Aluminum Locking Diesel Fuel Cap, 3.00 Inch Diameter (Part Number FC0183-6) by Cleveland Tank. Heavy-duty locking fuel cap machined from lightweight, corrosion-resistant aluminum to resist leaks, cracks, and fuel contamination. Features a 3.00-inch nominal diameter with female threads at 8 threads per inch (8 TPI), a non-vented design, and a built-in locking mechanism to help deter fuel theft and tampering. Weighs 1.0 lb with overall dimensions of 3.0 x 3.0 x 2.0 inches. Designed as a direct-fit replacement diesel fuel tank cap for fuel systems requiring a 3.00-inch female-thread, 8 TPI fitting. Suited for fleet, vocational, and commercial truck fuel tank applications where a secure, weather-tight, anti-corrosion locking fuel cap is needed.

The FC01683 from Cleveland Tank is a 2.00-inch diesel fuel cap sized for smaller fuel system openings than Cleveland Tank’s standard 3- and 4-inch caps. It has a female thread design at 11.25 threads per inch (11.25 TPI) — a finer pitch than the 8 TPI spec used on the larger caps in the line — so getting the thread count right matters for a proper seal. Machined from lightweight, corrosion-resistant aluminum, it resists the rust and pitting that shorten the life of a steel cap. This is a non-locking, non-vented cap, built for diesel fuel systems that don’t require a keyed lock. At 1.0 lb and 2.0 x 2.0 x 2.0 inches, the FC01683 is a direct-fit replacement for diesel fuel tanks specifying a 2.00-inch, 11.25 TPI female-thread cap.

The FC1012 from Cleveland Tank is a brass locking diesel fuel cap, built from a heavier, more rigid material than Cleveland Tank’s standard aluminum caps for applications where extra durability matters. It has a 2.00-inch diameter and female threads at 11.5 threads per inch (11.5 TPI), and it’s both locking and vented — the integrated lock secures the tank against theft and tampering while the vented design lets the tank equalize pressure properly as fuel is drawn down. Two keys ship with every cap. At 1.0 lb and 2.0 x 2.0 x 2.0 inches, the FC1012 is a direct-fit replacement for diesel fuel systems specifying a 2.00-inch, 11.5 TPI brass locking vented cap.