Car Repair and Maintenance

Car Smells Like Gas Inside [Causes and Fixes]

If your car smells like gas inside, it could be a leak in the fuel system, EVAP system issues, loose, missing, or faulty gas cap. Whatever the cause, the smell is unpleasant and needs attention to improve your driving experience. In some circumstances, gasoline and its fumes have caused serious fire hazards, so you don’t want your vehicle interior smelling like gas.

Reasons car smells like gas inside and how to fix

car smells like gas inside

While some of the issues are fixable by non-professionals, others may require professional intervention. As you go through and examine the possible causes below, make sure to see your mechanic where necessary.

  1. HVAC system problem

If your spark plugs are not properly tightened, they may have come loose over time. In this case, the fumes will exit the combustion chamber and enter the air intake for the car’s HVAC system, causing the engine to emit exhaust directly into the air vents.

On the threaded portion of your spark plugs will be washers that seal everything. If these washers are damaged, missing, or cracked, then the gas smell may emanate from there.

How to fix

Check if the spark plugs are in good condition. If so, remove each one carefully and remember where they belong. If you re-install them incorrectly, your car will not start. It could be simpler to remove and replace each item individually.

Otherwise, examine the torque. Loosen the spark plugs until you tighten them well enough. Screw it in as tightly as possible with your hand. Use the wrench and crank it clockwise by a quarter turn. Now you should have the appropriate torque. Repeat the procedure for other spark plugs. This will ensure that all of your spark plugs are properly torqued.

  1. Bad O-ring or gasket surrounding the oil cap

This may be one of the most typical causes of a car’s gas smell. It takes less than a minute to fix this, and you don’t even need to jack up your car.  The oil cap is the cap for the oil reservoir. This is the component removed during an oil change. If it is not properly seated, oil and gas vapors will escape into the atmosphere, causing your car to smell like gas inside.

How to fix

Find the oil cap after raising the hood. Typically, it is black and has the word “Oil” or an image of an old-fashioned oil can. Examine the rim of the cap. Are there several spots of dirt and grease beneath the cap? This is a clear indication that the cap is not properly sealed.

Remove the cap and examine the O-ring on its underside. If it is deformed, broken, or missing, get a replacement.

The final step is to examine the cap itself. If the cap is broken or fractured, simply replace the entire piece. Make sure you find a new cap of the correct size (they make a lot of different sizes depending on your car). If everything else fails, search the junkyard to see if you can find an oil cap.

  1. An oil leak

The oil in your car is combined with unburned gasoline. This suggests that an oil leak could also make your car smell like gas inside. In this case, the gas must be burned on a heated surface for the smell to be produced.

How to fix

Open the hood of your car. Utilize a flashlight and examine your surroundings closely. If you observe any black, moist, or greasy areas on the engine, they may be oil.

You can also detect an oil leak by inspecting the undercarriage of your car after it has been parked overnight. If you observe a dark area underneath, it may be oil.

The valve cover gaskets are one of the most likely locations for oil to leak. These are located directly above the exhaust manifold at the top of the engine. This part of your car generates a great deal of heat, so if oil were to spill here, you would surely smell gas.

You can also view beneath the hood when the engine is running. If the engine is emitting smoke, this is a strong indication of an oil leak.

The solution is dependent on the source of the leak. You may need to replace a component, a gasket, an O-ring, or tighten an object. If you cannot locate the source of the leak, you will have to service your car.

  1. Exhaust fumes

Your car’s exhaust fumes are another component that contains gasoline. These vapors are the result of burning gasoline to accelerate your car, and they are intended to be expelled by the exhaust pipe.

If your car has an exhaust leak before the catalytic converter, you will detect a gas smell. The catalytic converter washes the exhaust and eliminates smell, so if you smell something, it must have occurred before the catalytic converter.

How to fix

It is difficult to fix this specific issue yourself because it is quite technical, but if you have a good sense of your car’s sound, you will notice a stronger exhaust noise if there is an exhaust leak. By revving your engine, you will be able to hear the difference more clearly.

A leaking exhaust will also produce a tapping sound when the car accelerates. The ticking noise grows louder as the distance between the leak and the engine increases. Toweling over the tailpipe is an alternative method for resolving this issue. Hold the towel so that it blocks the tailpipe’s outlet. As the car idles, see if the towel becomes compressed. If not, then a leak exists somewhere.

This is an issue that cannot be resolved on your own. A leaking tailpipe must be taken to a professional mechanic, but at least you now understand why your car smells like gas inside!

  1. Missing, loose, or defective gas cap

Similar to a missing or loose oil cap, a gas cap can generate a gas smell. The most notable difference is that your car will not smell like gas inside. You will mostly smell gas if you are outside of your car or if you have the windows down while the engine is running.

