# My gas cap failed the leak test: is there any hope for it? **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [February 16, 2019, 7:09pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757 "2019-02-16T19:09:48Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Triedaq](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@Triedaq](https://community.cartalk.com/u/Triedaq)\ **Post date:** [February 19, 2019, 1:44am UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/21 "2019-02-19T01:44:47Z")
Oh, but you have to give Troll credit for his efforts. In my 77 years of life, I have never put in as much time reading about gas caps until I read this thread. ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [February 19, 2019, 2:44pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/22 "2019-02-19T14:44:21Z")
> [@eddo](#): > > can you take the seal off your non locking one and put it on your locking one? It has no separate gasket. That’s part of what made me suspicious. This cap has a ‘safety vent’, which the older cap lacks: maybe that’s what’s leaking. > [@TwinTurbo](#): > > The proof is in the pudding, the cap failed their test… I don’t know why it failed. > [@db4690](#): > > I really don’t understand why Troll is tearing his hair out about this I’m not tearing my hair out. I just asked a question. I didn’t expect a kind of _Spanish Inquisition_!!! ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [February 19, 2019, 2:58pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/23 "2019-02-19T14:58:18Z")
![](https://global.discourse-cdn.com/cartalk/original/2X/9/9bb9bc6c1fde10a480fb4b6a71bfa985a4527c4f.jpeg) ---
**Author:** ![Whitey](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/whitey/32/24680_2.png) [@Whitey](https://community.cartalk.com/u/Whitey)\ **Post date:** [February 19, 2019, 3:04pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/24 "2019-02-19T15:04:12Z")
Nobody expects the _Spanish Inquisition!!!_ ![nobody-expects-the-spanish-inquisition](https://global.discourse-cdn.com/cartalk/original/2X/9/9b37844b0d019c7b40e02c856ffb0680f4915d26.jpeg) …and I don’t like Spam!! ![I%20don't%20like%20spam](https://global.discourse-cdn.com/cartalk/original/2X/2/24c7c9bd28c8a061d56fff825a53308fe729c703.jpeg) ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [February 19, 2019, 4:08pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/25 "2019-02-19T16:08:09Z")
> [@RandomTroll](#): > > I don’t know why it failed. So the replacement cap had a vent that the OEM cap did not? You asked if the gasket matters. It does. The fact your replacement cap could be leaking from the safety vent has no bearing on whether or not the seal on the gas cap is necessary. If the seal wasn’t needed, it wouldn’t be there. On this particular cap, the leak can be from at least two different sealing mechanisms. But for $10 who really cares which one it is? It doesn’t change the situation does it? You need a new cap. I’d suggest an OEM equivalent this time around… ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [February 20, 2019, 3:49am UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/26 "2019-02-20T03:49:01Z")
I’m advocating for OP trying to fix it myself … where’s the fun in just buying a new one? ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [February 20, 2019, 3:47pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/27 "2019-02-20T15:47:24Z")
How much does an emission test cost there George? Around here, we get one free re-test. After that, you pay again. Sorry, I’m as frugal as the next but I’m not risking my free re-test on a guess. Then your $10 cap becomes $55+. Not to mention, the rest of the non-OEM compliant cap is probably 20 years old. Replace the vent seal and then the neck o ring fails. Having fun now? Over $10… ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [February 20, 2019, 4:13pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/28 "2019-02-20T16:13:27Z")
If the gas-cap is truly failing it should/would generate an error code…something like a P0442. ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [February 20, 2019, 9:59pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/29 "2019-02-20T21:59:28Z")
> [@MikeInNH](#): > > If the gas-cap is truly failing it should/would generate an error code…something like a P0442. We’re talking about an 87 Toyota, long before ODBII codes ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [February 21, 2019, 1:59am UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/30 "2019-02-21T01:59:38Z")
