MOT Risk Index.co.uk

Mercedes C Class — MOT statistics 2024

The Mercedes C Class failed 22.55% of 646,907 first MOT attempts in 2024 ("first-time", excluding retests). Adjusted for the age of the fleet, its initial-failure ratio is 83.6 (100 = expected for its age profile). This car fails its MOT about 16% less often than expected for its age.

MOT risk index 83.6, 95% CI 83.2–84.0 (100 = national average) 100 83.6 60 160
Index
83.6
100 = age-normal
Raw fail rate
22.55%
n = 646,907
Dangerous /100
16
national ≈13
Diesel − petrol
+1.5 pp
fail-rate gap
Rank
11 of 56
lower index = better

Age-adjusted peer: Land Rover Defender (index 84.4) — the two published results are 0.8 index points apart.

Mercedes C Class common problems: what actually fails the MOT

Lamps, reflectors and electrical equipment stand out at 12.7 per 100 tests, against 23.5 per 100 tests nationally.

higher bar = fails more oftenrate per 100 tests

Mercedes C Class common problems: what actually fails the MOT — 2024 UK MOT data

family vs national — top component groups, per 100 tests. Legend: This family · National avg.

Component-group comparison table
GroupThis familyNationalFamily / national
Suspension27.519.91.38×
Brakes14.114.30.98×
Tyres13.410.31.30×
Lamps & electrical12.723.50.54×
Visibility11.212.00.93×
Emissions & leaks4.44.90.90×
Named defects — items per 100 initial tests, this family vs UK national average, 2024
What failedper 100 tests (this family)per 100 tests (UK average)ratio family / UKWhat to check
Suspension joint dust cover severely deterioratedA suspension joint dust cover severely deteriorated7.953.452.30×Listen for knocks over bumps — worn suspension joints are common
Suspension pin, bush or joint excessively wornA suspension pin, bush or joint excessively worn9.026.031.50×Listen for knocks over bumps — worn suspension joints are common
Tyre tread depth not in accordance with the…Tyre tread depth not in accordance with the requirements5.723.821.50×Check tyre tread depth across the full width
Suspension joint dust cover missing or no longer…A suspension joint dust cover missing or no longer prevents the ingress of dirt etc3.902.251.73×Listen for knocks over bumps — worn suspension joints are common
Brake pipe damaged or excessively corrodedBrake pipe damaged or excessively corroded2.801.342.09×Feel for brake judder and pulling on the test drive
Windscreen or window damaged or seriously…Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view5.394.271.26×Check wipers, washers and windscreen chips in the driver's view
Spring or spring component fractured or seriously…A spring or spring component fractured or seriously weakened3.822.721.41×Ask the seller about: A spring or spring component fractured or seriously weakened
Engine MIL illuminated indicating a malfunctionEngine MIL illuminated indicating a malfunction2.391.461.64×Ask the seller about: Engine MIL illuminated indicating a malfunction
Tyre cords visible or damagedA tyre cords visible or damaged2.792.001.40×Check tyre tread depth across the full width
Tyre seriously damagedA tyre seriously damaged3.773.291.14×Check tyre tread depth across the full width

Named defects ranked by how much more often they appear than the national average — not by raw rate.

Mercedes C Class MOT advisories: what gets flagged

Tyres are highest at 93.5 per 100 tests; Body & structure are lowest at 5.1 per 100 tests — the gap is 88.4 per 100 tests.

higher bar = flagged more oftenadvisory items per 100 initial tests

Mercedes C Class MOT advisories: what gets flagged — 2024 UK MOT data
Advisory rates table
GroupAdvisories per 100
Tyres93.5
Brakes80.3
Suspension49.7
Non-component advisories9.4
Emissions & leaks8
Body & structure5.1

Advisories are wear the tester noted but didn't fail — what will need money soon.

How does the Mercedes C Class perform as it gets older?

At age 10 stands out at 20.5%, against 27.7% for all cars of the same age.

higher = larger sharecompare shares in percentage points

How does the Mercedes C Class perform as it gets older? — 2024 UK MOT data

Chart axes: car age, years · failure-rate scale 0–46%.

Takeaway: a 10-year-old C Class has roughly a 21% chance of failing its MOT.

Data table
AgeMercedes C ClassAll carsGap
310.0%10.9%-0.9 pp
49.8%11.6%-1.8 pp
510.8%13.5%-2.6 pp
612.5%15.6%-3.1 pp
714.6%18.2%-3.6 pp
816.0%21.3%-5.2 pp
918.7%24.4%-5.7 pp
1020.5%27.7%-7.2 pp
1126.9%30.6%-3.7 pp
1228.7%33.4%-4.6 pp
1329.2%36.0%-6.9 pp
1431.6%38.6%-7.0 pp
1533.3%39.9%-6.6 pp
1634.5%41.5%-7.0 pp
1737.2%41.5%-4.4 pp
1840.5%42.4%-1.9 pp
1941.3%42.2%-0.9 pp
2036.9%37.5%-0.5 pp

Is a Mercedes C Class ULEZ compliant?

The share of classifiable 2024 Mercedes C Class MOT tests likely ULEZ compliant by first-registration date is 58.9%.

Based on 646,809 classifiable initial MOT tests. This describes the tested fleet, not a specific car. MOT data do not record Euro class, so likely compliance is inferred from fuel and first-registration date. For the only authoritative answer, check the registration with TfL's official ULEZ checker.

higher = larger share likely compliantinferred from fuel and first-registration date; not a recorded Euro class

Age-band estimate from classifiable initial MOT tests
Vehicle age at testLikely ULEZ-compliant shareTests
Under 3 yearsSuppressed — sample below publication threshold
Check a registration with TfL
n = 10
3–5 years100.0%
Check a registration with TfL
n = 65,857
6–7 years100.0%
Check a registration with TfL
n = 131,509
8 years100.0%
Check a registration with TfL
n = 69,286
9 years46.6%
Check a registration with TfL
n = 60,913
10–14 years26.1%
Check a registration with TfL
n = 190,431
15–17 years41.8%
Check a registration with TfL
n = 65,813
18 years58.6%
Check a registration with TfL
n = 15,455
19 years0.0%
Check a registration with TfL
n = 13,818
20+ years0.0%
Check a registration with TfL
n = 33,717

Mercedes C Class petrol vs diesel: which ages best

Diesel is highest at 23.5%; Hybrid is lowest at 12.8% — the gap is 10.8 percentage points.

higher = larger sharecompare shares in percentage points

Mercedes C Class petrol vs diesel: which ages best — 2024 UK MOT data
Fuel split table
FuelTests% failingGap vs best
Diesel393,07023.5%+10.8 pp
Petrol224,25122.0%+9.3 pp
Hybrid23,30912.8%+0.0 pp
Electric-diesel6,16216.0%+3.3 pp

Chart sample sizes: n=393k · n=224k · n=23k · n=6,162.

