gas odor

granny99

What can cause a gas smell after the car has been running and then turned off?

imidazol97

A leak in the fuel tank itself.

A leak in the rubber piping or tubing around the gas tank, in some cases due to rusting
from winter salts. Because these lines stay under pressure after the car is shut off, until
the leak reduces the pressure and the leak stops, this can drip for a while after car is shut off.

A carbon cannister at the tank end of the car is supposed to have the gas tank vented
through it so the carbon captures the fumes. That cannister may be worn out and not
capturing the fumes. When the car is running the emissions
system opens the purge valve and pulls air in through the cannister and through the tank
and on into the engine to be burned. This prevents hydrocarbons from polluting the air as much.

It helps to stop the car and do some sniffing around the car when there's almost no wind to see
where the fumes are coming from. If the smell is from under the hood, the leaking may be there
and of course that's an emergency to have it checked out in case there's a leak in the tubing
there or on a seal where the tubes connect to other things.