Gates 31780Y Fuel Tank Cap

Gates Flex Fuel Locking Fuel Cap

The Gates 31780Y is a flex fuel regular locking fuel cap built for vehicles that use gasoline or E85 ethanol. Its yellow cover and E85 designation make the fuel type easy to identify, while the locking design adds an extra layer of security at the filler neck.

Compatible With select Chevrolet, GMC, Nissan, Toyota, Buick, Cadillac, and GMC truck and SUV applications, this fuel tank cap is a direct-fit service part for threaded filler neck systems. The Gates Flex Fuel Regular Locking Fuel Cap line is designed to help drivers quickly recognize flex-fuel capability without changing the vehicle’s original fueling setup.

Key Features

• Part number: 31780Y
• Lockable fuel tank cap for added security
• Yellow cap with E85 designation for flex fuel identification
• Threaded cam type for threaded filler neck applications
• Pressure-vacuum venting
• Shell diameter: 2.91 in.
• Thread diameter: 1.77 in.
• Depth: 2.61 in.
• Color: Yellow

Detailed Product Overview

This Gates fuel tank cap is part of the Flex Fuel Regular Locking Fuel Cap product line, which uses a yellow plastic cover and clear E85 marking to indicate that the vehicle can use gasoline or E-85 ethanol. The 31780Y is built for threaded filler neck applications and uses pressure-vacuum venting to match the needs of the fuel system. It is a practical replacement for drivers servicing flex-fuel Chevrolet Silverado, Tahoe, Equinox, GMC Sierra, Yukon, Nissan Armada, Nissan TITAN, and Toyota Tundra or Sequoia models listed in the fitment data.

This part cross-references Stant 10504Y for the same application.

What This Fuel Cap Helps Address

• Missing or damaged locking fuel cap
• Fuel cap warning light caused by a poor seal
• Worn threaded cap that no longer tightens correctly
• Loss of fuel system sealing at the filler neck
• Incorrect fuel identification on flex-fuel vehicles

Installation Notes and Tips

Verify the filler neck is threaded before installation. Match the cap dimensions and venting style to the original unit, and confirm the cap locks and seals properly after tightening. For fitment, use the vehicle-specific listings for models such as the 2015 Chevrolet Equinox, 2014 Chevrolet Silverado 1500, 2012-2015 Nissan Armada, and 2009-2013 Toyota Tundra.

• Fits 2015 Chevrolet Equinox, N/A
• Fits 2012-2015 Nissan Armada, N/A
• Fits 2014-2015 Nissan TITAN, N/A
• Fits 2014 Chevrolet Silverado 1500, N/A
• Fits 2014 GMC Sierra 3500 HD, N/A
• Fits 2009-2013 Toyota Tundra, N/A
• Fits 2012-2013 GMC Sierra 1500, N/A
• Fits 2012-2013 Chevrolet Express 2500, N/A
• Fits 2004 Chevrolet Tahoe, N/A
• Fits 2004 GMC Yukon XL 1500, N/A

Quality Assurance

Gates is a recognized name in automotive fuel system service parts, and this cap is built to meet the dimensional and functional requirements listed for the application. Use the part number 31780Y and the vehicle fitment details to confirm the correct replacement before installation.