Should a Gas Tank Hiss When Opened?
The world trained us to notice the sounds around us. One of the sounds that used to make me concerned was when I would open my gas tank and some hissing would come out of the tank. Is there a problem? I would ask. One would think the gas tank was going to explode.
The hissing sound from a gas tank is normal, as long as it only occurs when you open the tank. It should not continue hissing when the tank is open or after you close it. Hissing when you remove the gas cap is caused by the buildup of pressure in the gas tank. It is a sign that the gas tank is releasing this pressure. If the hissing continues, you should take action because it can be a sign of danger.
Let us look at the cause of the pressure release from the gas tank and the hissing sounds from the gas that you need to worry about.
Contents
Why Does My Car Gas Tank Hiss When I Open It
What makes many people concerned about the hissing sound from the gas tank when they open the gas cap is that the noise is not there most of the time.
In fact, you can drive a car for 5 years and never hear the noise. Then one day as the gas station attendant is opening your gas tank cap, the hissing noise is heard.
The hissing sound from the gas tank can be caused by the:-
- Normal pressure builds up in the gas tank.
- Leakage from the gas tank.
- Leakage from the evaporative emissions system
Normal Pressure Build Up in the Tank.
Modern gas tanks operate under negative pressure. As a measure to combat climate change, the government came up with regulations for car manufacturers to follow to limit the number of hydrocarbons released into the environment. This led to the sealing of gas tanks and engines burning unburned hydrocarbons.
This leads to negative pressure in the gas tank. While driving, the tank’s pressure will lower, meaning there is higher pressure on the outside than on the inside. The hissing sound you hear when you open the fuel cap is air rushing in to bring balance to the internal and external pressure.
One should note that the hissing sound does not always have to come out. One of our readers was wondering if there is anything wrong with their fuel tank since they have never heard the hissing sound.
Most drivers have confirmed that they only hear the hissing sound when they drive for a while on low fuel and pull into the petrol station to refill.
If you hear the hissing sound when you open the fuel cap and the check engine light is on, you may need to investigate further, as this may be a sign of leakage from the gas tank or evaporative emissions system.
Leakage From the Gas Tank.
This hissing sound from the gas tank may be a sign of fuel leakage. Fuel leaking from the tank may lead to a buildup of negative pressure. Opening the gas cap leads to compensation for the pressure, hence the hissing sound. However, fuel leakage from the gas tank has other signs, such as the smell of fuel throughout. The smell is there, even if there are no fuel stains around the tank or on the road.
Leakage from the Evaporative Emissions System.
Leakage from the evaporative emissions system can lead to a hissing sound when you open the fuel cap. This is due to the loss of pressure in the system. However, leakage from the evaporation emissions system will be accompanied by the check engine light on the dashboard.
What To Do If You Hear a Hissing Sound From Your Gas Tank
If you hear a hissing sound from your gas tank when you open it, it is important to take action. While the sound is often harmless, it can be a sign of a more serious problem. Here are the steps to follow if you hear a hissing sound from your gas tank:
- Check for other signs of trouble: If you hear a hissing sound from your gas tank, check for other signs of trouble. Is there a smell of fuel? Is your check engine light on? Are you experiencing decreased performance in your vehicle? These can be signs of a more serious problem and should be addressed immediately.
- Inspect the gas tank: Look for any signs of leakage around the gas tank. Check for fuel stains or puddles under the car or around the tank. If you suspect a fuel leak, do not start your car and seek professional help immediately.
- Check the evaporative emissions system: If you suspect a problem with the evaporative emissions system, you may need to have it inspected by a mechanic. They can use a special tool to check for leaks in the system and make any necessary repairs.
- Tighten the gas cap: If you hear a hissing sound when you open your gas cap, try tightening it to see if the sound goes away. A loose gas cap can cause pressure to build up in the tank, leading to a hissing sound.
- Don’t panic: Remember, in most cases, a hissing sound from your gas tank is completely normal. Don’t panic if you hear it. Just be aware of any other signs of trouble and take action if necessary.
Frequently Asked Questions
Q: Is a hissing sound from my gas tank normal?
A: Yes, a hissing sound from your gas tank when you open the gas cap is normal. It is caused by the release of pressure in the tank.
Q: Should I be concerned if the hissing sound continues after I open my gas cap?
A: Yes, if the hissing sound continues after you open your gas cap, you should be concerned. This can be a sign of a more serious problem, such as a fuel leak.
Q: Can a loose gas cap cause a hissing sound?
A: Yes, a loose gas cap can cause pressure to build up in the gas tank, leading to a hissing sound. Try tightening the gas cap to see if the sound goes away.
Conclusion
If you hear a hissing sound from your gas tank when you open it, don’t panic. In most cases, this is a completely normal sound caused by the release of pressure in the tank. However, if the sound continues after you open your gas cap, or if you notice other signs of trouble such as a fuel smell or decreased performance in your vehicle, you should take action. Check for leaks around the gas tank, have your evaporative emissions system inspected, and tighten your gas cap. And if you’re ever in doubt, don’t hesitate to seek professional help.
