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- Vehicle Symptoms
- What Are Common Car Failure Searches?
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- Why Does My Car Drive Weird?
- Why Does My Car Make Noises?
- Why Does my Car smell?
- Symptoms Without Summary
- Car Leaking Coolant
- AC Isn't Cooling
- AC Blowing Hot Air
- Shaking While Driving
- Overheating AC
- AC Smells Like Vinegar
- Heater Not Working
- Windshield Wipers Don't Work
- Car Leaking Water
- Car Leaking Red Fluid
- Car Battery Leaking
- AC Only Work Sometimes
- Shaking While Idle
- Shaking At High Speeds
- Evap System Leak
- Shaking While Braking At High Speeds
- Shaking When Stopped
- Shaking When Accelerating
- Radiator Leaking
- Pink Fluid Leaking
- Car Leaking Oil
- AC Not Working.
- Car Leaking Gas
- Power Steering Fluid Leak
- Bad Brake Caliper
Hey, Why is My Car Leaking Gas?
If you are short on time and want to fast-track the process to professional help, click Yes
Is Your Car Leaking Gas?
The gas leak is commonly caused by a crack or looseness in the fuel tank. However, it can also be caused by a misplaced gas cap, faulty fuel injectors, damaged fuel lines, valve leaks, or even a broken sensor allowing fuel leaks.
Gas powers our vehicles because of its flammability. So, when it leaks, it reasonably causes concerns. But, in addition to the fire hazard, gas vapors are toxic and harmful to the environment.
A vehicle's "check engine light" may indicate a fuel leak, and the "gas cap light" ensures your fuel system is sealed. Remember, this pressurized, sealed part is designed to safely contain fuel and harmful vapors.
Gas leaks are easy to detect since they strongly smell and leave puddles under your vehicle. But, sadly, gas leaks don't only put the driver in danger but everyone around the car as well.
Let's Get To The Bottom Of It!
- You may also smell gas fumes while parked or see a puddle of clear fluid under your car that chan...read more
You may also smell gas fumes while parked or see a puddle of clear fluid under your car that changes colors on the surface.
The fuel line on a modern vehicle is a rigid, high-pressure plastic with quick-disconnect fittings that are formed on both ends. It's designed to carry the fuel from the gas tank to the injector rail. If the plastic line develops a crack or the rubber seals in the quick disconnects degrade, the line will start leaking as the fuel pump runs. Since the pump is idle, you'll notice gasoline puddling underneath the vehicle.
- You might also smell gas fumes while driving or notice decreased fuel economy. Fuel tanks ...read more
You might also smell gas fumes while driving or notice decreased fuel economy.
Fuel tanks are designed to reduce pollution by sealing fuel and vapors inside. But unfortunately, many modern vehicles have flexible plastic tanks that can weather, developing cracks in the seams. If this happens, a fuel puddle can build up under the car wherever it's parked.
- You might also notice that the engine is difficult to start or the motor oil seems thin. T...read more
You might also notice that the engine is difficult to start or the motor oil seems thin.
The fuel injectors are triggered electronically to open and spray atomized fuel into the intake. Some O-rings seal the injector to the intake and the fuel rail. These O-rings are rubber and can become brittle and crack over time. These seals start to leak during engine operation. Air pushed through the vehicle by the engine makes the gas smell more noticeable while driving.
- You may smell gas when opening the hood or have trouble starting the engine after fueling up....read more
You may smell gas when opening the hood or have trouble starting the engine after fueling up.
The gas cap is sealed to the filter neck with an O-ring to prevent the escape of harmful vapors. However, these seals are rubber, which can rigidify and crack over time. When these cracks develop, the evaporative emission system cannot form a vacuum to hold pressure in the fuel system. This failure turns the gas cap light on.
- You might also see a puddle of gasoline under the vehicle or smell gas fumes while driving. <...read more
You might also see a puddle of gasoline under the vehicle or smell gas fumes while driving.
The fuel pressure sensor on top of the fuel pump module detects pressure in the fuel tank to verify that no fuel vapor leaks into the atmosphere. If you lose pressure because of a seal leak, the "check engine light" will come on.
- The engine might also be hard to start at other times, and you might smell gas when opening the h...read more
The engine might also be hard to start at other times, and you might smell gas when opening the hood.
The purge control valve is designed to stay closed, only occasionally opening to evacuate gas fumes accumulated in the charcoal canister. This helps to dry out the canister. However, if this valve fails and sticks open, adding fuel to the tank forces gas fumes into the intake, flooding the engine. You will experience this issue by struggling to start your car after getting gas.
Find Professional Help
Please select your vehicle's brand and location so we can locate the best professional help for youVehicle Health Inspection Proof
Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.
Fuel tank leaking
Fuel line leaking
Fuel injector leaking
Gas cap leaking
Fuel pressure sensor leaking
Purge control valve leaking
The proof image shows gas dripping off of the leaking fuel tank.