How dangerous are Mercedes C Class MOT failures?

Major defects stand out at 51.9 per 100 tests, against 63.3 per 100 tests nationally.

higher bar = fails more oftenrate per 100 tests

How dangerous are Mercedes C Class MOT failures? — 2024 UK MOT data
Severity table
SeverityThis family /100National /100Family / national
Minor22.5024.380.92×
Major51.8563.260.82×
Dangerous15.6812.891.22×

Chart values: Minor 22.5 · Major 51.9 · Dangerous 15.7.

Per 100 tests on this family. National average: Minor 24.4 · Major 63.3 · Dangerous 12.9 per 100.

Does the month of a Mercedes C Class MOT matter?

Oct is highest at 23.9%; Mar is lowest at 21.1% — the gap is 2.8 percentage points.

higher = larger sharecompare shares in percentage points

Does the month of a Mercedes C Class MOT matter? — 2024 UK MOT data

Chart scale: 20%–29%.

bars: Mercedes C Class · dashed: all class-4 cars

Month-by-month table
MonthMercedes C ClassAll carsGap
Jan22.59%27.37%-4.8 pp
Feb22.07%26.14%-4.1 pp
Mar21.11%24.75%-3.6 pp
Apr22.78%26.01%-3.2 pp
May21.16%25.01%-3.9 pp
Jun22.15%25.01%-2.9 pp
Jul23.09%26.04%-2.9 pp
Aug22.55%25.79%-3.2 pp
Sep22.47%25.19%-2.7 pp
Oct23.86%27.13%-3.3 pp
Nov23.76%27.2%-3.4 pp
Dec23.28%26.29%-3.0 pp

Takeaway: the spread between best and worst month is 2.8 percentage points — booking month barely matters for this family. Seasonality partly reflects registration-date clustering, not weather.

Before reading the shape: most of it is not about cars. Britain changes its registration plates twice a year, and 19.5% of these cars were first registered in March with another17% in September — 37% in two months against the 17% an even spread would give. An MOT falls due three years after first registration, so the buying calendar becomes the testing calendar. Peaks here mark when cars are tested, not when they are worse.

Mercedes C Class average mileage by age

At age 8, the middle half of C Classs runs from 51,270 miles to 88,872 miles, against 68,301 miles as the median.

further right = more milesmedian is the typical car; band is p25–p75

Bars: Mercedes C Class · dashed: all class-4 cars — 2024 UK MOT data

Chart axes: car age, years · odometer scale 0–156k mi.

Does high mileage mean more Mercedes C Class MOT failures?

Same age band (6–14 years), split by odometer — this separates wear from age: 10.2% of the lowest-mileage cars failed versus 31.4% of the highest.

Does high mileage mean more Mercedes C Class MOT failures? — 2024 UK MOT data
Odometer% failingTestsGap vs lowest-mileage band
<40k miles10.2%56,369+0.0 pp
40-70k miles15.7%144,486+5.5 pp
70-100k miles21.8%128,436+11.6 pp
100-140k miles27.4%87,936+17.2 pp
140k+ miles31.4%34,603+21.2 pp

line: median · band: middle half of the fleet (p25–p75)

Mileage by age (p25 / median / p75)
Agep25Medianp75Tests
317,28824,57933,1083,446
421,53530,73542,73514,765
527,40337,73349,84447,662
634,73147,14062,47055,173
741,83756,74673,96676,338
851,27068,30188,87269,290
960,31179,717103,23460,915
1065,10685,445109,09045,816
1169,98591,474117,97841,462
1274,92097,936123,72146,853
1382,139105,953131,83433,769
1482,162107,100133,89822,551
1589,946115,902143,63822,240
1690,690118,147147,86523,698
1787,588115,086144,60319,896
1887,726113,737143,07915,461
1989,994118,152148,74113,822
20+80,771107,864137,84033,740

A typical 8-year-old C Class has ~68,301 miles on the clock. Much more — ask why; much less — check for gaps in the MOT history.

Where in Britain the Mercedes C Class fails its MOT most

Aberdeen area is highest at 34.5%; London E area is lowest at 15.9% — the gap is 18.6 percentage points.

higher = larger sharecompare shares in percentage points

Where in Britain the Mercedes C Class fails its MOT most — 2024 UK MOT data
Toughest areas% failingvs model overall
Aberdeen (AB)34.47%+11.9 pp
Dundee (DD)32.29%+9.7 pp
Exeter (EX)31.96%+9.4 pp
Salisbury (SP)31.2%+8.6 pp
Bath (BA)30.82%+8.3 pp
Easiest areas% failingvs model overall
London E (E)15.91%-6.6 pp
Uxbridge (UB)16.06%-6.5 pp
Blackburn (BB)16.49%-6.1 pp
Enfield (EN)16.77%-5.8 pp
Bradford (BD)17.34%-5.2 pp

Why do areas differ?

For each external factor we correlate the area fail rate with the factor across postcode areas that have ≥800 tests of this family, then compare the bottom vs top fifth (quintile) of the factor. Correlation, not causation — factors travel together (the north is colder and often poorer; urban areas are denser and less salted). Road surface condition is joined now, for the 91 English areas the DfT publishes, and it explains nothing: the correlation with suspension failures is −0.01 and with body and structure failures 0.07. Potholes wreck wheels and tyres between tests, but by the time a car reaches the bay the road it drives on leaves no measurable trace.

In areas with the highest urban share this model fails 7.1 pp less often than in the lowest fifth (r=-0.55, n=113 areas with ≥800 tests).

In areas with the highest mot centre density this model fails 6.2 pp more often than in the lowest fifth (r=0.51, n=113 areas with ≥800 tests).

