

Jaguar F-Type

2014 · 5000cc Petrol

£3,003/year

94%

+7%

Jaguar XK

2014 · 5000cc Petrol

£3,003/year

93%

+6%

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About the 2015 Mercedes SLK

The 2015 Mercedes SLK is a premium performance car. Our records list a 5461cc petrol engine, though engines vary between versions. 11,055 MOT tests were recorded on this model in 2024, making it one of the most commonly tested models on UK roads. Among all models from 2015, the average MOT pass rate is 83%, and this model beats that benchmark.

With an average of 48,710 miles recorded at its 2024 MOT tests, Mercedes SLK owners tend to use this car less than the typical driver.

2015 Mercedes SLK Fuel Costs

The 5461cc 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 2015 Mercedes SLK?

Total estimated annual running cost is £3,153 (£263/month), broken down as £1,958 fuel, £790 road tax, £55 MOT, and £350 predicted repairs. Repair costs are moderate, reflecting the 87% pass rate. Keeping on top of servicing will help avoid surprises.

Mercedes SLK Reliability Trend

Newer Mercedes SLKs pass their MOT more often than older ones, by 4 percentage points on average, which is mostly down to age and wear.

Buying a Used 2015 Mercedes SLK

At 11 years old, the Mercedes SLK 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 2016 model has the highest pass rate at 89%. With 11,055 MOT tests in our data, there's strong statistical confidence in these figures.

What the 2015 Mercedes SLK Fails Its MOT On

Share of the 970 MOT tests on the 2015 Mercedes SLK that failed at the first attempt in 2025, next to all cars and vans of the same age.

Tyres40%
Same age: 25% (fails on this more often)
Suspension40%
Same age: 32%
Brakes14%
Same age: 21% (fails on this less often)
Lights and electrics13%
Same age: 33% (fails on this less often)

DVSA anonymised MOT data for 2025; a test that failed on two areas counts in both. How we count it · Mercedes SLK 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 11 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.

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 2015 Mercedes SLK 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 SLK(2015)	87%	£1,958	£790	Grp 35-50	£3,153
Land Rover Range Rover(2017)	91%	£1,958	£200	Grp 35-50	£2,413-£740
Mercedes S-Class(2017)	93%	£1,958	£200	Grp 35-50	£2,413-£740
Jaguar F-Type(2014)	94%	£1,958	£790	Grp 35-50	£3,003-£150
Jaguar XK(2014)	93%	£1,958	£790	Grp 35-50	£3,003-£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 2015 Mercedes SLK

Is the 2015 Mercedes SLK reliable?

Good reliability. Occasional issues but generally solid. 87% of MOT tests on 2015 Mercedes SLKs ended in a pass, from 11,055 tests (DVSA MOT data for tests in 2024, retests included). That's 5 points above the average of 82% across all models in the same data.

How much does a 2015 Mercedes SLK cost to run?

Our estimate is £3,153 a year (£263 a month): £1,958 fuel, £790 road tax, £55 MOT and £350 predicted repairs, based on 7,400 miles a year. Insurance is not included.

What is the MOT pass rate for a 2015 Mercedes SLK?

87% of 11,055 MOT tests on the 2015 Mercedes SLK ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 218th of 515 models first registered in 2015 (top half).

Which year Mercedes SLK has the best MOT pass rate?

Of the years with at least 100 tests, the 2016 Mercedes SLK has the highest MOT pass rate at 89% and the 1996 the lowest at 76%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2015 Mercedes SLK?

The average mileage recorded at MOT tests on the 2015 Mercedes SLK is 48,710 miles, which is below the expected 66,600 miles for a 9-year-old car. This suggests lighter use than average, which generally means less wear on major components.