Gates 31859 Fuel Tank Cap

Gates 31859 Regular Locking Fuel Cap

The Gates 31859 is a regular locking fuel cap built for vehicles that need a non-vented fuel tank cap with secure closure and proper tank pressure control. It is a direct-fit style replacement for a wide range of Ford, Lincoln, Mercury, Dodge, and Chrysler applications, including Ford Explorer, F-150, Mustang, and Escape models.

Gates Regular Locking Fuel Cap products are engineered to meet OEM specifications and emission-related requirements. This cap uses a two-way pressure relief and vacuum relief valve to let the fuel tank breathe while helping contain fuel vapors.

Key Features

• Lockable fuel cap for added security
• Regular fuel cap design
• Non-vented construction
• Two-way pressure relief and vacuum relief valve
• Shell diameter: 2.125 in.
• Depth: 1.5 in.
• Gates part number 31859

Product Details

This Gates fuel tank cap is a practical replacement for drivers servicing evaporative system concerns or replacing a worn, damaged, or missing cap. The non-vented design and locking function make it a strong match for vehicles that require controlled tank sealing without fuel vapor escape. It is listed for applications such as the Ford Explorer, Ford F-150, Ford Mustang, Ford Escape, and Lincoln Navigator, along with other confirmed fitments. This part cross-references Four Seasons 35083 for the same application.

Common Issues It Can Help Address

• Loose or damaged fuel cap that no longer seals properly
• Fuel vapor odor around the vehicle
• Check engine light related to evaporative emissions faults
• Difficulty maintaining proper fuel tank pressure or vacuum balance
• Missing or non-locking cap on a vehicle that requires a locking fuel cap

Installation Notes and Tips

Verify the cap style, shell diameter, and non-vented design before installation. Confirm vehicle year, make, and model against the fitment list, especially for Ford Explorer, Ford F-150, and Ford Escape applications. Inspect the filler neck and sealing surface for dirt, corrosion, or damage before installing the cap. After installation, tighten the cap until it locks securely.

Quality Assurance

Gates states that this locking fuel tank cap meets OEM specifications and Federal and State emission requirements. The pressure relief and vacuum relief valve design supports proper tank breathing while helping contain fuel fumes.