In the most coastal fifth of areas this model fails 4.4 pp more often than in the most inland fifth (r=-0.42, n=113 areas with ≥800 tests).

Mercedes C Class Why do areas differ? — 2024 UK MOT data
Values shown in the quintile chart
FactorLow QHigh QGapCorrelation
Urban share26.3%19.2%-7.1 ppr=-0.55
MOT centre density19.8%26.0%+6.2 ppr=0.51
Distance to coast26.1%21.7%-4.4 ppr=-0.42

Factors that only mean something combined

Some conditions are useless on their own and informative multiplied together. Frost days alone say little — Britain barely freezes. Salt tonnage alone says little — it tracks frost. Distance to the sea alone says little. Multiply the first two and divide by the third and you get an index of how hard an area attacks a car's underside, and it lines up with the corrosion defects we actually record. We built five such combinations and tested each against our own data. Three survived; two did not, and the failures are listed here on purpose — a proxy that was never checked is decoration. One survivor only survived on the second attempt: built from a crude stand-in for street parking it failed outright, and rebuilt from the census — terraced streets carrying more cars than they have driveways — it works, and carries information the salt index does not.

Composite area indicators, each tested against a defect rate we measure
CompositeBuilt fromTested againstrVerdict
Underbody corrosionfrost days × salt load ÷ (distance to coast + 1)share of tests with a corrosion defect+0.42holds (116 areas)
Tyre wearrain days × annual miles ÷ age at first tyre advisoryshare of tests failing on tyres+0.45holds (116 areas)
Overnight corrosionterraced housing × cars per household × frost daysshare with a corrosion defect+0.41holds (102 areas) — and adds signal beyond the first index
Deferred maintenancedeprivation × advisory-to-failure conversion ÷ labour ratecars repeating the same advisory−0.26fails (118 areas)
Powertrain stressengine capacity ÷ kerb weightsuspension, brake and emissions failures−0.16fails (22 models)

The deprivation result is the one worth dwelling on. The intuition that poorer areas defer repairs is strong enough that most people treat it as established. We tested it twice — once on raw failure rates (r = 0.04) and again, more fairly, on whether an advisory turns into a failure — and it did not hold any of the three times we tried it — on raw failure rates, on advisory-to-failure conversion, and again with deprivation measured properly inside each nation rather than England alone. We are closing it. What does predict local failure rates is the density of test centres, which is a statement about testing, not about cars.

All external-factor correlations (machine-readable)
Factorrn areasLow-Q fail %High-Q fail %Gap ppLow-Q factorHigh-Q factor
Urban share (0–1)-0.54611326.319.2-7.10.41
MOT centre density (per 10k vehicles)0.51111319.826.0+6.258.5
Distance to coast (km)-0.41611326.121.7-4.46.279.5
Income deprivation (score)-0.2299723.621.0-2.60.10.2
Frost days (days/year)0.18511323.524.5+1.011.638
Road-salt proxy (g/m²-yr)0.16811322.224.5+2.3221.2670.1
Terrain gradient (% grade)0.1616723.526.0+2.40.53.7

Deprivation uses England IMD 2019 income score only (Scotland SIMD is a different scale). Salt proxy is a simplified NWSRG-style dry-salt sum from air Tmin; coastalness is distance from the area centroid to the nearest coastline.

Every dot is a postcode area — size = how many were tested there, colour = share failing. These figures are not age-adjusted: coastal and rural areas often run older fleets and salted roads, so higher raw fail rates do not automatically mean a worse local stock of this model.

Map labels: Scotland · N. England · Wales · London · S. West. Colour scale: 18%–31% failing.

Mercedes C Class survival: which cars are still on the road

By age 19 stands out at 35.3%, against 100% at the ages 4–6 reference level.

higher = larger sharecompare shares in percentage points

Mercedes C Class survival: which cars are still on the road — 2024 UK MOT data

Chart axes: car age, years · survival vs ages 4–6 · scale 0–105%.

Survival vs fail rate by age
AgeTestsSurvival vs ages 4–6Fail %
33,4468.8%9.98%
414,76537.7%9.79%
547,662100%10.84%
655,173100%12.5%
776,338100%14.61%
869,290100%16.04%
960,915100%18.68%
1045,816100%20.52%
1141,462100%26.91%
1246,853100%28.75%
1333,76986.1%29.18%
1422,55157.5%31.63%
1522,24056.7%33.29%
1623,69860.5%34.49%
1719,89650.8%37.19%
1815,46139.4%40.53%
1913,82235.3%41.28%

DfT licensed stock: peak 415,102 (2018 Q4) → latest 325,224 (78.3% of peak).

By age 19, only about 35% as many cars of this family present for MOT as at ages 4–6 (reference n≈39,200); survivors still fail at 41.3% vs 9.8% at age 4. Older cars that still appear are a selected subset — weaker ones have already left. DfT licensed stock is 78% of its 2018 Q4 peak (415,102 → 325,224).

How many miles does a Mercedes C Class last?

100,000+ miles is highest at 31.7%; 200,000+ miles is lowest at 1.3% — the gap is 30.4 percentage points.

higher = larger sharecompare shares in percentage points

OdometerTests ≥ thresholdShare of sample
100,000+ miles204,50131.66%
150,000+ miles50,4317.81%
200,000+ miles8,3401.29%

Of 645,999 tests of this family with a usable odometer in 2024, 31.7% had already reached 100k miles, 7.8% reached 150k, and 1.3% reached 200k — a cross-section of cars still presenting for MOT, not a full birth cohort.

How many years is a Mercedes C Class likely to last?

Bought at age 5 is highest at 11.4 years; Bought at age 15 is lowest at 3.8 years — the gap is 7.6 years.

bigger number = longer remaining lifeyears on the observed survival curve

Age nowTypical mileage (p50)Expected years left
537,73311.4
868,3018.4
1085,4456.4
1297,9364.4
15115,9023.8

estimateEstimate only — not a warranty: a typical 10-year-old example of this family (~85,445 miles median) has about 6.4 expected years of further MOT-present life on the 2024 survival curve. Derived from how many cars of each age still appear for test, not from a longitudinal panel.

