DEF Non-Locking Cap Assembly | 10051899

The DEF Non-Locking Cap Assembly 10051899 is a high-quality aftermarket replacement designed to maintain Diesel Exhaust Fluid (DEF) system integrity in heavy-duty vehicles. Compatible with a range of OEM applications, this cap features a secure screw-tab closure and an integrated lanyard for easy handling and retention during service. Built to meet or exceed OEM specifications, it ensures a tight, leak-proof seal to protect against dirt, moisture, and DEF crystallization.

Manufactured from DEF-safe, chemical-resistant polymer, this cap is engineered for long-term durability in demanding operating environments. The non-locking design provides quick, tool-free access to the DEF tank without compromising system pressure or emission control reliability.

Ideal for fleet operators, service centers, and owner-operators, the 10051899 cap supports efficient maintenance while reducing the risk of DEF system failures. It’s a direct-fit solution that restores DEF tank function and protects your SCR system investment.

Backed by a full manufacturer warranty and available with fast shipping, this DEF cap assembly delivers trusted performance, easy installation, and long-term reliability. Replace your worn or missing DEF cap with this dependable aftermarket part to keep your vehicle compliant, clean, and running smoothly.