Why does my Suzuki Mehran make a hissing sound when I open the fuel cap?

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Why does my Suzuki Mehran make a hissing sound when I open the fuel cap?

Every time I open the fuel cap on my Mehran, I hear a noticeable hissing sound. Could this be a sign of a cracked fuel cap o r a problem with the fuel tank pressure? Should I be worried about this issue?

Gari Specialist asked on 17 Apr 2025 12:35:57 pm

1 Answer

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Gari Master - on 17 Apr 2025 12:44:57 pm

A hissing sound when you open the fuel cap is typically caused by a pressure difference in the fuel tank. The fuel tank is designed to maintain a certain level of pressure. When you open the cap, the release of built-up pressure causes the sound. While this can be normal, if the sound is very loud o r persistent, it could indicate:

A faulty o r cracked fuel cap, which is not sealing properly and letting air into the system.

A malfunctioning EVAP system o r vent valve that is not regulating pressure correctly. If this is happening regularly, inspect the fuel cap for damage, and if necessary, replace it to prevent any fuel vapors from escaping.