Dorman 904-066 Diesel Exhaust Fluid (DEF) Filler Neck

DEF Filler Neck for Ford Super Duty

Dorman 904-066 is a diesel exhaust fluid (DEF) filler neck for select 2017-2019 Ford F-250 Super Duty and Ford F-350 Super Duty trucks. It matches the fit of the original neck when the factory part is leaking or has failed, helping maintain a secure transfer path from the fill point to the DEF tank.

• Direct replacement DEF filler neck for specified Ford Super Duty diesel applications
• Built with steel, plastic, and rubber materials for the intended OE-style construction
• Black finish for a factory-like appearance
• Bolt-on attachment method for the original mounting location
• Designed for reliable DEF transfer from the fill point to the tank
• Part number 904-066 for easy identification

Detailed Product Overview

This Dorman DEF filler neck is engineered for 2017-2019 Ford F-250 Super Duty and 2017-2019 Ford F-350 Super Duty models. It is a practical replacement when the original filler neck is cracked, leaking, or no longer sealing properly. The OE-style fit helps restore the DEF fill path on Ford Super Duty diesel trucks, and the black steel, plastic, and rubber construction supports the application’s original design.

Part number 904-066 also cross-references Ford HC3Z5J232D and HC3Z5J232H for the same application.

Common Problems This Part Can Address

• DEF leakage at the filler neck
• Cracked or damaged filler neck components
• Loose or unreliable DEF fill connection
• Difficulty transferring DEF from the fill point to the tank
• Replacement needs after the original neck fails on Ford F-250 Super Duty or Ford F-350 Super Duty trucks

Installation Notes and Tips

This filler neck uses a bolt-on attachment method and is intended for the original mounting location. Mounting hardware and cap are not included. Verify vehicle year, model, and OE part number before installation to confirm proper application on your Ford Super Duty diesel truck.

Quality Assurance

Dorman manufactures replacement emission control components to match original fit and function for specified vehicles. Dorman 904-066 is built as a direct-fit replacement for the listed Ford Super Duty applications.