How to know if your exhaust has blown

An exhaust system is one of many components checked during an MOT. As well as reducing noise and supporting vehicle performance, it also plays a crucial role in protecting the environment from harmful emissions.

But like other vehicle components, exhausts can eventually show symptoms of wear and tear. So if you’re experiencing more noise than usual or noticing plumes of smoke in your rearview mirror, here’s how to get things sorted.

Common symptoms of a blown exhaust

Our article 7 signs your vehicle has a damaged exhaust system goes into detail about symptoms of a blown exhaust. Here’s a quick overview of the main things to look out for.

• metallic vibrations and rattling
• louder than usual engine noise
• reduced vehicle performance
• hissing noises
• decreased fuel efficiency
• burning smell
• illuminated engine light

If your vehicle is showing any of these symptoms, it’s important to get your exhaust checked by a qualified technician. Not only will it help you stay safer on the road, but it can also prevent damage to other components.

What causes a blown exhaust?

There are many reasons that cause a blown exhaust. From rust and failed joint seals to a cracked manifold and worn-out gasket.

To diagnose the cause of your blown exhaust, a technician will perform a visual check to identify the issue before advising about a repair or replacement for the failing part.

Catching the issue early can prevent damage to other parts of your exhaust system – ultimately reducing repair costs and the amount of time your vehicle spends on the ramp.

Is a blown exhaust an MOT failure?

In most instances, a blown exhaust will lead to an MOT failure. This could be on the grounds of a major leak where emissions exceed regulations. Or it could also come down to failed mounting where the exhaust system becomes a danger to you and other road users.

Other instances where a blown exhaust can cause an MOT failure might be due to excessive noise or even missing components such as a Diesel Particulate Filter (DPF).

Is a blown exhaust dangerous?

A blown exhaust can be extremely dangerous. Not just for you, but also for your passengers and other road users.

One of the major risks are invisible carbon monoxide fumes making their way into your cabin which can cause headaches, dizziness and even nausea.

In other instances, a blown exhaust can also be a fire hazard with pipes and manifolds operating at high temperatures and blowing hot air onto flammable materials beneath your vehicle.

It’s also important to know driving a vehicle with a serious defect condition can lead to legal repercussions under the Road Traffic Act 1988. So never take the risk. Always get things checked out.

Can you drive with a faulty exhaust?

Although you can technically get away with minor faults, it’s not recommended. Even the smallest crack or split in a component can eventually lead to extensive repairs.

For that reason, you should be proactive about exhaust repairs or replacements. Although it comes with unbudgeted costs and time out of your day, you’ll be better off in the long run.

Why it’s important to repair a blown exhaust

Apart from reducing the risk to you and other road users, repairing a blown exhaust is important for a few main reasons:

• maintaining vehicle performance
• protecting fuel efficiency
• reducing cabin and external noise
• redirecting harmful fumes

As part of your MOT, a qualified technician will inspect your exhaust system using specialist diagnostic equipment designed to measure noise and emission levels.