Mercedes-Benz 320 — MOT statistics 2024

The Mercedes-Benz 320 failed 30.63% of 493 first MOT attempts in 2024 ("first-time", excluding retests). Adjusted for the age of the fleet, its initial-failure ratio is 77.3 (100 = expected for its age profile). This car fails its MOT about 23% less often than expected for its age. Small sample — treat with care.

Age-adjusted peer: Mazda RX-8 (index 77.4) — the two published results are 0.1 index points apart.

Mercedes-Benz 320 common problems: what actually fails the MOT

Lamps, reflectors and electrical equipment are well below the reference at 21.2 per 100 tests, against 34.0 per 100 tests across UK vehicles of the same ages.

higher bar = fails more oftenrate per 100 tests

family vs national — matched to UK vehicles of the same ages — top component groups, per 100 tests. Legend: This family · National avg. Combined labels: family / national average. A gap here reflects how these vehicles are driven, used and maintained as well as how they were built — an MOT defect is a test outcome, not a breakdown.

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

Mercedes-Benz 320 MOT advisories: what gets flagged

Brakes are highest at 53.8 per 100 tests; Non-component advisories are lowest at 5.4 per 100 tests — the gap is 48.4 per 100 tests.

higher bar = flagged more oftenadvisory items per 100 initial tests

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

If a car like this fails, does it fail again?

A failure rate does not say whether a failure is a one-off or the start of something. This follows the same vehicles into their next ordinary MOT a year later — retests after a repair are excluded, because they follow a failure by definition. 2019-2024.

A failed test does not clearly change next year's odds here (30.5% against 26.0%): the difference is within the margin of error. The failure most likely to come back is lamps, reflectors and electrical equipment — 26.9% of those vehicles fail again next year. Some of this is the vehicle and some is the owner: a car that was let go once tends to be let go again. One caveat: a car that fails may be sold or scrapped rather than tested again, so these figures describe the vehicles that came back.

Adjusted for how much these are actually driven

The headline index adjusts for the fleet's age. Wear, though, follows mileage: a three-year-old taxi and a three-year-old garage queen sit in the same age band. These two rows compare every car with vehicles of the same age, and then with vehicles of the same age and the same annual mileage, 2019-2024, on 2,605 tests. Both stand on the six-year corpus so they are measured on identical data — compare them with each other, not with the headline index above, which is measured on 2024 alone.

Mileage matters here: matching on how much these are driven moves the figure by 4.2 points — this fleet works harder than the vehicles it is measured against, so the age-only view penalises it — but it does not change which side of normal the car sits on. One limit to keep in mind: mileage is partly a result of how often a car breaks down — one that spends weeks in the workshop covers fewer miles — so the mileage-matched figure can understate a real weakness. Tests with no usable odometer reading are left out of it.

How the Mercedes-Benz 320 compares with cars of its own age and size

Not against the whole fleet — against cars of the same size class tested at the same age, 2019-2024.

Raw first-time failure rates within each age, so fleet age cannot flatter either side. A positive difference means this model fails more often than its own class at that age.

How does the Mercedes-Benz 320 perform as it gets older?

The 320 at age 20 is well below the reference at 30.7%, against 41.0% for all vehicles of the same age.

higher = larger sharecompare shares in percentage points

Chart axes: car age, years · failure-rate scale 0–47%.

Takeaway: solid line: this family; dashed: all cars.

How dangerous are Mercedes-Benz 320 MOT failures?

Major defects stand out at 63.1 per 100 tests, against 52.8 per 100 tests nationally.

higher bar = fails more oftenrate per 100 tests

Chart values: Minor 16.9 · Major 63.1 · Dangerous 11.5.

Per 100 tests on this family. National average: Minor 14.2 · Major 52.8 · Dangerous 11.2 per 100.

Does the month of a Mercedes-Benz 320 MOT matter?

Nov is highest at 37.1%; Apr is lowest at 24.6% — the gap is 12.5 percentage points.

higher = larger sharecompare shares in percentage points

Chart scale: 23%–39%.

bars: Mercedes-Benz 320 · dashed: all class-4 cars

Takeaway: the spread between best and worst month is 12.5 percentage points — noticeable seasonality. 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 18.9% of these cars were first registered in March with another17.1% in September — 36% 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. That shapes how many cars are tested each month — not how often they fail: the busiest months here are not the worst ones, so read the failure line on its own and the volume behind it separately.

Mercedes-Benz 320 average mileage by age

At age 20+, the middle half of 320s runs from 80,960 miles to 142,628 miles, against 105,211 miles as the median.

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

Does high mileage mean more Mercedes-Benz 320 MOT failures at the same age?

