What Causes the Release of Gas When Opening the Fuel Tank Cap?

1 Answers
SanJayce
07/30/25 7:23am
When opening the fuel tank cap, the release of gas is caused by the fact that gasoline is a highly volatile fuel. After being agitated in the fuel tank, gasoline accelerates its evaporation, producing a large amount of fuel vapor, which is a normal phenomenon. Below are additional details: 1. Normal phenomenon: Gasoline in the fuel tank generates a certain amount of fuel vapor due to temperature changes and vehicle movement. Therefore, when the driver opens the fuel filler port, pressure is released, which is normal. 2. Feeling excessive pressure: At this time, it is necessary to check whether the carbon canister is clogged and whether the carbon canister solenoid valve is functioning properly. 3. Reasons for high pressure in the fuel tank: Normally, gasoline vapor is stored in the carbon canister. If the gasoline vapor has nowhere to go and remains in the fuel tank, it will cause high pressure inside the fuel tank.
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