Can't Fill the Gas Tank


I am driving my brother’s 2001 Impala (actually as a favor to him). I went to fill the tank yesterday and the gas nozzle keeps clicking off like the tank is full (no, it is not even close to full). I know there is a vacuum that is supposed to be created when filling the tank and it doesn’t appear to be happening. I’ve tried different pumps even different gas stations. I’ve tried putting the gas nozzle in different, pushing it in as far as possible and not putting it in very far (I now have gas scented shoes). It took 10 minutes to get 1/2 a gallon in the car. One suggestion has been that someone tried syphoning gas and the hose broke off. Any help in figuring out the problem and how to fix it without costing me a ton of money (not my car remember) would be great.


This is a common complaint from those people who did not see or ignored the warnings on the car or in the car’s owner’s manual, warring you not to top off the tank when you fill it. It is safer to stop trying to fill it the first time it clicks off.

It means the vent system is malfunctioning. Topping off damages it and that usually requires replacement of the charcoal canister. If may also be a result of a loose or crimped hose or other mechanical problem with the fill system.


Agreed. Probably fouled charcoal cannister. Very expensive to replace.


It’s not the vent system. Just down the pipe from the filler neck is a check valve that is designed to block off the fill-pipe in the event of a rollover accident and prevent the siphoning of fuel from the tank. It’s a simple floating ball type deal. Yours is stuck in the “closed position”. Sometimes you can free it by inserting a 3/8" hose down the filler pipe and manipulate it until it dislodges the ball. The only other cure is to unclamp the fill-pipe and remove the pesky ball that is jammed in it.

This ball momentarily is floated into the closed position every time you fill the tank. 99% of the time, they open again as the fuel drains out of the filler pipe and the ball drops into it’s normal, open, position.