Mercedes C Class faults that come together

Body & structure + Emissions & leaks stand out at 13.03×, against if the faults were independent.

above 1.0× = more than expectedbelow 1.0× = less

Group AGroup BTogetherLift
Body, chassis, structureNoise, emissions and leaks94613.03×
Noise, emissions and leaksSeat belts and supplementary restraint systems61011.09×
Lamps, reflectors and electrical equipmentSeat belts and supplementary restraint systems1,25711.08×
Body, chassis, structureLamps, reflectors and electrical equipment1,4539.7×
Lamps, reflectors and electrical equipmentSteering1,0569.26×
BrakesSeat belts and supplementary restraint systems1,0849.14×
Body, chassis, structureBrakes1,4279.11×
Noise, emissions and leaksSteering4598.3×

Defects in «Body, chassis, structure» and «Noise, emissions and leaks» appear together 13.03× more often than chance (946 co-occurrences in the same test; lift≥1.3, n≥300).

Lift = how many times more often both groups appear on the same test than if independent. Thresholds: lift ≥ 1.3, co-occurrences ≥ 300.

Is low mileage better for a Mercedes C Class?

Cars driven under 5,000 miles a year stands out at 12.0%, against 20.9% for cars driven 8,000–12,000 miles a year.

higher = larger sharecompare shares in percentage points

BandFail %Tests
<5k miles/year11.96%67,642
8–12k miles/year20.93%183,890
Gap (low − normal)-8.97 pp
By fuel and age

Diesel

AgeLow-use fail %nNormal fail %nGap pp
56.352,23712.437,127-6.08 pp
69.982,81614.7510,695-4.78 pp
710.394,95816.5619,262-6.17 pp
810.893,84618.1518,545-7.25 pp
913.573,17620.1119,108-6.54 pp
1012.672,69123.3916,356-10.71 pp
1116.632,05030.7313,756-14.09 pp
1220.082,19632.2115,806-12.13 pp
1319.841,73933.1611,894-13.32 pp
1420.951,06937.326,064-16.36 pp

Petrol

AgeLow-use fail %nNormal fail %nGap pp
58.646,41512.626,846-3.98 pp
68.376,34214.016,459-5.64 pp
78.376,15416.825,499-8.45 pp
89.543,97115.763,934-6.22 pp
910.922,84720.873,042-9.95 pp
1010.612,44123.651,818-13.04 pp
1115.582,74128.272,179-12.69 pp
1216.183,61030.962,826-14.79 pp
1317.842,28230.122,035-12.29 pp
1421.082,29135.062,199-13.98 pp

At matched ages 5–14, cars averaging under 5k miles/year fail at 12.0% vs 20.9% for 8–12k miles/year — 9.0 pp lower (n_low=67,642, n_normal=183,890). In this family low annual use is associated with fewer MOT fails, not more — the ‘garage queen’ penalty is not visible in overall fail rates. Diesel alone: 13.0% low-use vs 21.6% normal (-8.6 pp).

Mercedes C Class real MPG against official fuel economy

petrol/electric (2023) real-world fuel use stands out at +493%, against 0% for an exact match to the official figure.

higher = larger sharecompare shares in percentage points

On-board meters against the official test, by cohort
YearFuelRealOfficialGapVehicles
2021diesel7.16 l6.16 l+16.18%137,711
2021diesel/electric6.01 l1.39 l+331.72%47,220
2021petrol9.65 l8.09 l+19.25%74,866
2021petrol/electric5.85 l1.47 l+298.22%51,849
2022diesel7.21 l6.2 l+16.37%125,656
2022diesel/electric6.32 l1.33 l+376.11%29,011
2022petrol9.24 l7.79 l+18.66%70,550
2022petrol/electric5.98 l1.32 l+352.41%33,293

Since 2021 every new car in Europe records its own fuel use, and the regulator publishes what those meters say next to the laboratory figure the car was sold on. For this manufacturer the worst gap is 20.6% — petrol cars of 2023 burning 9.6 litres per 100 km against an official 7.96, with CO₂ higher by the same proportion.

This is the manufacturer, not the model. The regulator aggregates by legal manufacturer (MERCEDES-BENZ AG), so these figures are context for the badge rather than a measurement of this particular car — a point we would rather state plainly than let a reader assume otherwise. The gap itself is not a scandal, it is the known distance between a standardised laboratory cycle and real roads, but it is the distance you actually pay for at the pump. The plug-in hybrid rows are not a data error and deserve a sentence of their own: an official figure of 1.39 litres assumes the car spends most of its life on the battery, and the meters say these ones burned 6.01. Owners are not plugging them in, and a plug-in hybrid that is never charged is simply a heavy petrol car. Source: European Environment Agency (EEA), Real-world CO2 emissions from new cars and vans, reporting year 2024, v3, 2023_Cars_Aggregated.csv, CC BY 4.0 — copyright holder: European Environment Agency (EEA).

Which Mercedes C Class engine is best?

diesel 1.5–1.8 is highest at 113.3; petrol over 2.0 is lowest at 80.2 — the gap is 33.1 points.

below 100 is betterabove 100 is worse100 = normal for this model at that age

Engine bands against this model's own failure rate at the same ages
FuelCapacityvs own age normRaw fail %Tests
petrolover 2.0 litre80.215%39,406
petrol1.8–2.0 litre93.515.86%61,593
petrol1.5–1.8 litre95.532.45%93,205
petrol1.2–1.5 litre97.110.97%20,392
diesel1.8–2.0 litre100.311.03%30,896
dieselover 2.0 litre10424.82%349,570
diesel1.5–1.8 litre113.319.06%12,547

Splitting this model by fuel alone hides the thing that actually differs. Within the same badge, the diesel 1.5–1.8 runs at 113.3 against this model's own age norm while the petrol over 2.0 runs at 80.2 — a spread of 33.1 points between two cars that share a name.

Read this one with more care than the rest of the page. Age is held constant, but who buys which engine is not: the largest capacity in a range is often a performance or executive variant that is garaged, cherished and lightly driven, while the smallest is frequently a fleet or entry car worked hard from new. The gap below is real in the test records; how much of it is the engine and how much is the owner, this data cannot separate. Bands under 5,000 tests are not shown.

