What are the signs of an exhaust leak?
Signs include a louder-than-usual exhaust, a ticking or puffing noise from under the car, exhaust fumes or a smell inside the cabin, rattles from loose heat shields or brackets, and a check engine light from oxygen sensor readings. Exhaust fumes inside the car can be dangerous, so a leak should be checked promptly.
Signs of an exhaust or emission problem
- The exhaust is louder than usual or sounds like it's blowing
- You can smell exhaust fumes inside the car
- Rattling under the car, especially at idle
- Check engine light with oxygen sensor or catalytic converter codes
- A rotten-egg smell from the exhaust
- Visible smoke from the tailpipe
What does the exhaust system do?
The exhaust carries hot gases away from the engine and out from under the car, reduces noise, and — through the catalytic converter and sensors — reduces harmful emissions. Oxygen sensors also feed information back to the engine computer, which uses it to set the fuel mixture.
How do we diagnose exhaust and emission faults?
We inspect the system on the hoist for leaks, corrosion, damaged mounts and loose heat shields, and read sensor data and fault codes. Many emission problems start in the engine, so we look at misfires, fuel trims and oil consumption before condemning an expensive part.
Why exhaust fumes in the cabin matter
Exhaust gases contain carbon monoxide, which you can’t see or smell on its own. If you notice exhaust smells inside the car, drive with fresh air, and have the system checked as soon as possible.
Questions worth asking your mechanic
Whoever works on your car, these questions help you understand the job and the quote:
- Where exactly is the leak or fault?
- Is it the exhaust itself, or an engine problem showing up in the exhaust?
- Can the part be repaired, or does it need replacing?
From our workshop
Recent jobs photographed at our Sunshine North workshop.
Frequently asked questions
Why is my catalytic converter failing?
Catalytic converters are usually damaged by an engine problem — misfires, oil burning or a rich fuel mixture. Replacing the converter without fixing the cause can see the new one fail too.
Is an exhaust leak checked in a roadworthy?
Transport Victoria's roadworthiness requirements include safety-related items on the engine and body. Ask us about your specific vehicle if you're preparing for a test.