Dorman 904-387 Diesel Exhaust Fluid (DEF) Heater

Dorman 904-387 DEF Heater for GM Diesel Vans

Dorman 904-387 is a specific-fit Diesel Exhaust Fluid (DEF) heater for select Chevrolet Express and GMC Savana diesel applications. It addresses a common factory failure point caused by fluid intrusion and updates the OEM design to improve heater reliability.

• Specific-fit DEF heater for select GM diesel vans
• OE FIX design addresses fluid intrusion at the original heater design
• Black plastic housing and black hose components
• Male/female electrical connector design with 2 connector quantities listed
• Includes mounting hardware and a coupler
• Level sensor type: resistor
• Inlet fitting type: male; outlet fitting type: female

Detailed Product Overview

This Dorman DEF heater is built for diesel exhaust fluid system service on 2012-2016 Chevrolet Express 2500, 2012-2016 Chevrolet Express 3500, 2012-2016 GMC Savana 2500, and 2012-2016 GMC Savana 3500. The part number 904-387 is engineered as an OE-style replacement that modifies the factory layout to reduce the failure mode associated with fluid intrusion. For technicians and owners servicing Chevrolet Express and GMC Savana diesel vans, 904-387 provides a direct-fit solution for restoring DEF heater function without changing the vehicle’s original application requirements.

Construction details include a black plastic housing, plastic hose materials, and a resistor-style level sensor. The unit uses male and female electrical connector interfaces and is supplied with a coupler for the specified application. Cross-reference part numbers for the same application include Standard Ignition DFH107 and 22905128.

What It Helps Fix

• DEF heater failure caused by fluid intrusion into the factory design
• Loss of DEF heating performance in cold-weather operation
• DEF system faults related to heater circuit issues
• Service interruptions on Chevrolet Express and GMC Savana diesel vans
• Replacement needs for worn or damaged OE heater assemblies

Installation Notes and Tips

Verify vehicle year, make, model, and DEF system configuration before installation. This part is a specific-fit component for 2012-2016 Chevrolet Express 2500, Chevrolet Express 3500, GMC Savana 2500, and GMC Savana 3500 applications. Confirm connector style, inlet and outlet orientation, and mounting points against the original unit before final assembly. Use the included coupler as required by the application and inspect surrounding DEF lines and electrical connections for contamination or damage during service.

Quality Assurance

Dorman OE FIX parts are built to address known failure points in original equipment designs. Part number 904-387 follows that approach by revising the factory DEF heater design for improved reliability in the listed GM diesel van applications.