Best year for a Mercedes C Class, and the years to avoid

Build year 2004 is highest at 108.5; Build year 2019 is lowest at 88.7 — the gap is 19.8 points.

below 100 is betterabove 100 is worse100 = normal for this model at that age

build year vs the same model at the same age · 100 = as expected

Mercedes C Class build year vs the same model at the same age · 100 = as expected — 2024 UK MOT data
Mercedes C Class by build year, tests 2019–2024. Below 100 is better than the model's own age norm.
Every build year with its confidence interval
Build yearvs own age norm95% CIRaw fail %TestsVerdict
202091.287.6–94.810.75%22,530better
201988.787–90.411.11%97,889better
201892.190.7–93.412.38%144,248better
201793.792.7–94.713.39%253,618better
201699.198.1–10015.44%262,803no different
201599.498.5–100.417.49%241,080no different
201496.395.2–97.319.44%168,868better
2013106.8105.7–107.924.48%156,584worse
2012108107–108.927.18%187,207worse
2011102101–10328.03%145,807worse
2010102.6101.5–103.731.07%101,660worse
2009101.9100.8–10333.62%92,470worse
200899.698.5–100.735.21%94,544no different
2007102.8101.6–103.938.4%83,379worse
2006104.6103.4–105.840.81%68,806worse
2005106.9105.6–108.143.05%63,730worse
2004108.5107.1–109.944.39%50,943worse
2003106.2104.6–107.843.66%38,170worse
2002100.798.6–102.840.75%20,948no different
200199.696.3–102.940.44%8,626no different
200093.588.9–98.137.8%4,182better

The best build year here is 2019 and the weakest is 2004. Comparing build years sounds simple and is not: within a single year of testing, a car's build year and its age are the same number, so a naive comparison of years is a comparison of ages wearing a disguise. Each year below is measured against the same model at the same age in other cohorts, across six years of testing — 16 of 21 years come out distinguishable from their own model's age norm.

Two limits worth knowing before you act on this. Age, test year and build year are locked together by arithmetic, so the test-year effect is taken from the observed national failure level of each year rather than estimated — it is an adjustment, not a solution. And for cars built before about 2005, a good score says more about which examples survived to be tested than about how that year was built: survivors are self-selected for care.

Mercedes C Class MOT repair costs

The MOT-failure repair budget per test runs from £109.29 to £207.65, against £54.85 for the test itself.

bigger number = costs morepounds per test, MOT-failing faults only

MOT repairs, budget
£109–208
per test, repairs only
The test itself
£54.85
statutory cap, unchanged since 2010
How the figure is built: chance of failing × typical price of that repair
ComponentFails per 100 testsTypical repairIts priceContribution
Suspension27.5 (nat. 19.9)Suspension coil spring (single corner)£180£49.50
Brakes14.1 (nat. 14.34)Front brake pads (parts + labour, typical hatchback)£150£21.15
Lamps, reflectors and electrical equipment12.7 (nat. 23.52)Battery replacement (standard 12V lead-acid)£140£17.78
Tyres13.4 (nat. 10.27)Tyre (single mid-range 16" fitted)£90£12.06
Noise, emissions and leaks4.4 (nat. 4.9)Exhaust rear silencer£200£8.80

Multiply how often each component fails on this model by what that repair usually costs, and you get the amount an owner should expect to budget per test for MOT-failing faults only — roughly £109 to £208, on top of the test fee itself. It is a budgeting figure, not a quote: the spread between a set of pads and a set of discs is most of the range.

Prices are modal quotes from a hand-kept catalogue of published UK garage guides — we do not scrape the booking sites, their terms forbid it, so this list is short and updated by hand with a source and date against each line. Each line prices one typical repair in that group, not a full remedy, and only groups our catalogue actually covers are counted. The contrast worth noticing is the second card: the legal maximum for the test has been £54.85 since 2010, while the repairs it uncovers have followed inflation the whole time.

For scale from a different direction: Warrantywise, which sees used-car warranty claims rather than test failures, puts the average claim at £2,052 across the ten highest-claim models it ranks and £539 for Honda, the lowest-claim make in its index (Warrantywise index 2026, 1.6 million claims, cars aged 3–15). Those sit an order of magnitude above the figures in this table, and the gap is the point: a warranty claim is a gearbox or an engine, which almost never fails an MOT, while the faults that do fail one are corrosion, lamps and tyres, which no warranty pays for. The two numbers answer different questions and neither replaces the other.

Mercedes C Class running costs for a fleet

Vehicles failing at age 10 stand out at 21%, against 11% at age 5 in the same 100-vehicle fleet.

higher = larger sharecompare shares in percentage points

Fails per 100 at age 5
11
vehicles needing work
At age 10
21
same fleet, five years on
Repairs per 100
£10,929
plus £5,485 in test fees
Off the road
1d
median; 38.98% cleared same day
Failure rate and typical odometer by age
AgeFailsMedian odometerTestsGap vs age 5
39.98%24,5793,446-0.9 pp
49.79%30,73514,765-1.1 pp
510.84%37,73347,662+0.0 pp
612.5%47,14055,173+1.7 pp
714.61%56,74676,338+3.8 pp
816.04%68,30169,290+5.2 pp
918.68%79,71760,915+7.8 pp
1020.52%85,44545,816+9.7 pp
1126.91%91,47441,462+16.1 pp
1228.75%97,93646,853+17.9 pp
1329.18%105,95333,769+18.3 pp
1431.63%107,10022,551+20.8 pp
1533.29%115,90222,240+22.4 pp
1634.49%118,14723,698+23.7 pp
1737.19%115,08619,896+26.3 pp
1840.53%113,73715,461+29.7 pp
1941.28%118,15213,822+30.4 pp

The number a fleet manager needs is not the failure rate, it is the year the car starts costing more. Between age 10 and 11 the failure rate of this model jumps by 6.39 percentage points — the steepest single step in its life, and the natural planning point for replacement.

Repair spend uses the same modal prices as the section above, so it inherits the same limits: one typical repair per component group, not a full remedy. Downtime is the gap between the failed test and the passed re-test, which is the window a vehicle is legally off the road.

Mercedes C Class rust problems: where they corrode

Age-standardised corrosion susceptibility stands out at 1.75×, against for the national age-standardised rate.

above 1.0× = rusts more than averagebelow 1.0× = rusts less

How it rusts
1.75×
1.86% of tests record a corrosion defect vs 1.07% typical — age-standardised
Salt Belt exposure
13th
percentile among the models published here, from its tests across 113 postcode areas

This Mercedes C Class fails on corrosion far more often than average once age is held constant, and its owners live in areas that are gentler than most for the models we publish. Those two point in opposite directions, which is the informative case: it rusts more than average despite living in gentler places, so the cause is the car, not the postcode.

