The Relationship Between UREA/DEF Filtration & Heavy-Duty Performance

Urea/Diesel Exhaust Fluid (DEF) filters are a mission-critical filter that can influence the performance of a heavy-duty vehicle.

Often an overlooked part of truck maintenance, Urea/DEF filters are vital to:

keeping vehicles
in peak operating condition
fuel efficiency
The Origin of
the Urea/DEF Filter

The U.S. Environmental Protection Agency estimates that the transportation sector is responsible for 28% of greenhouse gas emissions. Of that 28%, 60% is caused by light-duty vehicles, while 23% is caused by medium- and heavy-duty trucks. To put it another way, medium- and heavy-duty vehicles represent only 5% of all vehicles on the road, yet account for more than 20% of transportation emissions.

To combat this problem, the EPA required all medium- and heavy-duty trucks manufactured on January 1, 2010 and after to meet emissions standards that reduce harmful carbon monoxide, hydrocarbons and particulate matter with an upgraded exhaust aftertreatment system.

How Your Customers — and the Planet — Benefit
from Proactive Urea/DEF Filter Maintenance.
A well-maintained truck means:

less maintenance

more money saved over the life of a heavy-duty vehicle

cleaner air for today and a better environment for tomorrow

But what makes the air cleaner?

The answer can be found in exhaust aftertreatment systems that combine the use of Diesel Exhaust Fluid, Selective Catalytic Reduction (SCR) technology and the application of a UREA/DEF filter.

Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that injects a liquid-reductant agent through a special catalyst into the exhaust stream of a diesel engine. The reductant source is usually a non-toxic, automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF).

A properly maintained SCR system means the engine runs efficiently and the SCR system operates as it should to significantly reduce emissions, thus promoting a cleaner, more environmentally-friendly future.


Diesel Exhaust Fluid (DEF) is a non-toxic solution of 67.5% water and 32.5% automotive grade urea and is one of the key elements of the SCR aftertreatment system. It can be purchased at many truck stops and retail locations either in jugs or from a dispenser at the pump.

Urea/DEF filters are an important line of defense for keeping DEF clear of debris that can cause performance issues. Unfortunately, not every service technician is aware that a Urea/DEF filter exists on newer truck models and that it needs to be replaced periodically.

How Does DEF Work in an SCR System?
(Click the Yellow Hot Spots for More Information)

What Happens if Your Customer Runs Out of DEF?

If trucks are allowed to run out of DEF, engine power will be reduced and vehicle speed will be limited to 5 mph until the DEF tank is refilled. Typical DEF consumption is about 2% of fuel consumed or

1 gallon
of DEF
50 Gallons
of Diesel Fuel Burned
Why UREA/DEF FIlters Are Important
To prevent a Urea/DEF filter from becoming clogged, it is important to
replace the Urea/DEF filter on an annual basis or
every 120,000-150,000 miles
A Urea/DEF filter that is not regularly replaced can become clogged by urea crystals and other contaminants that can cause the SCR system to malfunction. Some of the symptoms of a clogged filter include:
Replacing a Urea/DEF Filter Is Easy
All it takes is a few tools and a few minutes to remove an old Urea/DEF filter from the filter housing (located behind the onboard DEF storage tank) and install a new one.
The Luber-finer line of Urea/DEF filters offers maintenance managers and service providers a competitively priced alternative for some of the most popular trucks on the road today.
Luber-finer offers a range of Urea/DEF filters
for Cummins and non-Cummins engine applications for medium- and heavy-duty truck applications.

While Urea/DEF filters represent a smaller segment of the heavy duty filtration market, they are still critically important for maximizing equipment life and vehicle uptime. As such, it is vital for sales representatives to understand the key benefits and customer pain points connected with Urea/DEF filtration.

The fact that education on Urea/DEF filters is not as abundant as other types of filtration solutions provides an opportunity for sales personnel to further differentiate themselves and showcase their expertise. While it is likely that fleets will primarily be concerned with performance and costs associated with oil, fuel and air filters, making Urea/DEF filters part of the discussion can help tip the scales toward a Luber-finer conversion.