Gates 31640 Fuel Tank Cap

OE Equivalent Fuel Cap for Classic Ford and Mercury

The Gates 31640 is an OE Equivalent Fuel Cap built for a secure, factory-style seal on select classic vehicles. It is a vented anti-surge fuel tank cap with rugged construction and OE performance sizing for shallow cam filler necks.

Compatible With 1953-1970 Chevrolet, Ford, Lincoln, Mercedes-Benz, Mercury, and Pontiac applications listed below, including Ford Thunderbird, Mercury Cougar, and Chevrolet Corvette fitments.

• OE Equivalent Fuel Cap with OE performance comparison rating
• Vented anti-surge design for the specified applications
• Fits shallow cam filler necks
• Heavy-duty construction for fuel tank sealing service
• Thread diameter: 1.5 in.; shell diameter: 2.53 in.; depth: 1.38 in.
• Non-lockable design

Product Details and Fitment

This Gates fuel tank cap is engineered to meet or exceed OEM specifications for the listed vehicles. The Gates 31640 is specified for shallow cam filler necks and is listed as vented anti-surge, making it a direct replacement choice for classic Ford Thunderbird, Mercury Cougar, Mercury Marquis, Pontiac Bonneville, and Chevrolet Impala applications where the original cap style matches the catalog fitment.

This part cross-references ATP RG-40 and Four Seasons 46114 for the same application.

What This Fuel Cap Helps Address

• Fuel odor from a cap that no longer seals properly
• Evaporative fuel loss caused by a worn or incorrect cap
• Driveability issues related to a damaged or mismatched filler-neck seal
• Fuel tank pressure irregularities on vented anti-surge applications
• Replacement needs for original-style caps on classic Chevrolet, Ford, Mercury, Pontiac, Lincoln, and Mercedes-Benz models

Installation Notes and Tips

Verify filler-neck style before ordering. This cap is listed for shallow cam filler necks and specific OE-equivalent applications, so match the vehicle year, make, model, and notes exactly. Confirm the cap type, venting style, and dimensions against the original part before installation. For best results, inspect the filler neck for wear, corrosion, or damage that could affect sealing.

Quality Assurance

Gates OE Equivalent Fuel Caps are built with heavy-duty construction and are specified to meet or exceed OEM requirements for the listed applications. Part number 31640 is cataloged as an OE performance replacement for the vehicles shown in the fitment data.