Within the same age group, split by odometer (2024 MOTs), so this separates wear from age: at ages 15+, 28.9% of those with 70,000–100,000 miles failed first time versus 40.5% of those with over 140,000 miles.No clear mileage gap inside this age group, among cars still being tested.

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

A typical 20+-year-old 320 has ~105,211 miles on the clock. Much more — ask why; much less — check for gaps in the MOT history.

Where in Britain the Mercedes-Benz 320 fails its MOT most

Too few tests in any single postcode area to name one, so this is the wider picture across 2,771 tests, 2019-2024.

Raw pass/fail rates, not age-adjusted: fleets differ by region. England is split north of Sheffield, between Sheffield and Oxford, and south of it.

How many miles does a Mercedes-Benz 320 last?

100,000+ miles is highest at 65.0%; 150,000+ miles is lowest at 25.7% — the gap is 39.3 percentage points.

higher = larger sharecompare shares in percentage points

Of 2,761 tests of this family with a usable odometer in 2024, 65.0% had reached 100k miles, 25.7% had reached 150k miles. This is a cross-section of cars still presenting for MOT, not a full birth cohort.

Mercedes-Benz 320 faults that come together

Lamps & electrical + Seatbelts & SRS stand out at 4.46×, against 1.00× if the faults were independent.

above 1.0× = more than expectedbelow 1.0× = less

Defects in «Lamps, reflectors and electrical equipment» and «Seat belts and supplementary restraint systems» appear together 4.46× more often than chance (24 co-occurrences in the same test; 66 pairs compared).

Lift = how many times more often both groups appear on the same test than if independent. A pair is listed from 5 tests with both faults; the lift is shown from 20, and called above chance only when its 95% interval excludes 1 (see rough estimates).

Mercedes-Benz 320 MOT repair costs

The MOT-failure repair budget per test runs from £105.87 to £201.15, against £54.85 for the test itself.

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

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 £106 to £201, 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-Benz 320 rust problems: where they corrode

Age-standardised corrosion susceptibility stands out at 10.79×, against 1.00× for the national age-standardised rate.

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

This Mercedes-Benz 320 fails on corrosion far more often than average once age is held constant, and its owners live in areas that are about typical 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-Benz 320 advisory become a failure?

Brakes stand out at 11.9%.

higher = more likelypercentage is the observed transition probability

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 12 in 100 cars, and the median gap is 12.2 months and roughly 6,000 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-Benz 320?

Suspension after a failure at age 12-14 is highest at 26.1%; Suspension after a passed at age 20+ is lowest at 4.8% — the gap is 21.4 percentage points.

higher = more likelypercentage is the observed transition probability

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-Benz 320 ownership: what six years of MOTs show

The ten-day re-test pass rate is highest at 70.9%; The later re-test pass rate is lowest at 5.6% — the gap is 65.3 percentage points.

higher = larger sharecompare shares in percentage points

Failing is usually a same-week event, not a disaster. Of 554 failures followed through to their re-test, 23.47% were repaired and passed the same day and 70.94% within ten days; the median gap is 2 days. 1,443 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 0.691 failures per 10,000 miles, on a median of 2,521 miles a year across 687 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. 25.95% of these cars strung together three or more tests with nothing recorded at all, while 26.47% 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: 5.739% of 697 chains show a reading lower than the previous test, with a median drop of 48,734 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-Benz 320 MOT: quick answers

Mercedes-Benz 320 MOT Risk Index is well below the reference at 77.3, 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-Benz 320 first-time MOT pass rate?

69.37% of first attempts passed in 2024 (493 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 30.63% figure is the first-time initial failure rate, using 493 primary tests as the denominator (first-time, excluding retests). The age-adjusted MOT initial-failure ratio 77.3 is shown separately because raw rates compare fleet age as well as cars.

Compare the Mercedes-Benz 320 with other cars

Mazda RX-8 is highest at 77.4; Ford Mustang Mach-E is lowest at 77.1 — the gap is 0.3 points.

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

Same brand

All Mercedes-Benz MOT statisticsMercedes-Benz M-Class MOT statsMercedes-Benz GLS MOT stats

Similar risk

Mazda RX-8 (index 77.4)Ford Mustang Mach-E (index 77.1)Mercedes-Benz M-Class (index 77.1)

Same size class

how Honda Freed compareshow Chevrolet Camaro compareshow Nissan Silvia compares

By failure group

Mercedes-Benz 320 body, chassis and structure failuresMercedes-Benz 320 brakes failuresMercedes-Benz 320 lamps, reflectors and electrics failuresMercedes-Benz 320 noise, emissions and leaks failuresMercedes-Benz 320 seat belts and airbags failuresMercedes-Benz 320 steering failuresMercedes-Benz 320 suspension failuresMercedes-Benz 320 tyres failuresMercedes-Benz 320 visibility failures