Mercedes Benz
4,751 MOT tests analysed. sits above the UK fleet average — here's where G Classs pass, fail, and end up on the retest sheet.
That's 11.2 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
88.7%
Pass-after-fix
2.0%
Fail
8.6%
Avg miles
55,193
Pass + Pass-after-fix + Fail = 100%
This model's production run straddles the January 2006 Euro 4 cutoff. Individual cars vary — check your registration plate on the government's ULEZ checker. Daily charges if driven in the zone: London £12.50 · Birmingham £8.00 .
Performance by cohort
2 year bands · 4,685 tests
Pass rate climbs 7.9 points across the cohorts — newer G Class examples clear the test more reliably than the early cars.
Pass
87.3%
Fail
9.5%
PRS
2.4%
Avg mileage at test
59,427 mi
Pass
95.1%
Fail
3.9%
PRS
0.7%
Avg mileage at test
40,307 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 1,573 MOT tests, the G-Class returns 84.9% first-time pass — above the UK fleet average. The single most-logged Major fail is a broken or weak spring. Windscreen damage and a seriously damaged tyre round out the top three. Average tested mileage sits at 49,755, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
ABI Insurance Group
A high-group car — insurance costs will be significantly above average. Lower groups cost less to insure; UK fleet average is around Group 22.
Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →
28–46
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Steering rack gaiter or ball joint dust cover damaged or deteriorated
73 occurrences · 1.5% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
58 occurrences · 1.2% of tests
A spring or spring component fractured or seriously weakened
50 occurrences · 1.1% of tests
Wiper blade defective
44 occurrences · 0.9% of tests
Number plate does not conform to the specified requirements
44 occurrences · 0.9% of tests
The aim of a headlamp is not within limits laid down in the requirements
42 occurrences · 0.9% of tests
A tyre seriously damaged
40 occurrences · 0.8% of tests
Windscreen or window excessively tinted but not adversely affecting driver's view
34 occurrences · 0.7% of tests
Steering rack gaiter or ball joint dust cover damaged or deteriorated
29 occurrences · 0.6% of tests
The aim of a headlamp is not within limits laid down in the requirements
24 occurrences · 0.5% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 4 failures
£195–£560
If every one of this G Class's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
Try the calculator
Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. A 7.9-point gap between bands means the year you buy Mercedes Benz G Class has a real effect on what turns up at the garage.
Best band to buy
95.1%
2018–2020 registration
the 2018–2020 band climbs to 95.1% — a 7.9-point improvement. Tests in this band average 40,307 miles — roughly 19K miles fewer on the clock than the older band. Failures here are mostly wear items: excessively tinted but not adversely affecting driver's view, has a bulge, caused by separation or… — the structural issues that drag down older examples don't appear in the top-10 for this band. The stricter post-2018 MOT test rules meant manufacturers had to tighten up emissions and electrical checks, but this band still shows far fewer major failures on suspension and bodywork than the older fleet.
Band to be cautious about
87.3%
Pre-2018 registration
On the older band (pre-2018), the data shows a 87.3% pass rate against a fleet average of 95.1% on the newer band. The main culprits logged at test: ball joint dust cover damaged or deteriorated, but preventing the ingress of dirt, damaged but not adversely affecting driver's view, and fractured or broken. Average mileage on test for this band is 59,427 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2018-2020 (95.1% first-time pass). Worst band to avoid: pre-2018 (87.3% pass). That's a 7.9-point spread across 3,740 older tests and 945 newer ones — year of build makes a material difference on this model.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Item 01 · Amazon UK
Bosch Aerotwin wiper blades
Cheap wipers fail the test on smear streaks. Bosch Aerotwins last a winter and clear a screen properly.
Search Amazon UK
Item 02 · Amazon UK
MOT-spec replacement number plate
Faded or non-standard plates fail outright. Replacements take ten minutes online with V5C details.
Search Amazon UK
My Motor World · affiliate
Affiliate links — small commission, no extra cost to you.
Click Mechanic · affiliate
Affiliate links — small commission, no extra cost to you.
Mobile mechanic · UK-wide
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Recall history
The G Class has 27 official UK vehicle recalls covering defect details, remedies, and affected build dates.
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a G Class and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.
