When it comes to routine heavy-duty truck maintenance, the Urea/Diesel Exhaust Fluid (DEF) filter is rarely the first filter that comes to mind in need of replacement. 

Everyone knows oil, fuel and air filters must be changed periodically to maintain service intervals and engine warranties. Unfortunately, some parts managers and maintenance technicians may still be under the impression that Urea/DEF filters can outlast the life of a vehicle and overlook the need to replace them. 

One big reason why these filters can fly under the radar is because not every truck on the road has a Urea/DEF filter. In fact, it wasn’t until January 1, 2010, that all newly manufactured heavy-duty trucks were required to have selective catalytic reduction (SCR) systems, which require diesel exhaust fluid. 

Every time DEF needs to be refilled, dirt and debris can enter and compromise the system. On top of that, if the Urea/DEF filter isn’t replaced at recommended intervals, urea crystals and other contaminants can cause the SCR system to malfunction and create other problems that can affect the performance of a heavy-duty truck, including: 

Power Loss: Engine power can be reduced when a clog/ged filter restricts regular flow of DEF.

Pungent Diesel Odor: A Urea/DEF filter that has reached capacity can make it difficult for a truck’s SCR system to absorb nitrogen oxide and diesel particulate odors. 

Failing Passive & Active Regeneration: When Urea/DEF filters don’t allow for the free flow of clean DEF, it can also impact Diesel Particulate Filter regeneration performance. 

Increased Fuel Consumption: Not changing a Urea/DEF filter can restrict exhaust flow and increase back pressure, which makes it harder for the engine to breathe and operate efficiently. 

To avoid these issues, Urea/DEF filters must be replaced on an annual basis or every 120-150,000 miles. 

You can learn more about the relationship between heavy-duty performance and Urea/DEF filtration in the newest online training module at Luber-finer University. Register your free account to get started now at luberfiner.com/university. 

In addition to highlighting the problems of a clogged filter, this training module examines SCR technology, what can happen if DEF can’t reach a vehicle’s exhaust aftertreatment system and the coverage Luber-finer’s line of Urea/DEF filters provide. 

For more information on the Luber-finer line of Urea/DEF filters, visit luberfiner.com/products/urea-filters/.