The smell of gas in or around your car may be an inconvenience, something completely harmless or a severe hazard. When you smell gas, attempt to locate its source in order to determine the cause. If you can’t find the source by sight or smell, take additional steps to discover symptoms that will help you diagnose and repair the cause of the smell.
Exposure to Gas Vapors and Spills
If you park at a gas station, fumes from the pumps can enter your car when you open the doors or windows. Spilled gas in or near the car can also cause a notable odor in the air within your car. If you suspect that the gas smell in your car is due to such an external source, keep track of how long it takes to fade. If the smell does not fade, you may have a more serious problem.
Gas Smells in Older Cars
According to Popular Mechanics, cars made in the early 1980s or earlier will normally emit a slight gas odor after shut off. This is due to fuel afterboil in the carburetor float bowl. Newer cars should not produce this smell after shut off as they are equipped with evaporative-emissions systems designed to prevent this.
A gas leak can occur at many points along your fuel system. A leaking fuel line can be discovered by looking for gas puddles under your car when parked. A fuel-injection line may also leak, causing you to notice the smell of gas fumes during and immediately after driving. A fuel-tank vent hose may also leak, causing unburned gas to exit your fuel system as vapor. Leaks should be repaired as soon as possible, as a gas puddle under or near your car is a fire hazard.
Irregular Fuel Pressure
A bad fuel pressure regulator can cause your car to burn too rich or too thin a fuel mixture. When you burn excess gas, this can increase the presence of gas fumes in your exhaust. Anyone outside of the car will notice the smell of gas vapors while it runs. If exhaust enters your ventilation system through a leak, the interior may also begin to smell like gas fumes. Other signs of a failing fuel pressure regulator include decreased power and lower than normal fuel efficiency of your car.