Fuel caps prevent dirt, debris, and dust from entering the gas tank, as well as provide a reliable seal for the fuel lines. Gas caps that do not tighten properly or break during refueling should be replaced to avoid the vehicle's check engine light from coming on.

Locking gas caps add a layer of security, and help prevent fuel and oil theft. Fuel caps prevent dirt, debris, and dust from entering the gas tank, as well as provide a reliable seal for the fuel lines. Gas caps that do not tighten properly or break during refueling should be replaced to avoid the vehicle's check engine light from coming on.