What to Do When There's a Suction Sound When Opening the Fuel Tank Cap?

[VonSamantha]

When there's a suction sound upon opening the fuel tank cap, the charcoal canister or solenoid valve should be checked. Here are additional details: 1. A malfunction in the charcoal canister or solenoid valve can cause the pressure inside the fuel tank to be lower than the external pressure, resulting in a suction sound. 2. Occasionally hearing a suction sound is normal, but frequent occurrences require inspection and repair at an auto repair shop. 3. Generally, the charcoal canister in a car's fuel tank helps balance internal and external pressure. If the charcoal canister malfunctions, the fuel tank cap loses its pressure relief function, leading to pressure imbalance. 4. When the internal pressure of the fuel tank is lower than the external pressure, it can cause deformation and damage to the tank. Severe deformation may prevent fuel from being added, leading to inability to refuel and potential long-term damage to the fuel pump.