vented or sealed?

[Mac]

I've been noticing a odour of gasoline from the rear of my Vette, especially when the tank is above half-full. After searching all the usual suspects, I was about to give up when I noticed my gas cap seal was chewed up looking. As soon as I touched it, the seal disintegrated. I'm thinking I'm onto the problem...

When I visited my local supplier about getting a seal, he pulled out "the book" and told me I had the wrong gas cap. I had a vented cap and apparently, I should have a sealed cap for a 73 w. L82. Hmmm...

I did a bit of online digging but, strangely enough, there isn't a whole lotta information about Corvette specific gas caps out there. The closest I could find was that Chevy changed to a different style in 1975 but both vented and sealed were available for 1969 through 1974. ;help

-Mac

 

[petes74ttop]

Gas Cap

Your 73 came with a sealed non vented gas cap. There are 4 rubber gas lines at the tank one into the vapor return and the other into the tank those are one the left side of the tank, you also have two more lines on the right side of the tank, the feed to the pump and the return from the pump. See if they might need to be replaced. You can change them with the tank in place. Your carb will also everaperate a lot of gas when you shut it off, you may just be smelling the fuel evaperating from the carb.
Is your evaperator canistor hooked up? PG.

 

[Vette79]

Good question! It might be your vapor canister if you have one.

 

[Vettehead Mikey]

Your 73 came with a sealed non vented gas cap.

Yup, sealed is correct.

 

[Mac]

Your 73 came with a sealed non vented gas cap.

Well, there's one problem fixed. I bought/installed an OEM sealed gas cap.

Maybe that's my problem solved in a nutshell. Between being vented and having a seal which was compromised, the old gas cap can't have been doing much. Next time I fill up, I'll know if I've solved it!

Thanks for all the other suggestions! All of the hoses looked clean and dry to my inexpert eye and the smell was localized to the tail of the car so unlikely to be the canister or carb. If a fill-up proves me wrong, I know what to look at next.

-Mac

 

[Vettehead Mikey]

Mac,

Another possibility is the gas/vapour separator on the top left of the gas tank, almost directly above the drivers side muffler. One of the nipples might have cracked allowing gas to drip. Your mention of it happening when the tank is more than half full made me think of this.

 

[Mac]

Mac,

Another possibility is the gas/vapour separator on the top left of the gas tank, almost directly above the drivers side muffler. One of the nipples might have cracked allowing gas to drip. Your mention of it happening when the tank is more than half full made me think of this.

Here's to hoping the sealed cap is my solution but you're right- that's another possibility I didn't check.

-Mac

 

[Crimson Thunder]

One other place to check is the gasket between the filler neck and the tank.That is where my fuel smell was coming from and it took me forever to find it.