MERCEDES S 350 L GRAND ED EXECUTIVE D A (2020)
Running costs, reliability data, and common problems from 1,168 real MOT tests.
Annual Cost
£1,695
£141/month
MOT Pass Rate
93%
Excellent
Road Tax
£195
Flat rate/year
Insurance
Grp 30-42
2925cc Diesel
Great Choice
93% pass rate, £1695/year to run. 11 points above average.
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Annual Running Costs
~40 mpg
Flat rate (post-2017)
Low estimate due to excellent reliability
Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT data. Insurance not included.
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Reliability Verdict
Excellent reliability. Very few MOT failures. That's 11 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.
At 6 years old, 93% of MERCEDES S 350 L GRAND ED EXECUTIVE D As from 2020 passed their MOT first time in 2026. That's based on 1,168 tests across the UK. The average mileage at this age is 53,736 miles.
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How Does It Compare?
Mileage Analysis
53,736
Average miles
44,400
Expected for age
The average 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A has 53,736 miles on the clock, which is above the expected 44,400 miles for a 6-year-old car. Higher-mileage cars often have more motorway miles, which is generally less harmful than stop-start urban driving.
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Best Year to Buy?
The most reliable year is the 2021 model with a 95% MOT pass rate, while the 2020 model has the lowest at 93%. Consider a different year if reliability is a priority.
MERCEDES S 350 L GRAND ED EXECUTIVE D A by Year
Similar Cars to Consider
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About the 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A
The 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A is a large car with a 2925cc diesel engine. 1,168 of these vehicles were MOT tested in 2026, making it a reasonably common sight on UK roads. Among all cars from 2020, the average MOT pass rate is 92%, and this model beats that benchmark.
With an average of 53,736 miles at 6 years old, MERCEDES S 350 L GRAND ED EXECUTIVE D A owners cover more miles than the average driver.
2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A 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 £1,245 per year at current diesel prices of 148p per litre (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 S 350 L GRAND ED EXECUTIVE D A?
Total estimated annual running cost is £1,695 (£141/month), broken down as £1245 fuel, £195 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 93% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
MERCEDES S 350 L GRAND ED EXECUTIVE D A Reliability Trend
The MERCEDES S 350 L GRAND ED EXECUTIVE D A has maintained consistent MOT pass rates across model years, varying by only 1 percentage points.
Buying a Used 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A
At 6 years old, the MERCEDES S 350 L GRAND ED EXECUTIVE D A offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost.
Common Issues to Watch For
Based on the 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A's fuel type, age, and engine size, these are the most likely problem areas to check.
DPF (Diesel Particulate Filter)
Watch outShort journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.
Turbo Wear
Medium riskDiesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.
AdBlue System
Medium riskPost-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.
EGR Valve
Watch outExhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.
Dual Mass Flywheel
Medium riskLarger 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 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 2020 MERCEDES S 350 L GRAND ED EXECUTIVE D A stacks up against similar cars for annual running costs, insurance, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Insurance | Total/yr |
|---|---|---|---|---|---|
| MERCEDES S 350 L GRAND ED EXECUTIVE D A(2020) | 93% | £1245 | £195 | Grp 30-42 | £1695 |
| MERCEDES E(2019) | 90% | £1245 | £190 | Grp 30-42 | £1690-£5 |
| MERCEDES GLC(2018) | 91% | £1245 | £190 | Grp 30-42 | £1690-£5 |
| FORD RANGER(2019) | 87% | £1245 | £190 | Grp 35-50 | £1840+£145 |
| LAND ROVER RANGE ROVER VELAR(2018) | 91% | £1245 | £190 | Grp 30-42 | £1690-£5 |
Estimates based on 7,400 miles/year, current fuel prices, and MOT data. Insurance groups are indicative. Actual costs vary by driver, location, and usage.
Related Mercedes Models
Explore other Mercedes cars or similar models in the same category.
MERCEDES A
2019 · 1461cc Diesel
MERCEDES C
2017 · 1991cc Hybrid
MERCEDES A-CLASS
2017 · 1461cc Diesel
MERCEDES E
2019 · 2925cc Diesel
MERCEDES GLC
2018 · 2987cc Diesel
FORD RANGER
2019 · 3198cc Diesel
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