I’m an MOT mechanic – a little-known issue could cause your car to fail… here’s how to avoid being caught out
AN MOT mechanic has revealed a little-known issue that could cause your car to fail and how to avoid being caught out.
Craig, who works at Walsalwood Tyre & Service in Walsall, West Midlands, took to TikTok to warn to watch out for a key problem.
Craig explained that you can actually fail your test because of a loud exhaust under certain circumstances.
He said: “There is actually reason for rejection in the inspection manual for ‘exhaust too noisy’.”
Exhaust systems carry waste gases out of the car after fuel is burned in the engine.
These are a mixture of carbon dioxide, carbon monoxide and nitrogen oxide as well as other pollutants.
Not only that but they also filter these gases through a catalytic converter to reduce pollution and, crucially, involve a silencer to muffle the noise of the engine.
Damage to the exhaust can cause this to fail, making the car extremely loud when it runs.
Some car owners also modify this intentionally to make their car louder.
There is, though, a legal limit to how much noise your car can make.
No car is allowed to produce more than 72 decibels, with this set to be lowered to 68 in 2026.
However, when it comes to MOTs, things are a lot less clear.
Craig added: “There is no decibel limit and decibel meter implemented as part of the MOT test.
“It is another one of those grey areas…that comes down to the tester’s discretion.
“There is a legal limit for the road but not for the MOT.”
Nonetheless, your mechanic can fail your car if they believe it to be too noisy.
According to the Center for Disease Control in the US, being exposed to noises over 70 decibels for a long period can damage your hearing, while sounds over 120 decibels can cause immediate harm.
Social media commenters were stunned by the revelation.
One wrote: “There is so much in the MOT test that is a grey area [and] just down to the tester’s opinion.”
Another added: “I failed one once before for that reason.”
It comes after a major car dealership chain announced a huge change as it sells up to a US giant.
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