Diesel Exhaust Fluid (DEF) Storage and Handling

Our mission at Managed Mobile is Safe, Compliant and Reliable Fleets.

Diesel Exhaust Fluid, or DEF, is essential to the reliable operation of trucks equipped with SCR exhaust after-treatment systems. Virtually all diesel engines manufactured after 2010 are equipped with this emissions technology and require regular top off / filling of the DEF tank.

We recently encountered maintenance issues due to contaminated DEF fluid added by our customers to their trucks. The cause of the contamination in these incidents was outdoor storage without insulation, or, improper storage and pump equipment being used. The result was expensive damage to components as well as downtime for the vehicles.

Please be aware of the following for the proper storage and handling of DEF fluid:

1. DEF, whether in bulk containers or gallon jugs, should not be stored outdoors where it is exposed to temperatures that exceed 86 degrees Fahrenheit.  This affects the product integrity and we’ve seen the fluid start to crystalize and break down. Compromised DEF fluid integrity is detected by the truck ECM and can result in engine deration, shut down, and other exhaust after-treatment component issues.

2. DEF should only be stored and pumped from either suitable stainless steel or plastic equipment. We’ve seen rust contamination when a steel down tube from a pump was used in a bulk container. Over time, the bottom of the steel down tube began to rust and the contamination was being pumped, unknowingly, into the DEF tanks on their trucks. This resulted in the clogging of dosers and other components in the SCR system.

If you currently have DEF fluid on premise for your drivers to top their trucks, please make sure to follow these best practices.