GM GENUINE PARTS Fuel Tank Filler Cap GT359 (22921366) Yellow E85, Rubber Gasket, Locking Option

GM Genuine Parts GT359 (22921366) is an original-equipment E85 yellow fuel tank filler cap designed to seal the fuel filler neck, keep contaminants out, and clearly identify FlexFuel vehicles.

This replacement fuel tank filler cap is produced to GM factory specifications for fit, function, and durability. It includes a rubber gasket for a liquid-tight seal that prevents fuel evaporation, water infiltration, and debris entry. The bright yellow color signals E85 compatibility to owners and service technicians, and the cap is offered in locking and non-locking versions to match your vehicle’s security features.

How does this cap protect my vehicle’s fuel system?

The GM Genuine Parts GT359 cap forms a snug, threaded seal at the filler neck to reduce vapor loss and keep contaminants out. The integrated rubber gasket maintains a reliable liquid- and vapor-tight barrier under normal driving conditions.

• Threaded design for consistent engagement with the filler neck
• Rubber gasket prevents leaks and blocks dirt, water, and debris
• Reduces fuel evaporation and helps maintain system pressure

Why is the yellow color important for E85 vehicles?

The bright yellow cap visually indicates E85 (flex-fuel) compatibility so users and service personnel can quickly identify the correct fuel type. This reduces the chance of misfuelling and helps preserve engine and emissions system integrity.

• High-visibility color marks FlexFuel capability at a glance
• Helpful for drivers, gas station attendants, and technicians
• Matches GM’s recommended specification for E85-equipped models

Can I choose a locking or non-locking version, and when should I pick locking?

The GT359 is available in both locking and non-locking configurations. Choose the locking cap if you need extra theft protection or if your original cap used a key; select the non-locking version for standard replacement when no key system is required.

• Locking option adds a keyed security feature for fuel access
• Non-locking option provides a direct, simple replacement fit
• Both versions are manufactured to GM’s original equipment standards

Will this cap fit my GM vehicle and how does it compare to aftermarket parts?

The GT359 is produced as a GM Genuine Parts component and engineered to match factory tolerances and materials. That ensures the same fit and expected service life as the original cap, providing a more reliable seal than many generic aftermarket alternatives.

• Factory-style fit to original GM filler neck dimensions
• Materials and gasket designed to meet GM performance requirements
• Recommended by GM as a direct replacement for compatible models

Who is this for: Owners and technicians of GM FlexFuel vehicles seeking a direct OEM replacement fuel filler cap that clearly indicates E85 compatibility. It’s ideal for drivers who prefer factory-fit parts, need a locking option for security, or want to prevent fuel vapor loss and contamination with a purpose-built GM component.