Small exhaust hole
Rust holes commonly create a blowing sound that gets worse over time.
Noise guide
Car exhaust blowing noise
If your car sounds louder than normal or makes a blowing noise from underneath, the cause is often an exhaust leak or damaged section. This guide explains common reasons and sensible next steps for UK drivers.
Common causes
Why an exhaust may make a blowing noise
Exhaust systems carry hot gases under pressure, so leaks often create hissing, blowing or roaring sounds.
Broken flexi section
The flexible joint near the engine is a common failure point.
Loose clamp or joint
Poor seals at joins can leak gases and create noise.
Damaged back box or silencer
Internal failure can make the car much louder than normal.
Broken exhaust hanger
Movement can strain joints and create leaks or knocks.
Manifold gasket leak
Leaks near the engine often sound sharper, especially when cold.
Signs that matter most
- 1Louder on acceleration
- 2Noise worse when cold
- 3Smell of exhaust fumes
- 4Rattle from underneath
- 5Recent MOT advisory for corrosion
Better next steps
1. Listen to where noise comes from
Front, middle or rear location helps identify the faulty section.
2. Do not ignore fumes
Exhaust gas leaks should be dealt with promptly.
3. Expect worsening over time
Small holes often grow larger quickly.
4. Get inspected soon
Especially before MOT testing or long journeys.
Related help
Useful linked guides
This page strengthens your noise, MOT and repair-cost topic cluster.
Most Common MOT Failure Reasons in the UK
Useful if your MOT is due soon.
Read guide →How to Prepare for MOT Test UK
Helpful before a test or retest.
Read guide →Car Repair Costs Guide UK
Useful if repair quotes are needed.
Read guide →Engine Misfire Symptoms and Causes
Helpful if noise is joined by poor running.
Read guide →Car Smells Like Burning Rubber
Useful for other smell/noise issues.
Read guide →Diagnostics Hub
Browse more noise and fault guides.
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