Dorman 904-5401 Diesel Exhaust Fluid (DEF) Filler Cap

DEF Filler Cap for Specific Vehicles

The Dorman 904-5401 diesel exhaust fluid (DEF) filler cap is a specific-fit replacement for the original cap used on selected vehicles. It is built from plastic with a blue housing color and is designed to match the fit and function of the OE part for reliable sealing at the DEF fill point.

Use this Dorman DEF filler cap when servicing diesel exhaust fluid systems on vehicles that require a direct replacement cap. The part number 904-5401 is also referenced for cross-checking during catalog lookup and parts verification.

Key Features

• Direct replacement DEF filler cap for specific applications
• Plastic construction for everyday service use
• Blue housing color for easy identification at the fill location
• Engineered to match original fit and function
• Retention ring listed in package contents
• Specific fit design for selected vehicle applications

Detailed Description

Dorman 904-5401 is a diesel exhaust fluid filler cap made to replace the original cap on specified vehicles without changing the factory-style fit. It is intended for diesel emission control service where a secure DEF fill cap is needed to help maintain the system’s normal sealing and access point. This part cross-references Monroe Shocks & Struts (e.g., 572.3005, 908022301) for the same application. For buyers searching DEF filler cap replacement for Ford F-250, Ford F-350, or Ford Super Duty service needs, this part number can help narrow the correct OE-style match.

What It Helps Address

• Broken or missing DEF filler cap
• Worn cap that no longer seats properly
• DEF fill opening exposed to dirt and moisture
• Need for a direct-fit replacement during emission system service
• Identification issues when replacing a blue DEF cap on diesel vehicles

Installation Notes and Tips

Confirm the vehicle uses the correct DEF filler cap style before installation. Compare the original cap shape, retention features, and fill opening design to Dorman 904-5401. For fitment-based searches, use phrases such as DEF filler cap for specific diesel applications, direct replacement DEF cap, and OE-style DEF cap replacement for Ford Super Duty trucks. If the original retention ring is damaged or missing, inspect the fill neck and surrounding components before installing the new cap.

Quality Assurance

Dorman designs this cap to match original fit and function and builds it for durable, reliable performance in diesel exhaust fluid service.