Mercedes Benz
3,414 MOT tests analysed. sits above the UK fleet average — here's where Glc 300 Amg Line 4matic Autos pass, fail, and end up on the retest sheet.
That's 13.7 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
91.2%
Pass-after-fix
2.4%
Fail
6.0%
Avg miles
31,158
Pass + Pass-after-fix + Fail = 100%
Petrol cars first registered from January 2006 meet Euro 4 — compliant in London ULEZ, Birmingham CAZ, Bristol CAZ, and Glasgow LEZ.
Performance by cohort
2 year bands · 3,414 tests
Pass rate climbs 1.3 points across the cohorts — newer Glc 300 Amg Line 4matic Auto examples clear the test more reliably than the early cars.
Pass
91.0%
Fail
6.1%
PRS
2.6%
Avg mileage at test
32,705 mi
Pass
92.2%
Fail
5.9%
PRS
1.5%
Avg mileage at test
25,968 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 1,535 MOT tests, the Glc 300 Amg Line 4matic Auto returns 93.3% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is tyre tread under the limit. A seriously damaged tyre and windscreen damage round out the top three. Average tested mileage sits at 24,239, 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
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Tyre tread depth not in accordance with the requirements
53 occurrences · 1.6% of tests
A tyre seriously damaged
41 occurrences · 1.2% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
37 occurrences · 1.1% of tests
A tyre cords visible or damaged
19 occurrences · 0.6% of tests
Wiper blade defective
19 occurrences · 0.6% of tests
Brake lining or pad worn down to wear indicator
14 occurrences · 0.4% of tests
a brake lining or pad worn below 1.5mm
12 occurrences · 0.4% of tests
Wiper blade missing or obviously not clearing the windscreen
8 occurrences · 0.2% of tests
Number plate does not conform to the specified requirements
7 occurrences · 0.2% of tests
A suspension pin, bush or joint excessively worn
7 occurrences · 0.2% 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
£140–£235
If every one of this Glc 300 Amg Line 4matic Auto'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. A 1.3-point gap between bands is modest — the year you buy Mercedes Benz Glc 300 Amg Line 4matic Auto makes a small but real difference to MOT outcomes.
Best band to buy
92.2%
2021+ registration
the 2021-on band climbs to 92.2% — a 1.3-point improvement. Tests in this band average 25,968 miles — roughly 7K miles fewer on the clock than the older band. Failures here are mostly wear items: has a cut in excess of the…, tread depth below requirements of 1.6mm — 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
91.0%
2018–2020 registration
On the 2018–2020 band, the data shows a 91.0% pass rate against a fleet average of 92.2% on the newer band. The main culprits logged at test: tread depth below requirements of 1.6mm, damaged but not adversely affecting driver's view, and has a cut in excess of the…. Average mileage on test for this band is 32,705 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 (91.0% pass). That's a 1.3-point spread across 2,630 older tests and 784 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
Digital tyre-tread depth gauge
Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.
Search Amazon UK
Item 02 · 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
My Motor World · affiliate
Affiliate links — small commission, no extra cost to you.
Click Mechanic · affiliate
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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 4matic Auto 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.
