DEF Contamination

Sept. 25, 2019

This bulletin discusses what will happen to the rubber material used in the urea pump when exposed to diesel fuel. 

This applies to 2013-later Ram trucks equipped with a diesel engine. This unit is sometimes referred to as the Selective Catalyst Reductant (SCR) module or the Adblue Delivery Module (ADM).

Units exposed to hydrocarbons have a particular failure mode. The rubber heater unit is crinkled and in some cases the metal heater protrudes through the rubber membrane.

The rubber material used in this unit is designed to withstand Diesel Exhaust Fluid (DEF) only. Exposure to fluids that contain hydrocarbons (diesel fuel) will damage the unit beyond repair.

Fluid at the urea pump can be tested for hydrocarbons with hydroscopic test paper P/N 223-44-863.  When testing with test paper, test the fluid at the top of the tank for the most accurate results.