I have a 69 convertible. If I park my car in my driveway or facing uphil,l fuel leaks past the gas cap. I have a locking cap. I believe 69 camaro's came with a plain vented cap. How does a vented cap work? Is there a one way valve or is just open? Has anyone had this problem? Thank Cisco

Vented cap works to allow air to come into the tank to replace the spent fuel, no relief venting from the inside to the outside if fuel vapor expands, as it does.

Turn car around and point the front end down.

Vented cap works to allow air to come into the tank to replace the spent fuel, no relief venting from the inside to the outside if fuel vapor expands, as it does.

Turn car around and point the front end down.


Could someone expand on this? I have the same problem, but not when parking (no hills here) but on normal driving, the lic plate and back of tank are soaked in fuel. Is the cap supposed to prevent fuel from coming out of the tank? Is my cap just defective? Back to the OP's question, how does it work, I don't see any spring to act as a check valve.

thanks

A vented cap acts like a check valve and only allows air in not gas out. Probably just old and sealing surface or ball shot.
Common problem with all first gens.

A vented cap acts like a check valve and only allows air in not gas out. Probably just old and sealing surface or ball shot.
Common problem with all first gens.


thanks. I just got a new "slant" made one from pep boys. hopefully that'll solve it.

thanks again

I had leaking cap on my '68. Replaced cap. Problem gone...............


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