VELOSTER(FS) >2013 > G 1.6 T-GDI > Emission Control System > Evaporative Emission Control System > Fuel Filler Cap>Description and Operation  
Description
A ratchet tightening device on the threaded fuel filler cap reduces the chances of incorrect installation, which seals the fuel filler. After the gasket on the fuel filler cap and the filler neck flange contact each other, the ratchet produces a loud clicking noise indicating the seal has been set.