Corrosion is the one failure mode that is as much about geography as about the car. We keep the two apart on purpose: a model can look rusty simply because it is popular in Scotland, and a model can look clean simply because it is bought in Surrey. Blending them into a single score would hide which of the two is doing the work.

Exposure is this model's tests weighted by an area corrosion index built from frost days, salt load and distance to the coast — the composite validated at r = 0.42 against corrosion defects we actually record. It is published as a rank, not a raw score, because every mainstream model skews towards low-corrosion areas for the simple reason that most of Britain's cars are in the south. Susceptibility is standardised to the national age profile, so an old fleet does not get labelled a rusty model.

Does a Mercedes C Class advisory become a failure?

Lamps, reflectors and electrical equipment are highest at 25.3%; Identification of the vehicle is lowest at 2.6% — the gap is 22.7 percentage points.

higher = more likelypercentage is the observed transition probability

chance the same component fails at the next MOT, given an advisory now

Mercedes C Class chance the same component fails at the next MOT, given an advisory now — 2024 UK MOT data
Mercedes C Class, advisory → failure conversion by component group, chained tests 2019–2024. Chart labels and rates: Lamps & electrical 25.3% · Suspension 23.8% · Brakes 11.7% · Steering 10.6% · Tyres 10% · Visibility 9.3% · Noise, emissions, leaks 7.6% · Body & chassis 6.2%.
Advisory today → failure at the next test, with how long you have
ComponentFails next timeTypical lead timeMiles of warningAdvisories tracked
Lamps, reflectors and electrical equipment25.3%12 months4,56415,101
Suspension23.8%12 months5,876178,319
Brakes11.7%12 months5,948334,639
Steering10.6%12.1 months4,88210,122
Tyres10.0%12 months6,867385,864
Visibility9.3%12 months6,5401,193
Noise, emissions and leaks7.6%12.1 months5,70137,179
Body, chassis, structure6.2%12.1 months4,81526,580
Seat belts and supplementary restraint systems5.3%12 months4,7883,823
Identification of the vehicle2.6%12.1 months6,77422,883

This is the question an advisory note actually raises, and it needs six years of test history to answer. We followed the same vehicles from one MOT to the next across 2019–2024 and measured how often a component that was merely advised came back as a genuine failure at the next test.

Read it as a budgeting horizon, not a prophecy: the most likely component above turns into a failure for about 25 in 100 cars, and the median gap is 12 months and roughly 4,564 miles. The rest were repaired, sold, scrapped, or simply held. Rows with fewer than 500 tracked advisories are not shown.

What will fail next on a Mercedes C Class?

Suspension after a failure at age 15-19 is highest at 29.5%; Brakes after a passed at age <3 are lowest at 1.1% — the gap is 28.4 percentage points.

higher = more likelypercentage is the observed transition probability

Probability of each component failing at the next test, by age and last result
AgeLast testMost likely next failuresCars tracked
<3passedTyres 5.5% · Visibility 2.9% · Brakes 1.1%73,674
<3advisoryTyres 6.9% · Visibility 4.2%22,791
<3failureTyres 7.1% · Visibility 4.7%11,464
3-5passedTyres 5.9% · Visibility 3.0% · Suspension 2.2%281,531
3-5advisoryTyres 8.2% · Visibility 4.5% · Suspension 3.2%120,437
3-5failureTyres 9.0% · Visibility 5.1% · Suspension 3.9%65,728
6-8passedSuspension 6.4% · Tyres 5.9% · Brakes 4.0%208,269
6-8advisorySuspension 8.8% · Tyres 8.6% · Brakes 6.5%121,009
6-8failureSuspension 11.1% · Tyres 9.7% · Brakes 8.4%86,121
9-11passedSuspension 14.0% · Brakes 7.2% · Tyres 5.6%109,296
9-11advisorySuspension 19.3% · Brakes 11.1% · Tyres 8.2%88,152
9-11failureSuspension 21.8% · Brakes 14.1% · Lamps, reflectors and electrical equipment 10.2%82,654
12-14passedSuspension 18.3% · Lamps, reflectors and electrical equipment 9.3% · Brakes 7.3%56,615
12-14advisorySuspension 24.8% · Lamps, reflectors and electrical equipment 12.9% · Brakes 11.3%56,255
12-14failureSuspension 27.6% · Lamps, reflectors and electrical equipment 17.3% · Brakes 13.9%65,124
15-19passedSuspension 18.6% · Lamps, reflectors and electrical equipment 11.2% · Brakes 6.8%40,076
15-19advisorySuspension 26.4% · Lamps, reflectors and electrical equipment 17.1% · Visibility 11.0%52,328
15-19failureSuspension 29.5% · Lamps, reflectors and electrical equipment 22.2% · Brakes 14.1%66,242
20+passedSuspension 8.8% · Lamps, reflectors and electrical equipment 8.3% · Visibility 5.8%9,479
20+advisorySuspension 15.3% · Lamps, reflectors and electrical equipment 15.0% · Visibility 10.7%10,968
20+failureLamps, reflectors and electrical equipment 20.5% · Suspension 18.2% · Visibility 12.8%10,186

The same chains, cut differently: given a car's age and how its last test went, which component most often causes trouble at the following one.

The pattern that repeats across every family: a failure at one test roughly doubles the chance of a failure on the same component at the next one, and an advisory sits about half-way between a clean pass and a failure. Age bands in years; probabilities are per car, not per defect item.

Mercedes C Class ownership: what six years of MOTs show

The ten-day re-test pass rate is highest at 57.5%; The later re-test pass rate is lowest at 3.5% — the gap is 54.0 percentage points.

higher = larger sharecompare shares in percentage points

Fixed same day
38.98%
of failures re-tested
Fails /10k miles
0.34
miles actually driven
Clean streaks
38.39%
3+ tests, nothing noted
Odometer anomaly
1.55%
reading went backwards

Failing is usually a same-week event, not a disaster. Of 375,764 failures followed through to their re-test, 38.98% were repaired and passed the same day and 57.53% within ten days; the median gap is 1 day. 861,453 defect items were cleared in the process.

