[FIXED] Gas Tank Leaks When Full

[Stephen Carney]

I am helping my mom with her 2003 Hyundai Elantra. One problem she has experienced is that she says if she fills the gas tank up the whole way, gas will leak out onto the ground. She only fills up about halfway now. It wouldn’t be a problem except the car cant pass emissions because it has two codes, P0456 – EVAP System Leak Detected(very small leak), and P0442 EVAP System Leak Detected(small leak). Any ideas on why the gas is leaking when the tank is full. Do you think the two MIL codes are related to the issue. Any ideas? Thanks.

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[college man]

[quote=”scarney” post=182455]I am helping my mom with her 2003 Hyundai Elantra. One problem she has experienced is that she says if she fills the gas tank up the whole way, gas will leak out onto the ground. She only fills up about halfway now. It wouldn’t be a problem except the car cant pass emissions because it has two codes, P0456 – EVAP System Leak Detected(very small leak), and P0442 EVAP System Leak Detected(small leak). Any ideas on why the gas is leaking when the tank is full. Do you think the two MIL codes are related to the issue. Any ideas? Thanks.[/quote]

Your going to have to inspect the tank and associated lines. Since you have evap codes you
could have a problem with the charcoal canister. I think the best bet would be to fill the car almost
to the point of leaking. Get it home and add 5 gallons or until it starts to leak. Have it up on jack stands
or ramps to get under there and see where the leak is.

https://www.ericthecarguy.com/faq/finding-and-fixing-leaks/finding-and-fixing-leaks

[Juan]

Had the same problem minus the MIL codes on my friend’s 94 Accord, turned out to be the fuel filler neck, rusted out like Swiss cheese. Might also fix the code in your case. Almost bought it used from a junk yard but didn’t. $83 new at local parts store.
Good luck

[Stephen Carney]

It also turned out to the be fuel filler neck on her car. On my 1996 Honda Accord, it is behind a plastic cover in the wheel well. In my mom’s Elantra, it’s not behind a cover so it is more exposed to the elements. There were several spots that were completely rusted out. I replaced the filler neck and the EVAP codes are good as gone. The tank can now be completely filled as well. Thanks to everyone for their help.

[Author]

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