2001 Cadillac Catera – check valve device in fill tube

Dear Doctor: I own a 2001 Cadillac Catera. My gas gauge showed a quarter tank of fuel remaining so I stopped to fill up, but the gas would not go into the tank. It filled up the filler tube and shut the nozzle off. A mechanic thought that there was an anti-siphon or check valve in the fill tube that was probably stuck. I beat on the tube several times and then was able to fill up. Is there a check-valve device in the Catera fill tube? Norman


Dear Norman: All vehicles have some sort of anti-siphon device either at the gas tank inlet or bottom of the fill tube. This is a basic device to prevent gas spill in a rollover and gas backing up the fill tube. In some cases the valve is part of the fuel tank and cannot be purchased separately.