# Black smut

**URL:** <https://community.cartalk.com/t/black-smut/39350>\
**Category:** Maintenance/Repairs\
**Tags:** qx4, infiniti\
**Created:** [November 11, 2009, 8:18pm UTC](https://community.cartalk.com/t/black-smut/39350 "2009-11-11T20:18:21Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![doriscar1](https://avatars.discourse-cdn.com/v4/letter/d/0ea827/32.png) [@doriscar1](https://community.cartalk.com/u/doriscar1)\
**Post date:** [November 11, 2009, 8:18pm UTC](https://community.cartalk.com/t/black-smut/39350/1 "2009-11-11T20:18:21Z")

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I have black smut forming around gas cap

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**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\
**Post date:** [November 11, 2009, 8:26pm UTC](https://community.cartalk.com/t/black-smut/39350/2 "2009-11-11T20:26:10Z")

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The seal on the gas cap may be breaking down. Replacing it is cheap.

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**Author:** ![doriscar1](https://avatars.discourse-cdn.com/v4/letter/d/0ea827/32.png) [@doriscar1](https://community.cartalk.com/u/doriscar1)\
**Post date:** [November 12, 2009, 4:26pm UTC](https://community.cartalk.com/t/black-smut/39350/3 "2009-11-12T16:26:52Z")

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Thought about problem with gas cap, but when I remove gas cap it makes a sound like the gas tank is under a vacuum. Could it be breaking down if I hear noise?

Thanks

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [November 12, 2009, 5:00pm UTC](https://community.cartalk.com/t/black-smut/39350/4 "2009-11-12T17:00:22Z")

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The black smut is coming off the black rubber seal for the fill neck to the gas tank.

Take some silicone spray lubricant and soak a paper towel and wipe the seal down to remove the smut and to prevent it from causing more.

Tester

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**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\
**Post date:** [November 12, 2009, 5:35pm UTC](https://community.cartalk.com/t/black-smut/39350/5 "2009-11-12T17:35:59Z")

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Is your car getting hard to fill rapidly with gas? If it is then the hissing sound could be from a bad vent on your gas tank. If you can fill it normally then it is nothing to worry about.