JYINCPED Transfer Tank Vented Diesel Fuel Cap — 2" Threaded Neck, Lockable Spring-Loaded Vent

JYINCPED's Transfer Tank Vented Diesel Fuel Cap is a lockable, spring-loaded replacement cap with a 2-inch threaded neck that vents pressure and prevents vacuum collapse while sealing tightly to stop leaks.

This vented transfer tank cap replaces common 2" NPT threaded fuel bungs and is built for diesel and distillate tanks used on trucks, farm equipment, mobile fuel trailers and auxiliary tanks. It combines a cast-iron base with a removable, spring-loaded vented cap and an internal gasket to slow vapor escape, control internal pressure, and allow air to enter as fuel is dispensed. The cap accepts a small padlock for theft and tamper protection and is made from corrosion-resistant materials for extended field service.

How does this cap manage pressure inside a transfer tank?

The cap features a venting mechanism that allows built-up pressure to escape when loosening and lets air enter as you withdraw fuel, preventing dangerous over-expansion and vacuum collapse. The spring-loaded design and internal gasket coordinate to vent only when necessary while maintaining a tight seal under normal conditions.

• Both-direction venting: releases pressure outward and admits air inward
• Spring-loaded valve for controlled vent activation
• Internal gasket reduces unwanted vapor loss while sealing
• 2" NPT threaded neck fits standard transfer tank bungs

Will this cap prevent theft and tampering of diesel fuel?

Yes—there is a built-in lock tab that accommodates a 1/4"–5/16" shackle padlock (not included), letting you secure the cap to resist siphoning and unauthorized access. The tab sits on the base so a small padlock can immobilize the cap without special tools.

• Lock hole sized for common small padlocks
• Tab placement secures the cap to the base when locked
• Deters casual theft and tampering at work sites or while parked

How does installation and operation work on the 2-inch threaded neck?

Installation is straightforward: align the cap notch with the tank bung, push down and rotate clockwise until fully seated. To vent before full removal, turn counterclockwise slowly to the notch; push and twist to lift the vented cap and then remove safely.

• Fits standard 2" NPT transfer tank bungs and many Fill-Rite replacements
• Push-down and twist action for secure seating
• Slow counterclockwise twist vents pressure before full removal

What durability and leak-prevention features does it include?

Constructed from heavy-duty materials with a cast-iron base and corrosion-resistant cap parts, this assembly is made to withstand outdoor use and road vibration. A spring mechanism plus an internal sealing gasket minimize leakage and excess vapor loss even during transport.

• Cast-iron 2" base for rugged mounting and longevity
• Waterproof and corrosion-resistant components
• Gasket and spring-loading reduce leaks and vapor escape

Who is this for: This JYINCPED vented transfer tank cap is aimed at fleet operators, farmers, mobile fuel vendors, contractors and anyone who uses 2" threaded transfer or auxiliary fuel tanks. It’s a practical replacement for Fill-Rite-style caps when you need controlled venting, theft deterrence with a padlock option, and a durable seal that holds up to heavy use in the field.