Fuel tank for a vehicle comprising a filler neck for receiving a diesel fuel filler nozzle

The motor vehicle fuel tank has a filler stub pipe (1) with a diameter to receive a larger filler pistol (2) for Diesel fuel. The filler has a pivoting closure flap (3) to prevent insertion of a smaller diameter filler pistol. The flap prevents connection between the filler stub and tank interior when closed, and has a locking hook (5) to fold it closed. The hook is released by insertion of a large diameter filler pistol.