Mercedes GLC 300 AMG Line Premium 4M A (2021)
Estimated running costs and MOT pass rates from 334 MOT tests in 2024.
Annual Cost
£2,086
£174/month
MOT Pass Rate
93%
Excellent
Road Tax
£200
Standard rate/year
Est. Insurance
Grp 18-32
1991cc Hybrid
Great Choice
93% pass rate, £2,086/year to run. 11 points above average.
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Annual Running Costs
~36 mpg (petrol-engine estimate; hybrids usually use less)
Standard rate (from April 2017)
Low estimate due to excellent reliability
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. 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
Excellent reliability. Very few MOT failures. That's 11 points above the average of 82% across all models in our data. It also outperforms the Mercedes brand average of 87%.
93% of MOT tests on Mercedes GLC 300 AMG Line Premium 4M As from 2021 ended in a pass in 2024, when they were about 3 years old. That's based on 334 tests across the UK, retests included. The average mileage recorded at those tests was 27,121 miles.
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How Does It Compare?
Mileage Analysis
27,121
Average miles
22,200
Expected for age
The average 2021 Mercedes GLC 300 AMG Line Premium 4M A had 27,121 miles on the clock at its 2024 MOT, which is above the expected 22,200 miles for a 3-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?
Of the years with at least 100 tests, the 2020 model has the highest MOT pass rate at 94%, while the 2019 model has the lowest at 85%. The 2021 scores 93%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.
Mercedes GLC 300 AMG Line Premium 4M A by Year
Similar Cars to Consider
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About the 2021 Mercedes GLC 300 AMG Line Premium 4M A
The 2021 Mercedes GLC 300 AMG Line Premium 4M A is a premium car. Our records list a 1991cc hybrid engine, though engines vary between versions. 334 MOT tests were recorded on this model in 2024, making it a less common model in the UK market. Among all models from 2021, the average MOT pass rate is 92%, and this model beats that benchmark.
With an average of 27,121 miles recorded at its 2024 MOT tests, Mercedes GLC 300 AMG Line Premium 4M A owners cover more miles than the average driver.
2021 Mercedes GLC 300 AMG Line Premium 4M A Fuel Costs
The 1991cc hybrid engine offers a reasonable balance between performance and economy. Our estimate uses around 36 mpg, the figure for a petrol engine of this size, which works out to roughly £1,631 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). As a hybrid it should use less than that, and real-world fuel costs depend a lot on how much electric-only driving you do.
What does it cost to own a 2021 Mercedes GLC 300 AMG Line Premium 4M A?
Total estimated annual running cost is £2,086 (£174/month), broken down as £1,631 fuel, £200 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 GLC 300 AMG Line Premium 4M A Reliability Trend
Newer Mercedes GLC 300 AMG Line Premium 4M As pass their MOT more often than older ones, by 9 percentage points on average, which is mostly down to age and wear.
Buying a Used 2021 Mercedes GLC 300 AMG Line Premium 4M A
At 5 years old, the Mercedes GLC 300 AMG Line Premium 4M A 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 2020 model has the highest pass rate at 94%.
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.
Hybrid Battery Health
Medium riskAfter 5 years, hybrid battery capacity may have reduced. A full replacement costs £2,000-£4,000, though reconditioning is cheaper at £500-£1,500.
Inverter and Power Electronics
Low riskThe inverter converts DC to AC for the electric motor. Failures are expensive (£1,500+) but relatively rare. Listen for unusual buzzing sounds.
Regenerative Braking
Medium riskBrake discs can corrode from reduced use (the electric motor handles most braking). Surface rust is normal but deep pitting needs attention.
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 2021 Mercedes GLC 300 AMG Line Premium 4M A 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 GLC 300 AMG Line Premium 4M A(2021) | 93% | £1,631 | £200 | Grp 18-32 | £2,086 |
| Toyota Yaris(2019) | 93% | £1,398 | £200 | Grp 12-25 | £1,853-£233 |
| MINI Cooper S(2019) | 92% | £1,398 | £200 | Grp 12-25 | £1,853-£233 |
| Land Rover Range Rover Sport(2019) | 94% | £1,631 | £200 | Grp 18-32 | £2,086same |
| Toyota Prius(2019) | 94% | £1,631 | £200 | Grp 18-32 | £2,086same |
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 2021 Mercedes GLC 300 AMG Line Premium 4M A
Is the 2021 Mercedes GLC 300 AMG Line Premium 4M A reliable?
Excellent reliability. Very few MOT failures. 93% of MOT tests on 2021 Mercedes GLC 300 AMG Line Premium 4M As ended in a pass, from 334 tests (DVSA MOT data for tests in 2024, retests included). That's 11 points above the average of 82% across all models in the same data.
How much does a 2021 Mercedes GLC 300 AMG Line Premium 4M A cost to run?
Our estimate is £2,086 a year (£174 a month): £1,631 fuel, £200 road tax, £55 MOT and £200 predicted repairs, based on 7,400 miles a year. Insurance is not included.
What is the MOT pass rate for a 2021 Mercedes GLC 300 AMG Line Premium 4M A?
93% of 334 MOT tests on the 2021 Mercedes GLC 300 AMG Line Premium 4M A ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 1611th of 3,336 models first registered in 2021 (top half).
Which year Mercedes GLC 300 AMG Line Premium 4M A has the best MOT pass rate?
Of the years with at least 100 tests, the 2020 Mercedes GLC 300 AMG Line Premium 4M A has the highest MOT pass rate at 94% and the 2019 the lowest at 85%. Newer cars usually pass more often simply because they are younger and have done fewer miles.
What is the average mileage for a 2021 Mercedes GLC 300 AMG Line Premium 4M A?
The average mileage recorded at MOT tests on the 2021 Mercedes GLC 300 AMG Line Premium 4M A is 27,121 miles, which is above the expected 22,200 miles for a 3-year-old car. Higher-mileage cars often have more motorway miles, which is generally less harmful than stop-start urban driving.
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
Toyota Yaris
2019 · 1497cc Hybrid
MINI Cooper S
2019 · 1499cc Hybrid
Land Rover Range Rover Sport
2019 · 1997cc Hybrid
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