Is it normal for a burst of gas to spray out when opening the fuel tank cap?
4 Answers
Fuel tank cap spraying gas indicates good sealing performance of the fuel tank. Below are relevant introductions: Preparation method: Supporting equipment for gasoline production includes atmospheric and vacuum distillation, catalytic cracking, delayed coking, diesel hydro-upgrading, coker gasoline hydro-refining, catalytic cracking gasoline hydro-desulfurization, continuous catalytic reforming (referred to as reforming), benzene extraction, and MTBE units. Main uses: Gasoline is one of the most widely used light petroleum products and an important fuel for engines; it is mainly used as a power fuel for transportation vehicles. Industries such as rubber, paint, dye, printing, pharmaceuticals, and adhesives use gasoline as a solvent. Gasoline is also used as a degreaser for cleaning machine parts and clothing, as well as for pre-treatment of electroplated products.
As a veteran driver with nearly 20 years of experience, I often encounter fuel tank cap venting. This mainly occurs because gasoline in the tank forms vapor when temperatures fluctuate. In summer, if you park in the sun and then unscrew the cap, this vapor may escape. I've noticed that this happens more frequently after long-distance drives when refueling. A slight hissing sound and minor vapor emission are nothing to worry about, but if it bursts out like opening a soda can or you detect a strong gasoline odor, it might indicate a clogged charcoal canister. My neighbor's car recently had this issue, which was resolved by replacing the charcoal canister at the repair shop. Remember not to overfill the tank when refueling—leave some space for expansion.
I often experience the issue of gas spraying out when opening the fuel tank cap on my own car. It's particularly noticeable when the weather gets warmer—in parking lots, when a line of cars open their caps, seven or eight out of ten will release gas. The principle is quite simple: gasoline turns into a gaseous state when heated, building up pressure inside the fuel tank. Opening the cap releases this pressure, much like opening a soda bottle. If it happens occasionally, it's no big deal, but if every time you unscrew the cap it sounds like lighting a gas stove with a puffing noise, it's highly likely that the charcoal canister is malfunctioning. That time, I even went out of my way to test the fuel tank pressure, and sure enough, it was abnormally high. Later, the mechanic cleaned the charcoal canister filter and checked the fuel lines, and everything returned to normal.
Last time I refueled, a puff of white gas sprayed out from the fuel tank cap. I specifically asked my friend at the repair shop about it. He said that fuel vapor evaporation in high-temperature environments is a natural phenomenon, especially when refueling a hot car. However, if you notice a strong gasoline smell or the engine warning light comes on at the same time, you should be alert. I tried a folk remedy: parking the car in a shaded area for half an hour before opening the cap, and basically, no gas sprayed out. Also, be careful not to overfill the tank when refueling; leaving about 1/4 of the tank empty can reduce fuel pressure. During my recent car maintenance, I specifically asked the mechanic to check the carbon canister system. He said the filter should be replaced regularly, otherwise carbon buildup can cause abnormal fuel tank pressure.
