GAS TANK, PRESSURE Options

[trex6g]

WHEN I GO TO PUT GAS IN MY CELICA,ON REMOVING THE GAS CAP I HAVE A LOT OF PRESSURE RELEASE FROM THE TANK ,IS THIS NORMAL?


THANKS TREX6G

[DEATH]

I can tell you it happens often with several vehicles I've owned but not sure what the reason is. Obviously it's built up vapors from gas but why it does it sometimes and not others IDK.
Maybe someone on here knows the full scoop.

[samir0189]

I have the same problem. I think its more of a vacuum of the tank pulling in air than the tank blowing out air. I want to believe, but i could be wrong, that its similar to a 20oz soda bottle - if you go to chug the bottle and don't allow for air to be exchanged back into the bottle in place of the fluid, the bottle gets all "sucked in." and then when you stop drinking, it sucks back in all that air. I think the tank is doing the same thing, sucking back in air, because the gas cap creates an airtight seal, so no fumes escape. could be wrong ... but its a guess. =\

[presure2]

it is 100% normal.

[GriffGirl]

Not only is it 100% normal, (and not a "problem") but I think it even has a warning label on the back of the gas door that says to remove the cap slowly to allow the pressure to release. In fact, if that pressure didn't build up, you'd notice by getting crappy mileage (not sure why, but it's true) and could even have weird issues like a CEL (on newer cars at least)

[CelicaST_CALI]

it happens to me,especially on hot days..

[Remy]

Not only is it 100% normal, (and not a "problem") but I think it even has a warning label on the back of the gas door that says to remove the cap slowly to allow the pressure to release. In fact, if that pressure didn't build up, you'd notice by getting crappy mileage (not sure why, but it's true) and could even have weird issues like a CEL (on newer cars at least)

It also means you have a bad gas cap gasket, if you don't have pressure when you release the cap then its time to replace the gasket. Oh and yes gas/water does evaporate so not having any pressure when you release the cap can lead to less mpg you could say.

[RickJamesBish]

Yeah, it happens all the time.

[delusionz]

this is basic science... if u suck on a waterbottle and then close the cap before it has a chance to replace the water with oxygen (fuel pump/injector effect) ... air will rush straight in when u open it up again (gas cap effect) ... u dont really want oxygen in your tank as it helps the gasoline go stale and ull be hitting air bubbles when ur on the last drop, so the bigger the pressure release the better, just open your cap and fill up when you run out, try avoid lots of fills while you already have gas.