Is the 2018 MERCEDES GLC reliable?

Excellent reliability. Very few MOT failures. 91% of MERCEDES GLCs from 2018 passed their MOT first time in 2026, based on 40,494 tests. That's 9 points above the national average of 82%.

How much does a 2018 MERCEDES GLC cost to run?

Estimated annual running cost is £1,695 (£141/month), including £1245 fuel, £195 road tax, £55 MOT, and £200 predicted repairs.

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

The 2018 MERCEDES GLC has a 91% MOT pass rate based on 40,494 tests in 2026. This ranks 262 out of 649 cars from 2018.

Which year MERCEDES GLC is most reliable?

The 2022 MERCEDES GLC has the highest MOT pass rate at 96%. The least reliable year is 2015 at 89%.

What is the average mileage for a 2018 MERCEDES GLC?

The average mileage for a 2018 MERCEDES GLC is 51,301 miles, which is in line with the expected 59,200 miles for a 8-year-old car, suggesting normal everyday use.

MERCEDES GLC (2018)

Running costs, reliability data, and common problems from 40,494 real MOT tests.

Annual Cost

£1,695

£141/month

MOT Pass Rate

91%

Excellent

Road Tax

£195

Flat rate/year

Insurance

Grp 30-42

2987cc Diesel

Great Choice

91% pass rate, £1695/year to run. 9 points above average.

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Diesel2987cc8 years old40,494 tests51k miles avg

Annual Running Costs

Fuel (Diesel, 2987cc)

~40 mpg

£1,245

Road Tax

Flat rate (post-2017)

£195

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£1,695

Per month£141/mo

Per week£33/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

91% MOT pass rate(Excellent)

0%National avg: 82%100%

Excellent reliability. Very few MOT failures. That's 9 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.

At 8 years old, 91% of MERCEDES GLCs from 2018 passed their MOT first time in 2026. That's based on 40,494 tests across the UK. The average mileage at this age is 51,301 miles.

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How Does It Compare?

Rank among 2018 cars262th of 649(top 40%)

Rank among MERCEDES models540th of 1,408(top 38%)

vs national average+9%(82% avg)

vs 2018 cars average+2%(89% avg)

vs MERCEDES average+4%(87% avg)

Mileage Analysis

51,301

Average miles

59,200

Expected for age

The average 2018 MERCEDES GLC has 51,301 miles on the clock, which is in line with the expected 59,200 miles for a 8-year-old car, suggesting normal everyday use.

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Best Year to Buy?

The most reliable year is the 2022 model with a 96% MOT pass rate, while the 2015 model has the lowest at 89%. The 2018 sits between the two at 91%.

MERCEDES GLC by Year

Year	Pass Rate	Tests	Avg Mileage
2022	96%	294	25,971 mi
2021	95%	6,414	29,460 mi
2020	94%	9,614	36,815 mi
2019	93%	30,341	42,501 mi
2018	91%	40,494	51,301 mi
2017	90%	28,866	61,718 mi
2016	89%	19,967	71,320 mi
2015	89%	3,031	76,191 mi

Similar Cars to Consider

MERCEDES E

2019 · 2925cc Diesel

£1,690/year

90%

-1%

AUDI A5

2017 · 2967cc Diesel

£1,840/year

89%

-2%

FORD RANGER

2019 · 3198cc Diesel

£1,840/year

87%

-4%

LAND ROVER RANGE ROVER VELAR

2018 · 2993cc Diesel

£1,690/year

91%

same

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About the 2018 MERCEDES GLC

The 2018 MERCEDES GLC is a large car with a 2987cc diesel engine. 40,494 of these vehicles were MOT tested in 2026, making it one of the most commonly tested cars on UK roads. Among all cars from 2018, the average MOT pass rate is 89%, and this model beats that benchmark.

With an average of 51,301 miles at 8 years old, MERCEDES GLC owners drive about as much as the UK average.

2018 MERCEDES GLC Fuel Costs

The 2987cc 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 2018 MERCEDES GLC?

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 91% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

MERCEDES GLC Reliability Trend

Newer MERCEDES GLCs show better MOT pass rates than older ones, with an average improvement of 5 percentage points.

Buying a Used 2018 MERCEDES GLC

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 2022 model has the highest pass rate at 96%. With 40,494 MOT tests in our data, there's strong statistical confidence in these figures.

Common Issues to Watch For

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

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

Watch out

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

Watch out

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

Dual Mass Flywheel

Watch out

Larger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.

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 GLC stacks up against similar cars for annual running costs, insurance, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Insurance	Total/yr
MERCEDES GLC(2018)	91%	£1245	£195	Grp 30-42	£1695
MERCEDES E(2019)	90%	£1245	£190	Grp 30-42	£1690-£5
AUDI A5(2017)	89%	£1245	£190	Grp 30-42	£1840+£145
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.