Per mile driven, not per year. Dividing failures by the miles that actually went onto the odometers between consecutive tests gives 0.34 failures per 10,000 miles, on a median of 6,033 miles a year across 417,460 chains. This is the number to compare between models — an annual rate quietly rewards cars that barely leave the drive.

Two populations hide inside one model. 38.39% of these cars strung together three or more tests with nothing recorded at all, while 27% carried the same advisory three times or more — the same fault, noted, ignored, noted again. When you buy used you are buying one of those two histories, and the MOT record shows which.

Odometer anomalies: 1.55% of 417,847 chains show a reading lower than the previous test, with a median drop of 35,161 miles. We call this an anomaly and not fraud on purpose — instrument swaps, imports, unit mix-ups and keying errors all land in the same bucket. Obvious typos (drops under 100 miles or over 90% of the reading) are already excluded.

Mercedes C Class safety recalls and how to check yours

DVSA recall campaigns stand out at 158, against 4.86 campaigns per 10,000 licensed cars after fleet size is accounted for.

bigger number = more recorded casescompare like-for-like scope, not sample size alone

recall campaigns launched per year

Mercedes C Class recall campaigns launched per year — 2024 UK MOT data
Campaigns launched per year for the Mercedes C Class. Source: DVSA vehicle safety recalls. Chart values: 2010: 1 · 2011: 0 · 2012: 0 · 2013: 0 · 2014: 1 · 2015: 1 · 2016: 0 · 2017: 1 · 2018: 1 · 2019: 0 · 2020: 0 · 2021: 3.
Most recent safety recall campaigns for the Mercedes C Class
ReferenceLaunchedVehiclesConcern
R/2021/37629/11/202150,390The behaviour of the emergency call system might not meet specifications.…
R/2021/08230/03/202124The communication module may be deactivated…
R/2021/08330/03/202136The software of certain communication modules may not meet specifications.…
R/2018/14630/07/201821,366The seat backrests on the right side of the front seats in the c-class Coupe/Convertible and E-Class Coupe/Convertible may not fully lock.…
R/2016/29830/01/20175The threaded connection on the Adblue filler pipe and ground cable for the fuel tank access may not be correctly tightened on vehicles with diesel engine OM651.…
All 8 campaigns
ReferenceLaunchedBuild datesVehiclesConcern
R/2021/37629/11/202104/01/2016 – 29/01/202150,390The behaviour of the emergency call system might not meet specifications.…
R/2021/08230/03/202103/05/2016 – 02/07/202024The communication module may be deactivated…
R/2021/08330/03/202103/02/2017 – 11/03/202036The software of certain communication modules may not meet specifications.…
R/2018/14630/07/201801/08/2017 – 01/02/201821,366The seat backrests on the right side of the front seats in the c-class Coupe/Convertible and E-Class Coupe/Convertible may not fully lock.…
R/2016/29830/01/201701/08/2015 – 30/09/20155The threaded connection on the Adblue filler pipe and ground cable for the fuel tank access may not be correctly tightened on vehicles with diesel engine OM651. It is possible for the connection to work loose and fail th…
R/2015/14930/07/201502/06/2014 – 02/06/201410The threaded connections to the rear of the front seats may not have been tightened correctly. In the case of a serious vehicle accident the seat connection may not function as designed resulting in an elevated risk of i…
R/2014/11330/09/201417/01/2014 – 22/09/20148,140It is possible that the steering column coupling lock may not have been installed correctly. The driver will recieve warning of the issue by noise. However in extreme circumstances it is possible that steering control of…
R/2010/15029/11/20104Some vehicles may have been fitted with incorrect specification brake discs. This in extreme cases may have an affect on the brake efficiency should the vehicle have to carry out an emergency stop.…

DVSA lists 158 safety recall campaigns for the Mercedes C Class — 4.86 campaigns per 10,000 of these cars licensed in Great Britain, covering roughly 79,975 vehicles in total. A recall is the manufacturer fixing a fault for free, so an open recall on your car costs nothing to clear.

Counter-intuitive, and measured on our own data: across the 25 families published here, more recalls go with a lower MOT Risk Index (r = −0.52). Heavily recalled models are not worse cars in the test bay — an active manufacturer removes the fault before it becomes an MOT failure.

Check whether a specific car has an outstanding recall — free, by registration — at DVSA's recall service. Source: DVSA vehicle safety recalls (check-vehicle-recalls.service.gov.uk), OGL.

Mercedes C Class technical service bulletins: what dealers are told

NHTSA manufacturer communications are 777.

bigger number = more recorded dealer communicationsnot affected vehicles or confirmed faults

These are the issues the manufacturer fixes quietly: service communications sent to dealers without a public recall campaign. They show what the service network has been told even when the issue never became news.

United States · NHTSA manufacturer communications

US technical service bulletins by communication year; leading subjects cover the full file
Communication yearBulletinsLeading subjects across all years
20121
  • Electrical system (299)
  • Equipment (137)
  • Engine (90)
  • Powertrain (56)
  • Steering (45)
  • Structure (45)
  • Engine and cooling (41)
  • Exterior lighting (37)
201316
201443
201543
201645
201745
201849
201950
202034
202139
202241
202343
202498
2025149
202681

Caveat worth stating plainly: this is NHTSA data about US-specification cars. British cars sold under the same name often use different gearboxes, engines and equipment, so a bulletin may describe a component that was never fitted here. The file counts dealer communications, not affected vehicles or confirmed failures, and it cannot tell you whether an individual UK car has the issue. A communication can carry more than one subject tag, so topic counts do not have to add up to the total. Source: NHTSA Manufacturer Communications API (US-market vehicles; queried model years 2015-2022). Licence: U.S. Government work / public domain · retrieved 2026-08-03.

