Mercedes CLS (2020)

Estimated running costs and MOT pass rates from 708 MOT tests in 2024.

Annual Cost

£2,281

£190/month

MOT Pass Rate

85%

Good

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 30-42

2925cc Diesel

Solid Option

85% pass rate, £2,281/year to run. Close to the average across all models.

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Diesel2925cc6 years old708 tests34k miles avg

Annual Running Costs

Fuel (Diesel, 2925cc)

~40 mpg

£1,676

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

£350

Total per year£2,281

Per month£190/mo

Per week£44/wk

Estimates based on 7,400 miles/year (UK average), diesel at 199.33p 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. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).

Reliability Verdict

85% 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.

85% of MOT tests on Mercedes CLSs from 2020 ended in a pass in 2024, when they were about 4 years old. That's based on 708 tests across the UK, retests included. The average mileage recorded at those tests was 33,613 miles.

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How Does It Compare?

Rank among 2020 models2321st of 2,554(bottom 10%)

Rank among Mercedes models886th of 1,376(bottom half)

vs average of all models+3%(82% avg)

vs 2020 models average-7%(92% avg)

vs Mercedes average-2%(87% avg)

Mileage Analysis

33,613

Average miles

29,600

Expected for age

The average 2020 Mercedes CLS had 33,613 miles on the clock at its 2024 MOT, which is in line with the expected 29,600 miles for a 4-year-old car, suggesting normal everyday use.

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Best Year to Buy?

Of the years with at least 100 tests, the 2019 model has the highest MOT pass rate at 90%, while the 2009 model has the lowest at 78%. The 2020 scores 85%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

Mercedes CLS by Year

Year	Pass Rate	Tests	Avg Mileage
2021	90%	149	25,838 mi
2020	85%	708	33,613 mi
2019	90%	2,938	42,687 mi
2018	89%	2,552	49,336 mi
2017	87%	3,475	61,581 mi
2016	87%	4,786	69,870 mi
2015	87%	6,871	81,130 mi
2014	85%	4,192	86,883 mi
2013	83%	7,096	95,825 mi
2012	83%	2,664	97,844 mi
2011	82%	2,675	100,976 mi
2010	79%	2,428	110,846 mi
2009	78%	2,541	114,393 mi
2008	78%	2,982	122,863 mi
2007	78%	3,915	122,774 mi
2006	79%	3,184	117,836 mi
2005	81%	1,944	108,622 mi

Similar Cars to Consider

Mercedes E

2019 · 2925cc Diesel

£2,131/year

90%

+5%

Mercedes GLC

2018 · 2987cc Diesel

£2,131/year

91%

+6%

Ford Ranger

2019 · 3198cc Diesel

£2,281/year

87%

+2%

Land Rover Range Rover Velar

2018 · 2993cc Diesel

£2,131/year

91%

+6%

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About the 2020 Mercedes CLS

The 2020 Mercedes CLS is a premium performance car. Our records list a 2925cc diesel engine, though engines vary between versions. 708 MOT tests were recorded on this model in 2024, making it a less common model in the UK market. It sits in the bottom 10% of 2020 models for MOT pass rate.

With an average of 33,613 miles recorded at its 2024 MOT tests, Mercedes CLS owners drive about as much as the UK average.

2020 Mercedes CLS Fuel Costs

The 2925cc diesel engine is on the larger side, so fuel won't be this car's strong point. Expect around 40 mpg in mixed driving, which works out to roughly £1,676 per year with diesel at 199.33p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year). Diesel cars of this age should have their DPF (diesel particulate filter) checked, as replacements can be costly.

What does it cost to own a 2020 Mercedes CLS?

Total estimated annual running cost is £2,281 (£190/month), broken down as £1,676 fuel, £200 road tax, £55 MOT, and £350 predicted repairs. Repair costs are moderate, reflecting the 85% pass rate. Keeping on top of servicing will help avoid surprises.

Mercedes CLS Reliability Trend

Newer Mercedes CLSs pass their MOT more often than older ones, by 7 percentage points on average, which is mostly down to age and wear.

Buying a Used 2020 Mercedes CLS

At 6 years old, the Mercedes CLS offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost. If you're flexible on year, the 2019 model has the highest pass rate at 90%.

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.

DPF (Diesel Particulate Filter)

Watch out

Short journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.

Turbo Wear

Medium risk

Diesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.

AdBlue System

Medium risk

Post-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.

EGR Valve

Watch out

Exhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.

Dual Mass Flywheel

Medium risk

Larger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.

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 2020 Mercedes CLS 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 CLS(2020)	85%	£1,676	£200	Grp 30-42	£2,281
Mercedes E(2019)	90%	£1,676	£200	Grp 30-42	£2,131-£150
Mercedes GLC(2018)	91%	£1,676	£200	Grp 30-42	£2,131-£150
Ford Ranger(2019)	87%	£1,676	£200	Grp 35-50	£2,281same
Land Rover Range Rover Velar(2018)	91%	£1,676	£200	Grp 30-42	£2,131-£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 2020 Mercedes CLS

Is the 2020 Mercedes CLS reliable?

Good reliability. Occasional issues but generally solid. 85% of MOT tests on 2020 Mercedes CLSs ended in a pass, from 708 tests (DVSA MOT data for tests in 2024, retests included). That's 3 points above the average of 82% across all models in the same data.

How much does a 2020 Mercedes CLS cost to run?

Our estimate is £2,281 a year (£190 a month): £1,676 fuel, £200 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 2020 Mercedes CLS?

85% of 708 MOT tests on the 2020 Mercedes CLS ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 2321st of 2,554 models first registered in 2020 (bottom 10%).

Which year Mercedes CLS has the best MOT pass rate?

Of the years with at least 100 tests, the 2019 Mercedes CLS has the highest MOT pass rate at 90% and the 2009 the lowest at 78%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2020 Mercedes CLS?

The average mileage recorded at MOT tests on the 2020 Mercedes CLS is 33,613 miles, which is in line with the expected 29,600 miles for a 4-year-old car, suggesting normal everyday use.