How to fix

The first thing you need to check is whether or not the gas cap is in place. You may have forgotten to put it back on after filling it up.  If there is a cap, turn it clockwise to ensure that it is secure. If it is already fully tightened, remove it and examine it. Replace the gas cap if the O-ring is flat, broken, missing, or cracked.

  1. Exterior gas spill

You may have spilled gasoline on your car’s exterior. This does not indicate a gas leak, but rather that gas was recently splattered on your car.

How to fix

If you’ve checked everything else and are still unable to identify the issue, you should try to recall the past. Have you lately filled up your petrol tank? If so, roll down the windows and drive for a while.

If the spill happens in your car, use a towel to absorb as much gas as possible. Apply a mixture of baking soda, hot water, and white vinegar in equal portions to the affected areas.

  1. You own an old car

Due to the technology employed in the carburetor and float bowl, cars manufactured before the mid-1980s can emit a gas smell when started and switched off. In addition, these older cars often lack a powerful evaporative emissions system.

How to fix

In this instance, neither you nor a mechanic can find a solution to this issue. As long as the faint gas smell disappears after a few minutes, there is no need for concern.

  1. Poor fuel pressure

The fuel system of your car is frequently under pressure. This helps your car reach its destination and keeps it driving smoothly. If your car has inadequate fuel pressure, you will detect the smell of excess gas burning. Your car’s gas mixture will be either too lean or too rich if the pressure regulator is malfunctioning.

How to fix

Regardless, this is a problem that your professional mechanic can fix.

  1. A gas leakage

If your car has a gas leak, you will perceive a gas smell. Your car pumps gas from one end to the other.

The first sign of a gas leak is a fuel gauge that drops significantly more quickly. If your fuel level decreases overnight, this is a definite indication of a gas leak.

You can also let your car idle for a short time and look for a rainbow puddle underneath. Checking your car after it has sat overnight should also reveal a puddle if there is a gas leak.

The source of the leak could be the injector, fuel tank, fuel line, or injection line. One technique to distinguish between a fuel leak and a gas leak is by smelling the mixture coming out. The smell of gas will be fainter in oil spills than in gas leaks.

How to fix

Take your car to the mechanic and inform them that it has a gas leak.

  1. Defective charcoal canister

A defective charcoal canister could also be the reason your car smells like gas inside. This is a component of your car’s evaporative emissions control system loaded with charcoal, and stores fuel vapors before they are transferred to the engine to be burned.

A damaged canister allows fuel vapors to go out, and you will likely be able to smell them from within your vehicle. In some cases, your check engine light will come on.

If you hear a pinging sound, experience decreased performance, or smell higher emissions than usual, this may indicate a problem with the charcoal canister.

How to fix

The replacement is complex, so you should take your car to a professional mechanic.

Is it safe to drive a car that smells like gas?

It’s not safe to drive a car smelling like gas. The combustion of gasoline fumes produces carbon monoxide and methane. A modest smell of gasoline may just cause you headaches, but prolonged exposure could lead to major health issues. Per the State of Illinois, other problems include nose and throat irritation, headaches, dizziness, nausea, vomiting, confusion, and breathing difficulties.

Fume exposure and unsecured gas caps are harmless and will not cause any issues if you drive a car with a gas smell. As soon as the problem is resolved, the smell will rapidly go. However, prolonged exposure to gasoline fumes poses a health risk and can be lethal.

If your car smells like gas due to a fuel leak, you should not drive. Depending on the degree of the fuel system damage and leak, you should have your car towed to the shop. Immediately stop the leak and restore any damage to the car. The repair and/or replacement costs will vary; repairing a minor hole and rebuilding the fuel tank cannot cost the same amount. Driving with a leaking gasoline system could exacerbate the issue.

Prevention is preferable to treatment; have your car serviced every 10,000 to 12,000 miles. In addition to inspecting the gas cap when changing the oil every 5000 – 7000 miles, you may also wish to inspect the oil filter. Examine the rubber gasket or O-ring for evidence of wear, in particular.

How to prevent gas smell in cars

Even brand-new cars require routine maintenance to prevent the majority of the aforementioned causes. If you service your car every 12,000 miles, you will discover any problems before they become costly.

In addition, the following tips are helpful to prevent your car from smelling gas.

  • Secure your gas cap properly after filling it up at the gas station.
  • Check the condition of the gas cap when performing maintenance on your car. Replace your gas cap if it shows indications of wear.
  • Follow the instructions in the owner’s manual while adjusting the spark plugs.
  • Inspect the oil cap gasket or O-ring and replace it if necessary, preferably every 5,000 to 7,000 miles.


Now you know what to look for if your car smells like gas inside. This is a potentially dangerous scenario, so do not delay taking action.

Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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