> [@TwinTurbo](#): > > How much does an emission test cost there George? It costs about $60. Usually you get a free test, but you have to get that in writing before the first test I discovered. One time I had been using a shop for years that even had a sign on the wall saying second test is free, but when I pointed that sign out the tech after he billed me for a rare second test he just ripped the sign off the wall and threw it in the garbage can … lol … no argument common sense says to buy a new cap. But I think its fixable and the fix (if all appeared well on disassembly and re-assembly would be a pretty low risk to fail a cap test). Another possibility is to buy a new cap just for testing, and use the repaired old cap otherwise. Then you’d always be using a new cap for the test. ---
**Author:** ![Triedaq](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@Triedaq](https://community.cartalk.com/u/Triedaq)\ **Post date:** [February 21, 2019, 2:11pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/31 "2019-02-21T14:11:32Z")
I would just cap things off by purchasing a new cap. ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [February 21, 2019, 4:27pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/32 "2019-02-21T16:27:06Z")
> [@George\_San\_Jose1](#): > > Another possibility is to buy a new cap just for testing, and use the repaired old cap otherwise. Then you’d always be using a new cap for the test. You can’t be serious. When was the last time you had a gas cap fail? They last dozens of years. This isn’t a precious treasure that needs protecting. The term frugal to a fault seems appropriate here… ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [February 21, 2019, 4:48pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/33 "2019-02-21T16:48:03Z")
> [@TwinTurbo](#): > > When was the last time you had a gas cap fail? I’ve had to replace the cap on my wifes 07 Lexus once. Replaced cap on my 05 4runner. But both generated codes. ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [February 21, 2019, 4:50pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/34 "2019-02-21T16:50:47Z")
Keep in mind that a bad purge valve can generate the code as well. But as @It_s_Me pointed out, those codes aren’t gonna be generated on an '87. 😉 ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [February 21, 2019, 4:57pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/35 "2019-02-21T16:57:38Z")
Did you ever have to replace them again in the time you owned those vehicles? That’s the point. Buying a new cap to use only at the test and then running around on the old one that doesn’t work properly anymore- does that make any sense to you? ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [February 21, 2019, 5:24pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/36 "2019-02-21T17:24:10Z")
> [@TwinTurbo](#): > > Did you ever have to replace them again in the time you owned those vehicles? Once. For the 4runner I went to ADAP (They were open on Sunday). 1 week later getting code again. This time I went to dealer. Never had the error again. ---
**Author:** ![Triedaq](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@Triedaq](https://community.cartalk.com/u/Triedaq)\ **Post date:** [February 22, 2019, 4:05am UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/37 "2019-02-22T04:05:44Z")
One option on the 1949 Nash was a gas cap that flipped open when one pushed a button on the dashboard. This was an option. It operated electrically. It wasn’t a door with a gas cap behind it. It was an exterior gas cap. That, to me was the ultimate in gas caps. ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [February 22, 2019, 4:34pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/38 "2019-02-22T16:34:28Z")
> [@Triedaq](#): > > on the 1949 Nash was a gas cap that flipped open when one pushed a button on the dashboard. T Did it seal? In 1949, gas tanks weren’t sealed, so the caps didn’t need to be. ---
**Author:** ![Triedaq](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@Triedaq](https://community.cartalk.com/u/Triedaq)\ **Post date:** [February 22, 2019, 4:36pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/39 "2019-02-22T16:36:39Z")
Probably not. I just remember the our neighbors 1949 Nash Ambassador with this electric gas cap. ---
**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\ **Post date:** [February 22, 2019, 5:50pm UTC](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757/40 "2019-02-22T17:50:33Z")
What do you think of the modern capless designs? I have yet to use one but it seems like a good improvement. Honda even includes a special funnel for filling from a can if that’s necessary at some point. [Previous page](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757.md?page=1) [Next page](https://community.cartalk.com/t/my-gas-cap-failed-the-leak-test-is-there-any-hope-for-it/134757.md?page=3)