Noises
Exhaust louder than normal: what it means
If the car sounds louder, raspy or makes a rhythmic puffing sound, especially at a cold start or when accelerating, the exhaust has a leak: a gasket, a rusted pipe or a broken muffler. Besides the noise, the gases can get into the cabin.
See a garage soonNoises
Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Carefully, and only as far as the garage. See a shop soon. If you smell fumes inside the car, feel dizzy or get a headache, air out the car, stop and do not carry on. If a part is hanging or scraping the ground, do not drive until it is secured.
A careful, general answer: only someone who inspects the car can say whether it is safe to drive. When in doubt, stop somewhere safe and call for assistance.
Most likely causes
- Rusted muffler or pipe: the most common with age, especially with short trips.
- Manifold or joint gasket: a rhythmic puffing that is more noticeable when cold.
- Broken hanger or rubber mount: the exhaust hangs and knocks against the underbody.
- Exhaust flex pipe: the mesh breaks and rattles when accelerating.
Listed from more to less common in general; on your car they may be different. A fault-code reading and a check at the garage confirm which one it is.
To understand it better: What is an oxygen sensor and when does it fail? What is a catalytic converter and why does it fail?
Car system: Exhaust and emissions
What you can check yourself
With the engine cold, look under the car for a hanging exhaust, holes or soot at a joint.
Listen at a cold start for where the puffing comes from.
Notice whether you smell fumes inside the car.
Safe checks only: with the engine off and cold whenever you look under the hood, without taking anything apart and without touching hot or moving parts.
How the ECO-LITE helps diagnose it
Plugged into the OBD socket, the ECO-LITE reads the fault codes of the control units that answer, with the freeze-frame data captured when the fault happened, and shows live data on your phone or computer. With your permission, your garage can see them remotely before you bring the car in.
What to look at here: O2 sensors and fuel trims: a leak ahead of the sensor can skew the oxygen reading.
Frequently asked questions
Will a loud exhaust pass inspection?
Usually not: excessive noise and leaks are defects at the inspection.
Can it set a trouble code?
If the leak is ahead of the O2 sensor, mixture or sensor codes can appear.
Can the exhaust be welded?
Sometimes, but if the pipe is badly rusted it does not last long. The shop will tell you what is worth it.
Keep reading
- Exhaust and emissions: how they work and what fails
- Exhaust fumes smell inside the car: why it is dangerous
- Rotten egg smell from the car: what it means
- Clunking noise over bumps: causes and what to do
- Car symptoms: what they mean and what to do
- Check engine light on: what to do
- How to read and clear your car's fault codes
- OBD fault codes: what each one means