What to Do if Your Car Smells Like Gas

Stephen Fogel
February 8, 2018

car smells like gas

Have you noticed the pungent odor of gasoline inside your vehicle? A fuel smell can occur for several different reasons. Some are minor issues and nothing to worry about. Others can signify a fire hazard — a very dangerous situation. 

IMPORTANT: If you have any reason to believe that your car has a gasoline leak, don’t drive it. Call your mechanic immediately for advice. If it’s a significant leak, with a noticeable amount of gas coming out of your vehicle, call the fire department without delay. Better safe than sorry!

Let’s go through the reasons why you might smell gas and sort things out.

At the gas station

Gasoline vaporizes quickly, making it an excellent fuel source for your car. It’s also got a noticeable odor, and because it vaporizes so easily, some of its vapors will inevitably escape during refueling. That distinctive smell can remain in your vehicle after you leave the gas station.  

If the smell goes away shortly after your fill-up, it was probably just some free-floating fumes that drifted into your car through an open window or door. Driving a short distance with the windows down should get rid of the odor. 

If the gas smell does not go away quickly, the issue may be that you got some gasoline on your hands or clothes while filling up, or you stepped in some spilled gas near your vehicle. When you get home, wash your hands and change your clothes and shoes, then see if the gas smell is still in your car.

It could also be that you overfilled the tank and spilled a little gasoline on the body of the car near the filler. Or maybe you forgot to tighten the gas cap. Make sure the cap is on and is tight and then rinse that part of the car’s exterior with clean water. 

You may also have a gas smell from the expansion of fuel in the tank after you filled it up. This will be more of an issue in older cars that don’t have the sophisticated vapor capture systems required in modern vehicles.

More dangerous causes 

If your fuel system is the culprit, you’ve got a more dangerous situation on your hands. Having pressurized gasoline leaking from your car isn’t an issue you can put off. You must have your mechanic repair it immediately — you’re at risk of having your car catch fire. 

Fuel injector leaks

Your fuel injectors spray pressurized fuel either into the intake manifold or directly into the cylinders. The injectors use rubber seals to protect against fuel leaks. Wear and tear can cause these seals to deteriorate, producing a leak. The injectors can also leak if they are old and worn. If this is the cause, you’ll notice a very obvious gas smell.

Your mechanic should check both the injectors and the seals. You may simply need replacement seals. Or, you may need to replace the fuel injectors as well, which will cost more.

Note: Cars with carburetors — typically those made before the 1990s — will normally give off a gas smell at times. This is due to the way carburetors are designed, with a float bowl that houses some residual fuel after you shut the car off. This fuel then vaporizes and produces a gas smell that should dissipate after a while.

Fuel line leaks

Your fuel lines and hoses carry pressurized gasoline from your fuel tank to your engine, where it’s burned to produce power. On most cars, these are a combination of metal lines and rubber hoses. They connect to your fuel filter and fuel injectors (or carburetors in older vehicles). A leak can occur as a result of age, wear, corrosion or damage to the hoses and lines. You will probably notice a gas smell if this happens.

Fuel-injected engines require high fuel pressures, so a leak may occur as either a drip or a fine atomized spray. This will produce a strong gasoline odor, and is very dangerous if it gets near hot exhaust or engine parts.

If you notice or suspect a fuel line leak, have it repaired immediately. Replacing the bad hoses or lines should solve the problem.  

Get it diagnosed by a professional

Fuel tank leaks

Your fuel tank is a common source of fuel leaks. Cars made before the mid-1980s tend to have metal fuel tanks, which can rust out, rupture or get punctured by road debris. Vehicles made since then usually have plastic tanks, which can also develop cracks or have leaks from their evaporative fittings or access covers for internal components. 

You may notice a fuel stain on the ground under your vehicle where you park it. There may also be a stain on the underside of the tank, at the site of the leak. Some metal tanks can rot on the top, where you can’t see. A gas smell can be carried into the car from the leaking fuel.

If your plastic tank is cracked, or you have a metal tank, you’ll probably need a replacement. Seals and hose fittings can be replaced more easily. Either way, this is definitely a job for your mechanic.

Engine running too rich

When an engine is “running rich,” that means it’s using more fuel than is needed for proper operation. This is more of an issue with older vehicles that use carburetors, which can be manually adjusted to run this way. 

Fuel-injected engines are computer-controlled, and are programmed to adjust their fuel-air mixture to be optimal for the conditions. If your fuel-injected car is running too rich, you may have an engine computer problem. It could also be an issue with the fuel pressure regulator.

The excess fuel running through your engine can produce a gas smell from the exhaust that can be noticed inside your car. It can also make your oil smell like gas, which is very bad. This means that your oil is being diluted and not protecting your engine the way it should. Having your mechanic diagnose and repair the issue should resolve the problem. 

Other sources

Gas cap 

We touched on it briefly earlier, but you might want to check your gas cap, as well. You may not have closed it tightly enough, or you might even have left it behind at the gas station. If you have an older vehicle, the fuel cap can wear and deteriorate; it may no longer be able to seal well enough. 

The lack of a properly secured gas cap can turn on your check engine light and even cause your car to go into “limp-home” mode, where only one or two lower gears will be available. If this is the source of your gas smell problem, it’s easy and inexpensive to replace the cap.

Evaporative system 

Vehicles made in the past 30 years or so have evaporative emissions control systems, which use a charcoal-filled canister to capture gasoline vapors inside the tank. The canister stores the vapors, which are periodically sent to the engine to be burned along with the fuel in the cylinders. This system prevents the vapors from escaping into the atmosphere, where they can react with sunlight to produce smog. 

A faulty charcoal canister will often produce a gas smell inside the vehicle. The canister may have a leak or a crack in it, or its lines may be bad. This is not easy to check visually, but since the canister is part of your emissions control system, it’ll likely turn on your check engine light. 

The system also has several valves, hoses and a pump that could leak. If any of these go bad, they could cause the check engine line to come on, even before a fuel smell is discernible.

Take your car to a repair shop, which can use an OBD code reader and other diagnostic equipment to identify the source of the problem and then fix it. You may need a replacement canister or other new parts.

Fuel filter

Your fuel filter removes impurities and other particles from your gasoline before it enters the engine to be burned. A damaged or clogged fuel filter may leak, either from its body or at the fittings on each end of the filter. A replacement filter will usually solve this problem. You may want to let your mechanic handle this one, as he or she will have the special tools needed to work with the fittings.

Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.