A gas smell in your car can be caused by a leaking fuel line, a loose gas cap, or a faulty injector. Have it checked right away because it is a fire risk.
Common causes
- Loose or damaged gas cap.
- Fuel line leak.
- Leaking injector.
- Cracked EVAP canister.
- Faulty fuel tank.
Safety
Gasoline vapor is flammable. Don’t smoke. Park outside.
What to do
- Tighten the gas cap.
- Check for fuel drips.
- Don’t drive if the smell is strong.
- See a mechanic right away.
Health
Fumes cause headaches and nausea.
Fuel system causes
- Loose, damaged or missing gas cap, which lets fuel vapors escape and may trigger a check engine light.
- Leaking fuel line, fuel injector, fuel pump or fuel tank.
- Faulty evaporative emissions system (EVAP), including the charcoal canister.
- Overfilling the tank.
- Spilled fuel in the trunk or from a gas can.
Engine causes
A rich fuel mixture from a faulty sensor produces a strong gas smell in the exhaust. Unburned fuel from a misfire can also smell like gas.
Exhaust leaks
A leak before the catalytic converter lets fumes enter the cabin through the vents. Exhaust contains carbon monoxide, which is odorless and deadly.
Safety
A strong gasoline smell is a fire hazard. Fuel vapors can ignite from sparks or hot surfaces. If you see fuel dripping or smell strong fumes:
- Stop driving in a safe place and turn off the engine.
- Do not smoke or use flames.
- Get out of the car and keep away from the vehicle.
- Call roadside assistance or a mechanic, and have the car towed.
What to check
Make sure the gas cap clicks tight, look for drips under the car and see if the check engine light is on.
Health effects
Breathing gasoline vapors can cause headaches, dizziness, nausea and, at high levels, loss of consciousness. Carbon monoxide poisoning symptoms include headache, weakness, dizziness, confusion and nausea. Open windows and get fresh air, and call 911 if symptoms are severe.
Repair costs
A new gas cap costs 15 to 30 dollars. Fuel line repair can cost 150 to 1,000 dollars. A fuel pump replacement costs 400 to 1,200 dollars or more.
Do not ignore
Persistent gas smell needs professional inspection.
Quick safety steps
Fuel odor inside a cabin can mean a fuel leak, which is a fire risk. Stop driving if the smell is strong, turn off the engine, avoid sparks and open flames and get the car inspected. Common causes include a loose or damaged gas cap, leaking fuel injector seals, a cracked fuel line, a failing charcoal canister in the EVAP system or a rich running engine. A check engine light with code P0440 to P0457 often points to EVAP system faults.
Cost and health notes
Replacing a gas cap costs roughly 15 to 30 USD, while fuel line or tank repairs can run hundreds to over a thousand dollars. Gasoline vapors contain benzene, a known carcinogen, and inhaling them can cause headaches and dizziness. Never ignore a smell that is accompanied by fuel dripping under the car.
Based on data from the US Environmental Protection Agency and the National Highway Traffic Safety Administration
