Smoke and smells
Exhaust fumes smell inside the car: why it is dangerous
Smelling exhaust fumes inside the car means gases are getting in through an exhaust leak, a seal or a gap in the body. It is dangerous because carbon monoxide can come in with them, and it has no smell but causes dizziness, headaches and drowsiness.
Stop as soon as it is safeSmoke and smells
Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Do not keep driving. Open the windows, stop as soon as it is safe and do not carry on if you feel dizzy, get a headache or feel sleepy. Do not drive with the smell inside the car until the exhaust has been checked. If anyone feels unwell, get out into fresh air and seek medical help.
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
- Exhaust leak: a rusted pipe, gasket or muffler, especially under the cabin.
- Exhaust manifold gasket: usually also makes a puffing noise when cold.
- Body seals or grommets: on the tailgate or the floor, letting in the gases that swirl behind the car.
- Following the vehicle ahead closely with the vents open: not a fault, but noticeable in traffic jams and tunnels.
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
Air out the car and notice whether the smell only appears with the tailgate or the windows open.
With the engine cold, look under the car for broken or hanging pipes or soot around a joint.
Listen at a cold start for the exhaust puffing or sounding louder than normal.
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, which are thrown off if air gets in through a leak ahead of the sensor.
Frequently asked questions
How do I know if it is carbon monoxide?
You cannot smell it. If you smell exhaust and also feel dizzy or have a headache, act as if it were there: fresh air and stop driving.
Does an exhaust leak set a trouble code?
If it is ahead of the O2 sensor, it can set lean or sensor codes. Many leaks set none.
Will the car pass inspection with an exhaust leak?
Usually not: leaks and excessive exhaust noise are defects at the inspection.
Keep reading
- Exhaust and emissions: how they work and what fails
- Exhaust louder than normal: what it means
- Burning smell in the car: what it could be and what to do
- Smell of gasoline or diesel in the car: 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