Is the 2018 MERCEDES GL reliable?

Excellent reliability. Very few MOT failures. 95% of MERCEDES GLs from 2018 passed their MOT first time in 2026, based on 63 tests. That's 13 points above the national average of 82%.

How much does a 2018 MERCEDES GL cost to run?

Estimated annual running cost is £2,042 (£170/month), including £1592 fuel, £195 road tax, £55 MOT, and £200 predicted repairs.

What is the MOT pass rate for a 2018 MERCEDES GL?

The 2018 MERCEDES GL has a 95% MOT pass rate based on 63 tests in 2026. This ranks 122 out of 649 cars from 2018.

Which year MERCEDES GL is most reliable?

The 2020 MERCEDES GL has the highest MOT pass rate at 100%. The least reliable year is 2006 at 78%.

MERCEDES GL (2018)

Q: What is the average mileage for a 2018 MERCEDES GL?

The average mileage for a 2018 MERCEDES GL is 38,524 miles, which is below the expected 59,200 miles for a 8-year-old car. This suggests lighter use than average, which generally means less wear on major components.

Running costs, reliability data, and common problems from 63 real MOT tests.

Annual Cost

£2,042

£170/month

MOT Pass Rate

95%

Excellent

Road Tax

£195

Flat rate/year

Insurance

Grp 35-50

5461cc Petrol

Great Choice

95% pass rate, £2042/year to run. 13 points above average.

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Petrol5461cc8 years old63 tests39k miles avg

Annual Running Costs

Fuel (Petrol, 5461cc)

~30 mpg

£1,592

Road Tax

Flat rate (post-2017)

£195

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£2,042

Per month£170/mo

Per week£39/wk

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

95% MOT pass rate(Excellent)

0%National avg: 82%100%

Excellent reliability. Very few MOT failures. That's 13 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.

At 8 years old, 95% of MERCEDES GLs from 2018 passed their MOT first time in 2026. That's based on 63 tests across the UK. The average mileage at this age is 38,524 miles.

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How Does It Compare?

Rank among 2018 cars122th of 649(top 19%)

Rank among MERCEDES models265th of 1,408(top 19%)

vs national average+13%(82% avg)

vs 2018 cars average+6%(89% avg)

vs MERCEDES average+8%(87% avg)

Mileage Analysis

38,524

Average miles

59,200

Expected for age

The average 2018 MERCEDES GL has 38,524 miles on the clock, which is below the expected 59,200 miles for a 8-year-old car. This suggests lighter use than average, which generally means less wear on major components.

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Best Year to Buy?

The most reliable year is the 2020 model with a 100% MOT pass rate, while the 2006 model has the lowest at 78%. The 2018 sits between the two at 95%.

MERCEDES GL by Year

Year	Pass Rate	Tests	Avg Mileage
2021	99%	71	29,185 mi
2020	100%	69	41,984 mi
2019	93%	137	35,018 mi
2018	95%	63	38,524 mi
2017	79%	47	108,751 mi
2016	88%	475	73,156 mi
2015	89%	1,283	79,394 mi
2014	92%	1,321	93,766 mi
2013	90%	1,304	103,757 mi
2012	89%	225	99,410 mi
2011	86%	609	116,582 mi
2010	89%	435	121,550 mi
2009	81%	224	126,000 mi
2008	84%	371	122,229 mi
2007	85%	572	130,779 mi
2006	78%	160	123,042 mi

Similar Cars to Consider

LAND ROVER RANGE ROVER

2017 · 4999cc Petrol

£2,037/year

91%

-4%

MERCEDES S-CLASS

2017 · 5461cc Petrol

£2,037/year

93%

-2%

JAGUAR F-TYPE

2017 · 5000cc Petrol

£2,037/year

94%

-1%

MERCEDES SLK

2016 · 5461cc Petrol

£2,247/year

89%

-6%

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About the 2018 MERCEDES GL

The 2018 MERCEDES GL is a performance with a 5461cc petrol engine. 63 of these vehicles were MOT tested in 2026, making it a rare model on UK roads. It ranks in the top 19% of all 2018 cars for reliability.

With an average of 38,524 miles at 8 years old, MERCEDES GL owners tend to use this car less than the typical driver.

2018 MERCEDES GL Fuel Costs

The 5461cc 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 2018 MERCEDES GL?

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 95% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

MERCEDES GL Reliability Trend

Newer MERCEDES GLs show better MOT pass rates than older ones, with an average improvement of 9 percentage points.

Buying a Used 2018 MERCEDES GL

At 8 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2020 model has the highest pass rate at 100%. Note: with only 63 tests in our data, these figures should be treated as indicative rather than definitive.

Common Issues to Watch For

Based on the 2018 MERCEDES GL's fuel type, age, and engine size, these are the most likely problem areas to check.

Timing Chain / Belt

Watch out

At 8 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

Medium risk

Larger petrol engines can develop higher oil consumption as they age. Check the oil level and look for blue smoke from the exhaust.

Suspension Wear

Medium risk

Shock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.

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 2018 MERCEDES GL stacks up against similar cars for annual running costs, insurance, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Insurance	Total/yr
MERCEDES GL(2018)	95%	£1592	£195	Grp 35-50	£2042
LAND ROVER RANGE ROVER(2017)	91%	£1592	£190	Grp 35-50	£2037-£5
MERCEDES S-CLASS(2017)	93%	£1592	£190	Grp 35-50	£2037-£5
JAGUAR F-TYPE(2017)	94%	£1592	£190	Grp 35-50	£2037-£5
MERCEDES SLK(2016)	89%	£1592	£250	Grp 35-50	£2247+£205

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.