DICMIC Diesel Transfer Tank Vented Cap 2-inch Threaded Base, Cast-Iron Pressure-Relief Vent

The DICMIC Transfer Tank Vented Cap is a 2-inch threaded, pressure-relief fuel cap that vents vapors and prevents vacuum collapse for diesel transfer and storage tanks.

Built for rugged use on transfer tanks and auxiliary fuel containers, this venting cap assembly combines a removable vented cap with a heavy-duty cast-iron 2-inch threaded base. The design channels trapped pressure and allows air to enter as fuel is dispensed, reducing stress on tank walls and minimizing vapor build-up while resisting water and corrosion for long-term performance.

How does this cap control pressure and vapors in a diesel tank?

When the cap is loosened to the vent notch, internal tank pressure is released safely to the atmosphere, helping prevent over-expansion from trapped vapors. The vent also lets ambient air back into the tank as fuel is drawn out, avoiding negative pressure that can deform the container.

• Removable vented cap vents excess pressure when rotated to the notch.
• Vent path reduces dangerous vapor accumulation in enclosed tanks.
• Allows controlled air intake to prevent vacuum formation during pumping.

What materials and features make it durable?

The cap assembly uses corrosion-resistant components and a waterproof construction to withstand outdoor exposure and contact with diesel and distillates. The cast-iron 2-inch base provides secure mounting and a stable threaded seal that holds up in farm, commercial, and mobile fuel applications.

• Waterproof and corrosion-resistant materials for long service life.
• Heavy-duty cast-iron 2" threaded base for robust mounting.
• Removable top cap for easy cleaning or replacement if needed.

Is it simple to install and operate on existing tanks?

Yes — the cap installs without special tools: align the vent cap with the base notch, push down, and twist clockwise until fully seated. To open, twist counter-clockwise to the notch to vent first, then push and lift to remove, making operation safe and straightforward for routine fueling tasks.

• Tool-free installation: align, press down, and twist to secure.
• Two-step removal (vent then lift) for controlled depressurization.
• Designed for retrofit to common 2" threaded transfer and auxiliary tank openings.

Which tanks and applications is this cap compatible with?

This vented cap is intended for transfer tanks, mobile fuel tanks, auxiliary and weather-protected tanks used in agricultural, commercial, and industrial settings. It fits many diesel, distillate, and fuel storage applications where a 2-inch threaded base is standard.

• Compatible with transfer tanks, fuel tanks, auxiliary/mobile fuel containers.
• Suitable for farm equipment, service trucks, and on-site refueling systems.
• Works with tanks designed for diesel and similar distillate fuels.

Who is this for: The DICMIC Transfer Tank Vented Cap is aimed at fleet managers, farmers, contractors, and anyone who maintains mobile or stationary diesel storage and wants a durable, easy-to-use venting solution. It’s a practical upgrade for older tanks prone to vapor buildup or vacuum collapse and a reliable replacement part for routine maintenance.