[spexc31]

i drive a camry v6 '99.
whenever i open my gas tank cap, i hear this hissss sound as im turning off the cap.
is this normal??

by the way, i get horrible gas mileage ><;

[ghost]

if its when your taking off ur gas cap its normal.

Its from the pressure built up in ur gas tank

[azn akira]

yeah its normal, its just the gas vapors that have built up

[ZiGeNX77]

i drive a camry v6 '99.
whenever i open my gas tank cap, i hear this hissss sound as im turning off the cap.
is this normal??

by the way, i get horrible gas mileage ><;

Refer to this thread about your bad gas mileage:

horrible gas mileage =\

[panda]

yes. it is normal.

basically it's a vacuum inside the gas tank which sucks in air once the gas cap is popped open. happens usually when you're really really low on gas.

[taoh]

yes. it is normal.

basically it's a vacuum inside the gas tank which sucks in air once the gas cap is popped open. happens usually when you're really really low on gas.

Isn't fuel vapor under pressure in a fuel tank? It's supposed to happen as long as it is warm enough for fuel to be in a vapor state.

[panda]

Isn't fuel vapor under pressure in a fuel tank? It's supposed to happen as long as it is warm enough for fuel to be in a vapor state.

i don't know if it's just me, but the hiss is audible when i am very very low on fuel... hence, made me believe the sound is due to vacuum. i could be wrong though *shrug*.

[kpopdragon]

hmm, the hissing sound should be your fuel tank under pressure, mostly under the heat when gas is in it's vapor form.

That's also why it's better to pump gas when it's cool so when you won't lose gas as you pump and paying an extra couple of bucks that isn't in your tank

[Bboy Stan]

I got the same car as you and same year ...but yea...I get bad gas mileage too