Mercedes G-Class (2021)

Estimated running costs and MOT pass rates from 65 MOT tests in 2024.

Annual Cost

£2,152

£179/month

MOT Pass Rate

78%

Average

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 18-32

1950cc Diesel

Check Carefully

78% pass rate, £2,152/year to run. Close to the average across all models.

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Diesel1950cc5 years old65 tests30k miles avg

Annual Running Costs

Fuel (Diesel, 1950cc)

~48 mpg

£1,397

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

£500

Total per year£2,152

Per month£179/mo

Per week£41/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

78% MOT pass rate(Average)

0%All-model avg: 82%100%

Average reliability. Expect some repairs as it ages. That's close to the average of 82% across all models in our data. It falls below the Mercedes brand average of 87%.

78% of MOT tests on Mercedes G-Classs from 2021 ended in a pass in 2024, when they were about 3 years old. That's based on 65 tests across the UK, retests included. The average mileage recorded at those tests was 30,190 miles.

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How Does It Compare?

Rank among 2021 models3300th of 3,336(bottom 2%)

Rank among Mercedes models1162nd of 1,376(bottom 16%)

vs average of all models-4%(82% avg)

vs 2021 models average-14%(92% avg)

vs Mercedes average-9%(87% avg)

Mileage Analysis

30,190

Average miles

22,200

Expected for age

The average 2021 Mercedes G-Class had 30,190 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 2019 model has the highest MOT pass rate at 96%, while the 2017 model has the lowest at 86%. The 2021 scores 78%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

Mercedes G-Class by Year

Year	Pass Rate	Tests	Avg Mileage
2021	78%	65	30,190 mi
2020	98%	66	32,570 mi
2019	96%	319	41,698 mi
2018	94%	807	39,199 mi
2017	86%	691	43,730 mi
2016	94%	604	58,012 mi
2015	88%	591	48,991 mi
2014	92%	362	54,969 mi
2013	94%	449	69,675 mi
2012	90%	221	76,209 mi
2011	96%	92	70,666 mi
2010	73%	33	78,145 mi
2007	100%	35	103,461 mi
2001	60%	42	93,234 mi
1999	82%	44	113,541 mi

Similar Cars to Consider

Ford Focus

2019 · 1499cc Diesel

£1,824/year

89%

+11%

Mercedes A

2019 · 1461cc Diesel

£1,674/year

91%

+13%

Ford Kuga

2019 · 1997cc Diesel

£1,852/year

91%

+13%

Volkswagen Polo

2019 · 1598cc Diesel

£1,824/year

89%

+11%

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About the 2021 Mercedes G-Class

The 2021 Mercedes G-Class is a premium car. Our records list a 1950cc diesel engine, though engines vary between versions. 65 MOT tests were recorded on this model in 2024, making it a rare model on UK roads. It sits in the bottom 2% of 2021 models for MOT pass rate.

With an average of 30,190 miles recorded at its 2024 MOT tests, Mercedes G-Class owners cover more miles than the average driver.

2021 Mercedes G-Class Fuel Costs

The 1950cc diesel engine offers a reasonable balance between performance and economy. Expect around 48 mpg in mixed driving, which works out to roughly £1,397 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 2021 Mercedes G-Class?

Total estimated annual running cost is £2,152 (£179/month), broken down as £1,397 fuel, £200 road tax, £55 MOT, and £500 predicted repairs. Repair costs are moderate, reflecting the 78% pass rate. Keeping on top of servicing will help avoid surprises.

Mercedes G-Class Reliability Trend

The Mercedes G-Class has maintained consistent MOT pass rates across model years, varying by only 2 percentage points.

Buying a Used 2021 Mercedes G-Class

At 5 years old, the Mercedes G-Class 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 96%. Note: with only 65 tests in our data, these figures should be treated as indicative rather than definitive.

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

Low risk

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

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 2021 Mercedes G-Class 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 G-Class(2021)	78%	£1,397	£200	Grp 18-32	£2,152
Ford Focus(2019)	89%	£1,219	£200	Grp 12-25	£1,824-£328
Mercedes A(2019)	91%	£1,219	£200	Grp 12-25	£1,674-£478
Ford Kuga(2019)	91%	£1,397	£200	Grp 18-32	£1,852-£300
Volkswagen Polo(2019)	89%	£1,219	£200	Grp 12-25	£1,824-£328

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 G-Class

Is the 2021 Mercedes G-Class reliable?

Average reliability. Expect some repairs as it ages. 78% of MOT tests on 2021 Mercedes G-Classs ended in a pass, from 65 tests (DVSA MOT data for tests in 2024, retests included). That's 4 points below the average of 82% across all models in the same data.

How much does a 2021 Mercedes G-Class cost to run?

Our estimate is £2,152 a year (£179 a month): £1,397 fuel, £200 road tax, £55 MOT and £500 predicted repairs, based on 7,400 miles a year. Insurance is not included.

What is the MOT pass rate for a 2021 Mercedes G-Class?

78% of 65 MOT tests on the 2021 Mercedes G-Class ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 3300th of 3,336 models first registered in 2021 (bottom 2%).

Which year Mercedes G-Class has the best MOT pass rate?

Of the years with at least 100 tests, the 2019 Mercedes G-Class has the highest MOT pass rate at 96% and the 2017 the lowest at 86%. 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 G-Class?

The average mileage recorded at MOT tests on the 2021 Mercedes G-Class is 30,190 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.