Can you tell if a car is going to FAIL the MOT just by looking at it?
The short answer? Yes!
The MOT test has some pretty rigorous checks – like the emissions test for example – but so
many failures are caused by obvious, visible problems. Experienced mechanics, car traders,
and even observant owners can often spot an MOT fail from meters away, just by looking at
the car.
From bald tyres to broken lights, here’s how we could spot an MOT fail with nothing more
than a glance.
Tyres – the instant fail
Tyres account for 10% of all MOT failures (DVSA), and most issues are glaringly obvious.
We can spot a breaker of the 1.6mm rule pretty easily now, and if the tread looks visibly low,
it likely is. The "20p test" (inserting a coin into grooves) works, but any tread below 2mm is
risky; worn tyres often fail on other defects too.
Saw-toothed tyre edges, uneven or bald patches suggest suspension or alignment faults…
and that’s another test fail. Bulges and cracks in tyres can mean instant rejection, too. Even
a small bulge indicates structural failure inside the tyre, which could become a high-speed
blowout! Mismatched tyres on the same axle can also trigger an MOT failure.
Vehicle Lights
Faulty lights cause 30% of MOT fails, and nearly all are visible
Non-working headlights, brake lights, or indicators are relatively easy to spot (have someone
check your brakes while you look) – and cheap to fix. Cracked or missing housings are even
easier to spot – and exposed bulbs (especially on headlights) usually mean your car will fail.
Bodywork: rust, breakage, and structural damage
Corrosion can cause an MOT fail – but testers look for specific problems.
Rust in critical areas of a vehicle will mean it fails the MOT test. Significant rust and
corrosion found within 30cm of safety components (like seat belt anchors, braking systems,
or steering mechanisms) can mean an automatic fail. More obvious from the outside, holes
in critical panels (especially floors or sills) often indicate structural weakness.
Protruding trim or broken plastic can fail for being "injurious to pedestrians" – and a
damaged windscreen can be problematic, too. Cracks in the driver's sightline (larger than
10mm) will cause an MOT fail, and chips directly in front of the driver (larger than 40mm)
also fail.
Saggy suspension
Proper suspension tests require a ramp – but sometimes, you know the suspension is
cooked just by looking… For example, if one corner of the car sits lower, that suggests a
linkage failure of some sort, and will fail the MOT.
Your exhaust is exhausted
A smoking, noisy exhaust often signals an imminent MOT fail. Blue smoke usually means
burning oil, and engine issues. Black smoke usually means a failed emissions test is on the
cards, especially for diesels.
Leaks
Puddles under the car aren’t a good sign… Oil leaks can cause a failure if they’re significant,
and are impacting key safety features like braking. Brake fluid leaks are another instant fail,
and a quick check around the wheels and master cylinder can reveal this as a problem.
Park on a big sheet of paper, and you’ll be able to spot any slow, enduring leaks easily after
a few minutes.
The 2-Minute MOT checklist
Before booking a test, just look at your car – you won’t need any special tools!
✅ Tyres – are they balding, cracked, or bulging?
✅ Lights – are they ALL working? Are any housings broken?
✅ Bodywork – can you see any rust, holes, or sharp edges?
✅ Suspension – is your car sitting level? Does it bounce a lot?
✅ Exhaust – can you see any smoke coming out, or holes?
✅ Leaks – is anything leaking out of the car?
✅ Are any dashboard warning lights on?
If you answer yes to any of these, then you should expect to fail the MOT…
Book your MOT now
Book your MOT test in Boyatt Wood today, with We Only Do MOTs. We promise to provide
an impartial, independent MOT to everyone – and will carry out most minor repairs for free.
Send your message to enquiries@onlydomots.co.uk or call us on 023 8064 7180
