Mercedes Benz
7,743 MOT tests analysed. sits above the UK fleet average — here's where Glc 300 Amg Line Prem D 4M As pass, fail, and end up on the retest sheet.
That's 14.4 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
91.9%
Pass-after-fix
1.0%
Fail
6.7%
Avg miles
38,436
Pass + Pass-after-fix + Fail = 100%
Diesel cars registered from September 2015 generally meet Euro 6 — compliant in London ULEZ, Birmingham CAZ, Bristol CAZ, and Glasgow LEZ.
Performance by cohort
2 year bands · 7,743 tests
Pass rate is broadly flat across the cohorts — new and old Glc 300 Amg Line Prem D 4M A examples track each other at the test bay.
Pass
91.9%
Fail
6.8%
PRS
1.0%
Avg mileage at test
39,564 mi
Pass
92.2%
Fail
6.2%
PRS
1.1%
Avg mileage at test
33,610 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 3,044 MOT tests, the Glc 300 Amg Line Prem + D 4m A returns 91.5% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is a seriously damaged tyre. Windscreen damage and a tyre with the cords showing round out the top three. Average tested mileage sits at 30,093, 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 →
32–44
out of 50
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Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
147 occurrences · 1.9% of tests
A tyre seriously damaged
109 occurrences · 1.4% of tests
Tyre tread depth not in accordance with the requirements
86 occurrences · 1.1% of tests
A suspension pin, bush or joint excessively worn
71 occurrences · 0.9% of tests
A tyre cords visible or damaged
69 occurrences · 0.9% of tests
Wiper blade defective
46 occurrences · 0.6% of tests
a brake lining or pad worn below 1.5mm
36 occurrences · 0.5% of tests
Number plate does not conform to the specified requirements
29 occurrences · 0.4% of tests
Brake lining or pad worn down to wear indicator
22 occurrences · 0.3% of tests
Wiper blade missing or obviously not clearing the windscreen
20 occurrences · 0.3% 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 3 failures
£200–£430
If every one of this Glc 300 Amg Line Prem D 4M A'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 →
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Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. Pass rates barely move across bands here, so the year you buy Mercedes Benz Glc 300 Amg Line Prem D 4M A makes little measurable difference to MOT outcomes.
Best band to buy
92.2%
2021+ registration
the 2021-on band climbs to 92.2% — a 0.3-point improvement. Tests in this band average 33,610 miles — roughly 6K miles fewer on the clock than the older band. Failures here are mostly wear items: tread depth below requirements of 1.6mm, damaged but not adversely affecting driver's view — the structural issues that drag down older examples don't appear in the top-10 for this band. Post-2020 examples are early in their MOT life and generally show the cleanest records.
Band to be cautious about
91.9%
2018–2020 registration
On the 2018–2020 band, the data shows a 91.9% pass rate against a fleet average of 92.2% on the newer band. The main culprits logged at test: damaged but not adversely affecting driver's view, has a cut in excess of the…, and ball joint excessively worn. Average mileage on test for this band is 39,564 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2021+ (92.2% first-time pass). Worst band to avoid: 2018-2020 (91.9% pass). That's a 0.3-point spread across 6,283 older tests and 1,460 newer ones — year of build makes a material difference on this model.
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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 Glc 300 Amg Line Prem D 4M A 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.
