8 years ago in CHEVROLET
I've noticed lately that when I remove the gas cap on my 1964 Impala, there is a hiss of pressure. I have a vented gas cap & wondering if this is a serious issue.
Answers (2)
The cap should say on the top if it is vented or convented. If you have an inlet hose to fuel pump and one outlet at the pump it has to have a vented cap. If it has three hoses that is a closed system and the third fuel line is used for venting.
I suggest you buy and new vented gas cap. The one you have now has to be bad or it wouldn't build pressure in the tank. Or if the one you have is new... it's no good or it was boxed wrong.