A customer dropped off their vehicle after noticing a puddle of clear liquid underneath it in their garage. They also reported a powerful smell of gas. They checked the gas cap and ensured it was tight before bringing the car in.
The technician did not notice anything about the customer's concerns on the test drive.
During the vehicle health inspection, the technician lifted the vehicle and saw that its gas tank was wet and smelled like fuel; these elements could indicate a fuel leak. To further investigate the issue, the customer authorized the shop to perform additional tests to confirm a fuel leak suspicion.
The mechanic pressurized the fuel system with a smoke machine and dropped the gas tank low enough to check the top for leaks. They found the leak and verified that it was coming from the seam on the side. Unfortunately, the gas tank will need to be replaced.
1/6
The proof image shows a leaking fuel line at the seam on the fuel pump.
A customer dropped off their vehicle after noticing something odd. First, the car left a smell of gas in the garage the night before. Then, the following day, the gas smell was gone, but when they started the car and left it idling to warm up in the garage, a puddle of gas formed underneath the vehicle.So they shut the car off and had it towed.
Once it arrived, the technician started the vehicle and drove it directly into the service bay. During the vehicle health inspection, the technician noticed gas dripping off the gas tank while the car was running. To further investigate the issue, the customer approved additional tests.
The mechanic lowered the gas tank enough to see the top of the tank. Then, they asked for an assistant to get in the vehicle and cycle the key off and on while they inspected the fuel system.
The technician verifies gas leaks from the fuel line attached to the pump. The fuel lines' assembly will need to be replaced.
2/6
The proof image shows a spot of the gas leak between the rail and the injector.
A customer dropped off their vehicle concerned about smelling gas while driving. They reported they did not see any gas puddling underneath the car after parking or running it. However, they smelled gas when they warmed the vehicle in the garage.
On the test drive, the technician verified a gas smell while driving.
During the vehicle health inspection, the shop noticed that the number one fuel injector was wet.
The mechanic started the car and dried the injector with compressed air to verify where the leak was coming from. They confirmed that the leak came from the seal between the injector and the injector rail.
The shop recommended replacing all injector seals to prevent more leaking since they are all the same age.
3/6
The proof image shows the cracks in the gas cap seal that allow gas vapors to escape.
A customer dropped off their vehicle because the "gas cap light" turned on and off. They reported repeatedly tightening the gas cap and screwing it on with a ratchet. Even after tightening, the "gas cap light" kept flashing.
On the test drive, the technician verified that the "gas cap light" was on the dashboard.
During the vehicle health inspection, the mechanic noted that the gas cap had cracks in the O-ring seal. The technician did a vehicle code scan and found an evaporative emission system leak. To further investigate the issue, the customer approved additional tests.
The mechanic performed a smoke test on the evaporative system and found no leaks. The gas cap is the only part related to the issue and needs replacement.
4/6
The proof image shows fuel leaking from the car's fuel tank pressure sensor seal.
A customer dropped off their vehicle after driving with the "check engine light" on for about a month. Note that the "check engine light" must be turned off for the vehicle to pass an emissions check.
The technician performed a test drive and noted the "check engine light" on the dashboard.
During the vehicle health inspection, the shop noticed nothing related to the customer's concerns. Then, they ran a vehicle code scan and found an evaporative emissions control system pressure sensor range/performance problem. To further investigate the issue, the customer approved additional tests.
The technician performed a smoke test on the evaporative emission system. They detected smoke coming from the top of the gas tank. Further testing was authorized, and they removed the entire gas tank.
After pressurizing the gas tank, the technician noticed a leak on the tank's fuel pressure sensor. They removed the pressure sensor and found that gas had intruded into the sensor and caused it to fail. The shop recommended replacing the fuel pressure sensor and seal.
5/6
The proof image shows where to apply the vacuum to test if it holds when attempting to verify that the purge control valve has failed.
A customer dropped off their vehicle after it had trouble starting. They noticed that starting it with a full fuel tank is always troubling.
The technician did not notice anything about the customer's concerns on the test drive. Then, however, they saw the "check engine light" on the dashboard.
During the vehicle health inspection, the technician found nothing related to the problem. Then, the mechanic did a vehicle code scan and detected an evaporative emissions system leak. To further investigate the issue, the customer approved additional tests.
The technician performed a smoke test on the evaporative emission system and found that the system wasn't holding pressure. They didn't notice any smoke from the lines or the tank.
The mechanic removed the purge control solenoid and tested it with a vacuum pump. Unfortunately, the tests proved that the valve was stuck open. Therefore, the purge control valve needs to be replaced.
6/6Typical Fixes to Address the Cause(s)
The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.
The AutoTechIQ ranking for Safety, Cost Avoidance, and Environmental Impact is
Vehicle Symptoms
Below are just a few examples of typical Symptoms and Fixes your car might be experiencing
Other things your auto repair shop might talk about:
Gas leak in car. Gas tank vent hose. Car gas leaks. Gas tank caps.