Black smut

Maintenance/Repairs
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1

I have black smut forming around gas cap

2

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

3

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

4

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

5

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.