Fuel Delivery
Fuel Tank Cap
A fuel tank cap seals the filler neck so fuel vapor stays in the system and dirt stays out. We carry 133 gas caps from $4 to $149 for vehicles from 1966-2023, from Motorcraft, Gates, AC Delco and Stant, with many fits for the Ford F150, Super Duty trucks, Mustang and Chevrolet Camaro.
Shop fuel tank cap by vehicle
Motorcraft Fuel Tank Cap W0133-1702139 for Ford F250 Super Duty
Fits 2003–2004 models
Why the gas cap matters
On vehicles with evaporative emissions controls, the cap is part of a sealed system. A worn seal or a cap that does not click tight can set an evaporative leak code and turn on the check engine light. Older vehicles may use vented caps that let air in as fuel is used.
Signs of a bad cap include a fuel smell near the filler, a loose fit, a cracked or flattened rubber seal, and a cap that will not ratchet.
Locking, venting and style
This category includes non-locking caps and locking caps with keys, plus twist-lock styles. Venting type matters: emission control caps and vacuum-only vented caps are built for different systems, so pick the type listed for your vehicle.
Some trucks, such as Ford Super Duty models with dual tanks, list left and right caps. Colored caps, such as yellow on some diesels, help mark the correct fuel.
Fitment notes
Caps vary in thread style and diameter, even within one brand. Use the vehicle selector and check year and fuel type. If your vehicle has a capless filler, you will not need a cap for the main opening.
After fitting a new cap, a stored evaporative code may take a few drive cycles to clear on its own, or you can clear it with a scan tool once the leak is fixed.
Fuel Tank Cap questions
Can a loose gas cap turn on the check engine light?
Yes. On vehicles with evaporative emissions monitoring, a loose or worn cap can set a leak code. Tighten or replace the cap, then allow a few drive cycles for the light to clear.
Is a locking gas cap worth it?
A locking cap helps deter fuel theft and tampering. Make sure it is the correct vented or sealed type for your vehicle, and keep the spare key somewhere safe.
Are all gas caps the same size?
No. Thread pitch, diameter and venting differ between vehicles. Choose your year, make and model in the selector to see caps listed for your filler neck.