Common UK MOT failures by car age

The MOT trail of any UK car is a free public record of what's worn out, what's been advised and what's failed in each age band. Used carefully, the pattern in those records tells you what to expect from any car of that age — and where to budget your repair money.

These are the patterns based on DVSA-published data and the typical UK pass-rate distribution.

Pass-rate distribution by age

| Car age (years) | First-time pass rate | Severity of typical failures | |-----------------|---------------------|------------------------------| | 3 | ~90% | Mostly trivial — bulbs, washer fluid level | | 4–5 | ~80% | Brake-pad wear, tyre tread, washers | | 6–7 | ~72% | Brakes, headlight aim, suspension bushes starting | | 8–10 | ~65% | Suspension components, lower-arm bushes, exhaust corrosion | | 11–14 | ~58% | Structural rust on sills, exhaust, suspension top mounts | | 15+ | ~50% | Major corrosion, brake pipes, structural advisories |

These figures vary by make and segment — premium German cars typically pass at age 10 closer to the 70% mark; mainstream older diesels lower.

What fails at each age band

Age 3 (first MOT)

Trivial. The most common items are:

• Bulbs out — number plate, brake light, indicator
• Washer fluid level (yes, it's an MOT fail item)
• Tyre tread close to limit on rear tyres if the front pair has been swapped recently
• Indicator timing on cars where someone has fitted aftermarket LED bulbs without the correct resistor

Budget for the first MOT: typically just the £54.85 test fee plus maybe £10 for bulbs.

Age 4–6 (modern used)

The first signs of mainstream wear appear:

• Brake pads close to limit — the most common single failure item in this band
• Tyre wear — especially uneven wear pointing to alignment issues
• Headlight aim — surprisingly common after one or two parking knocks
• Wiper blades — dry, smearing or leaving streaks

Budget: £150–£300 to address typical advisories at this age.

Age 6–10 (used-market staple)

Suspension and brakes dominate:

• Anti-roll bar links worn — clunks over bumps
• Front lower-arm bushes going — vague steering, knocks
• Brake disc wear — replacement, not just pads, often needed
• Coil spring failures — particularly common in salt-belt regions
• CV boot splits — fail item, leads to joint failure if ignored

Budget: £300–£700 for the typical "needs work to pass" pre-MOT visit.

Age 10–14 (older used)

Corrosion makes its first major appearance:

• Sill corrosion — structural advisories, sometimes failures
• Exhaust corrosion — back box, mid-section, sometimes the manifold
• Suspension top mounts — clunks, rough ride, MOT advisories at first then failure
• Brake pipes corroded — particularly on Land Rover Defenders, older Range Rovers and any car driven through salt
• Subframe corrosion — Mazda RX-8 and certain Honda models infamously affected

Budget: £400–£1,200 depending on whether anything structural needs welding.

Age 15+ (older buy-and-cherish)

The "is it worth keeping" age band:

• Structural welding — sills, floor pans, suspension turrets
• Multiple advisory items carrying forward year on year
• Electrical gremlins — handbrake warning lights, ABS sensors, throttle position sensors
• Catalytic converter failures — particularly on cars where the cat is downstream of corroded exhaust pipework

Budget: highly variable. If the bodywork is sound, ongoing costs stay manageable. If structural rust starts, the economics often tip toward replacing the car.

What's special about diesel MOTs

Since 2018, the DVSA's smoke-opacity test for diesel cars is tighter. Particularly affected:

• DPF-equipped cars driven mostly on short trips — the DPF doesn't regenerate, fills up, fails the smoke test
• Older diesels with EGR-valve faults — emissions advisory, then failure
• Removed or "gutted" DPFs — a visual inspection now flags this and an MOT failure follows

If you're considering a diesel, the MOT history showing a sudden emissions failure followed by a quick same-day pass is worth asking about — DPF removal is illegal and a same-day fix usually means it.

What's special about EV MOTs

Fully-electric cars skip emissions and the engine-related items entirely. They still get tested for:

• Brakes — softer regen-led braking means brake wear arrives later
• Tyres — instant torque and higher kerb weight wear them faster
• Suspension and steering — same as ICE cars
• Lighting and signalling — same as ICE cars

EVs typically pass at age 3 above the 95% mark. Their first major issue is usually tyre-related rather than mechanical.

How to use the MOT trail when buying

Read the advisory pattern. A car with 5+ recurring advisories on the same components year after year was nursed by an owner who didn't fix things — those advisories will become failures on your watch.

A car with clean tests and the expected age-band wear (one set of brake advisories at year 6, one tyre advisory at year 8) tells you the previous owner was on top of things. Pay slightly more for those cars; they'll cost less in the next three years of ownership.

Frequently asked questions

The detailed FAQ below covers the most common MOT-history questions. The short version: pass rate falls with age, the items that fail change with age, and the MOT trail is the single best free source of "what does this car actually need" information.

Frequently asked questions

What's the UK MOT first-time pass rate?

Around 65% across all ages. The figure is materially higher for newer cars (90%+ at 3 years) and lower for older cars (50% range at 15+ years).

What's the most common MOT failure?

Lighting and signalling — bulbs out, dim headlights, missing reflectors. It's the easiest item to fix and the cheapest to fail; about 20% of all UK MOT fails are lighting items.

Do diesel cars fail MOT more often than petrol?

Yes, particularly post-2018 cars where the smoke-opacity test was tightened. Diesels can fail on emissions issues that don't affect petrols at all.

Are there MOT-exempt cars?

Cars over 40 years old are typically MOT-exempt unless they've been substantially modified. Owners can still choose to MOT them voluntarily.