Mercedes C Class owner complaints: what goes wrong

Engine (not MOT-tested) is highest at 396; Transmission (not MOT-tested) is lowest at 78 — the gap is 318.

bigger number = more recorded casescompare like-for-like scope, not sample size alone

Owner complaints (US) against actual MOT failures (UK) for the same component groups
ComponentComplaintsShareMOT fail items per 100MOT rankAgreement
Engine (not MOT-tested)39630.8%not in top 6complained about, rarely an MOT failure
Lamps & electrical17213.4%12.7#4complained about, fails occasionally
Body & structure15912.4%not in top 6complained about, rarely an MOT failure
Restraints1038.0%not in top 6complained about, rarely an MOT failure
Steering826.4%not in top 6complained about, rarely an MOT failure
Transmission (not MOT-tested)786.1%not in top 6complained about, rarely an MOT failure

Two different populations answering two different questions: the MOT records what an inspector can measure once a year, the complaint file records what annoyed or frightened an owner on the road. A component high in one column and absent from the other is the interesting case — driver-assistance and electronics dominate complaints while almost never appearing as an MOT failure item.

What the reports actually say
2017 Mercedes c300 the switchover valve in the diagnostic module of the evaporative emission control system is jammed open. This issue was called for recall for models 2018 or later, but 2017 was not part of it.
NHTSA complaint, filed 07/27/2026 · ENGINE
UNKNOWN it was just one day I started my car and turned the A/C on and I started getting this strong gasoline smell. I went on like a saw there is a recall for this problem for the M274 engines.
NHTSA complaint, filed 12/31/2025 · FUEL/PROPULSION SYSTEM

US owners have filed 1,286 complaints about the equivalent Mercedes C Class to the National Highway Traffic Safety Administration, including 44 that mention a crash, 9 a fire and 42 an injury. These are owner reports, not verified findings — but they are the only large public record of what drivers themselves notice, and they cover the years between MOT tests.

Caveat worth stating plainly: US-specification cars, self-selected reporters, no denominator — complaint counts scale with how many cars were sold there and how motivated owners are to file. The mechanical gap matters as much as the statistical one: American cars of the same name often carry different gearboxes, engines and equipment — automatics where Britain buys manuals — so a drivetrain complaint filed in Ohio may describe a part that was never fitted here. Read the ranking inside a model, not between models, and treat drivetrain entries with particular caution. Source: NHTSA ODI consumer complaints (US market, public domain) — US-spec vehicles, indicative only.

Mercedes C Class inspection results in other countries

United Kingdom MOT stands out at 22.6%, against 26.0% nationally.

higher = larger sharecompare shares in percentage points

Same model, different national inspection regimes
CountryTestThis model failsNational averagePositionSample
United KingdomMOT (class 4)22.55%26.01%-3.5 pp646,907
NetherlandsAPK48.4%50.9%-2.5 pp47,418
NorwayPKK35.6%33.5%+2.1 pp4,363

The countries disagree about this car, and that is worth saying out loud rather than averaging away. A model can sit above its national average in one country and below it in another because the fleets are not the same cars: different model years, different engines, different roads and salt, and inspection rules that weight components differently. Treat each row as evidence from one regime, not as a verdict.

The exact faults Netherlands records — APK defect codes, 2024
CodeFaultRecordedType
210Tyre pressure not at the correct value7,427failure
205Tyre with insufficient tread6,331failure
AC1Tyre down to 1.6–2.5 mm of tread3,927advisory
AC4Steering or suspension ball joint worn up to 1.0 mm3,444advisory
516Dipped headlight incorrectly aimed3,410failure
186Ball joint with excessive play2,454failure
RA2Excessive leak of other fluids1,883advisory
203Tyre damaged1,695failure

Worth dwelling on how mundane the top of that list is: tyre pressure, tread depth, headlight aim. The Dutch APK records 1.086 defects per inspection against a much higher national failure rate than Britain's, and the reason is not that Dutch cars are worse — it is that the two regimes draw the line between "note it" and "fail it" in different places. Codes are the RDW's own; the English wording here is our translation of the Dutch original.

Britain is not the only country that inspects every car every year, and the Mercedes C Class is on the road in all of them. Each national regime writes its own rules, so the pass rates below are not comparable to each other — what does travel across a border is whether a model sits above or below its own country's average.

Rows with fewer than 500 inspections are not published. Sources: RDW open data — Meldingen Keuringsinstantie + Geconstateerde Gebreken + Gekentekende voertuigen (2024), CC0. Not an RDW endorsement.; Statens vegvesen — Periodisk kjøretøykontroll (PKK) 2024, CC BY 4.0.

Mercedes C Class MOT: quick answers

Mercedes C Class MOT Risk Index stands out at 83.6, against 100 for a car with the same age profile.

below 100 is betterabove 100 is worse100 = normal for this model at that age

What is the Mercedes C Class first-time MOT pass rate?
77.45% of first attempts passed in 2024 (646,907 tests). This is the first-time figure: retests after repair are excluded. Basis: first-time, excluding retests.
Why does this number differ from other sites?
Other sites often report a pass rate that includes retests or counts all attempts. Our 22.55% figure is the first-time initial failure rate, using 646,907 primary tests as the denominator (first-time, excluding retests). The age-adjusted MOT initial-failure ratio 83.6 is shown separately because raw rates compare fleet age as well as cars.

Compare the Mercedes C Class with other cars

Honda e is highest at 84.6; Mercedes C Class is lowest at 83.6 — the gap is 1.0 points.

below 100 is betterabove 100 is worse100 = normal for this model at that age

Head-to-head

BMW 3 Series head-to-headAudi A4 head-to-headTesla Model 3 head-to-head

Same brand

All Mercedes-Benz MOT statisticsMercedes A Class MOT statsMercedes E Class MOT stats

Similar risk

Land Rover Defender (index 84.4)Audi A4 (index 84.6)Honda e (index 84.6)

Same size class

how Audi A3 compareshow Toyota Yaris compareshow BMW 3 Series compares


Data details & how to cite

Scope: class-4 vehicles (cars), initial tests only, outcomes pass / fail / fixed-on-the-spot at the station (PRS counts towards the failure rate — the defect was present at arrival). Index = observed initial failures ÷ failures expected for this fleet's exact age profile, ×100; margin of error is a 95% confidence interval. Covers ALL generations together — a 3-year-old and a 15-year-old are very different cars; a generation split is on the roadmap. Dataset release dataset_release_id=dvsa-2024-v1, frozen baseline; headline claim_id=family-stats:mercedes-c-class:dvsa-2024-v1. Full method: methodology.

Cite: MOT Risk Index (2026). Mercedes C Class MOT statistics 2024 (dvsa-2024-v1). https://motriskindex.co.uk/cars/mercedes-c-class/ · Published 2026-07-30.