Mercedes-Benz C-Class 2018: MOT failure rate for its age

13.0% of 117,729 MOT tests of the Mercedes-Benz C-Class first registered in 2018 failed at the first attempt (2019–2024; retests excluded). Against this model's own normal rate at the same ages the index is 96.4 (95% CI 94.9–97.9; 100 = normal for this model at that age): close to other build years of the same model at the same age (within 5 points of normal).

Mercedes-Benz C-Class built in 2018 at a glance
Measure	Value	Unit	Compared with	Years	Tests
Failed first time	13.0	%	all ages tested	2019–2024	117729
Index against this model at the same age (95% CI 94.9–97.9)	96.4	index	100 = normal for this model at that age	2019–2024	117729
Rank among this model's 23 build years	7	of 23	1 = fails least for its age	2019–2024	117729
Tested in 2024	28654	tests	median 47,643 miles	2024	28654

Built 2018 against Mercedes-Benz C-Class normal for the age: first-time MOT failure share at each age, age 3: 11.5% vs 11.4%; age 4: 11.7% vs 12.5%; age 5: 13.8% vs 14.2%; age 6: 15.1% vs 16%. Axis from 0% to 20%. DVSA MOT bulk data, 2019–2024.

Check a 2018 Mercedes-Benz C-Class by registration · All Mercedes-Benz C-Class MOT statistics · Download the build-year table (CSV)

Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · full dataset (v5).

How does the 2018 Mercedes-Benz C-Class fail at each age?

Cars built in 2018 were tested at ages 3 to 6 between 2019 and 2024. Each row compares their first-time failure share with what this model normally shows at that age, after allowing for the overall failure level of each test year.

Mercedes-Benz C-Class built 2018: first-time MOT failure by age, against the model's normal rate at that age (2019–2024)
Age	Tests	Failed, %	95% interval	Normal for this model at that age, %	Index (100 = normal)
3	30,324	11.5	11.1–11.8	11.4	100.8
4	29,715	11.7	11.4–12.1	12.5	93.8
5	29,036	13.8	13.4–14.2	14.2	97.1
6	28,654	15.1	14.7–15.6	16	94.5

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 117,729 (initial tests) · Method: normal rate = this model's first-time failure share at that age across its build years (cells of 400+ tests), adjusted for each test year's overall level; cells of 30+ tests, under 500 marked rough · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

What fails most on the 2018 Mercedes-Benz C-Class?

The most common failure group on cars built in 2018 is tyres: 9.9 items per 100 first tests, against 10.5 across all build years of the Mercedes-Benz C-Class. These counts are not age-adjusted: cars built in 2018 were tested at ages 3 to 6.

Failure items per 100 first tests, Mercedes-Benz C-Class built 2018 against the Mercedes-Benz C-Class in all build years (2019–2024, not age-adjusted)
Failure group	Built 2018, per 100	All build years, per 100	Items
Tyres	9.9	10.5	11,851
Visibility	3.9	6.2	4,601
Brakes	1.7	10.6	1,999
Suspension	1.6	16.4	1,850
Lamps, reflectors and electrical equipment	1.1	9.2	1,346

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 119,126 (initial tests of this build year) · Method: failure items grouped by DVSA's top-level defect groups, per 100 initial tests; groups with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

How does 2018 compare with the years around it?

Among the 23 published build years of the Mercedes-Benz C-Class, 2018 ranks 7 (1 = fails least for its age). 2017: index 95.4. 2019: index 94.9.

Mercedes-Benz C-Class build years: index against the model at the same age (2019–2024)
Build year	Index (100 = normal)	95% interval	Verdict	Tests
1998	83.9	77.7–90.1	better (rough estimate)	2,061
1999	89.6	84.6–94.5	better (rough estimate)	3,506
2000	93.6	88.9–98.2	better	4,182
2001	100.3	97.0–103.6	no different	8,626
2002	99.8	97.7–102.0	no different	19,524
2003	105.1	103.5–106.7	worse	35,652
2004	107.1	105.7–108.5	worse	47,394
2005	105.4	104.1–106.7	worse	58,804
2006	102.8	101.6–104.1	worse	63,597
2007	101.3	100.2–102.5	worse	76,358
2008	98.7	97.6–99.8	better	85,264
2009	100.7	99.6–101.9	no different	83,898
2010	100.7	99.6–101.9	no different	93,206
2011	99.9	98.9–100.9	no different	132,283
2012	106.2	105.3–107.2	worse	167,665
2013	105.2	104.1–106.4	worse	139,585
2014	95.6	94.5–96.7	better	148,901
2015	98.8	97.8–99.8	better	214,864
2016	100.3	99.3–101.3	no different	230,659
2017	95.4	94.3–96.5	better	217,306
2018	96.4	94.9–97.9	better	117,729
2019	94.9	92.9–96.9	better	74,577
2020	103.2	98.5–107.9	no different	15,237

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 2,040,878 (initial tests) · Method: observed failures against those expected for the same model at the same ages, test-year level adjusted; verdict follows the printed one-decimal bound · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

How to cite this page

MOT Risk Index (2026). Mercedes-Benz C-Class 2018 MOT statistics (data release dvsa-2024-v2; full dataset motriskindex-families-2024-v5, DOI 10.5281/zenodo.22975051), updated 30 September 2026. motriskindex.co.uk/cars/mercedes-c-class/2018/

How every figure is calculated: methodology. Age, test year and build year are tied together (age = test year − build year), so the test-year level is taken as observed, not estimated.

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