MERCEDES SLC (2020)
Running costs, reliability data, and common problems from 169 real MOT tests.
Annual Cost
£2,042
£170/month
MOT Pass Rate
94%
Excellent
Road Tax
£195
Flat rate/year
Insurance
Grp 30-42
2996cc Petrol
Great Choice
94% pass rate, £2042/year to run. 12 points above average.
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Annual Running Costs
~30 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 12 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.
At 6 years old, 94% of MERCEDES SLCs from 2020 passed their MOT first time in 2026. That's based on 169 tests across the UK. The average mileage at this age is 20,514 miles.
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How Does It Compare?
Mileage Analysis
20,514
Average miles
44,400
Expected for age
The average 2020 MERCEDES SLC has 20,514 miles on the clock, which is significantly below the expected 44,400 miles for a 6-year-old car. Low-mileage examples may have spent time sitting unused, so check for issues like corroded brakes or perished rubber seals.
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Best Year to Buy?
The most reliable year is the 2021 model with a 98% MOT pass rate, while the 2016 model has the lowest at 89%. The 2020 sits between the two at 94%.
MERCEDES SLC by Year
Similar Cars to Consider
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About the 2020 MERCEDES SLC
The 2020 MERCEDES SLC is a large car with a 2996cc petrol engine. 169 of these vehicles were MOT tested in 2026, making it a rare model 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 20,514 miles at 6 years old, MERCEDES SLC owners tend to use this car less than the typical driver. Very low mileage could mean the car has been garaged or used only for short trips, which can cause its own issues like battery drain and moisture buildup.
2020 MERCEDES SLC Fuel Costs
The 2996cc 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 £1,592 per year at current petrol prices of 142p per litre (based on 7,400 miles per year).
What does it cost to own a 2020 MERCEDES SLC?
Total estimated annual running cost is £2,042 (£170/month), broken down as £1592 fuel, £195 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 94% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
MERCEDES SLC Reliability Trend
Newer MERCEDES SLCs show better MOT pass rates than older ones, with an average improvement of 5 percentage points.
Buying a Used 2020 MERCEDES SLC
At 6 years old, the MERCEDES SLC 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 2021 model has the highest pass rate at 98%.
Common Issues to Watch For
Based on the 2020 MERCEDES SLC's fuel type, age, and engine size, these are the most likely problem areas to check.
Timing Chain / Belt
Watch outAt 6 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
Low riskLarger petrol engines can develop higher oil consumption as they age. Check the oil level and look for blue smoke from the exhaust.
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 SLC stacks up against similar cars for annual running costs, insurance, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Insurance | Total/yr |
|---|---|---|---|---|---|
| MERCEDES SLC(2020) | 94% | £1592 | £195 | Grp 30-42 | £2042 |
| BMW 5 SERIES(2018) | 91% | £1592 | £190 | Grp 30-42 | £2037-£5 |
| LAND ROVER RANGE ROVER SPORT(2018) | 93% | £1592 | £190 | Grp 30-42 | £2037-£5 |
| BMW X3(2019) | 92% | £1592 | £190 | Grp 30-42 | £2037-£5 |
| MERCEDES GLC(2019) | 93% | £1592 | £190 | Grp 30-42 | £2037-£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
BMW 5 SERIES
2018 · 2998cc Petrol
LAND ROVER RANGE ROVER SPORT
2018 · 2995cc Petrol
BMW X3
2019 · 2998cc Petrol
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