Diesel engines operate similarly in many ways to traditional gasoline engines, using internal combustion to propel the vehicle forward. However, there are a few major differences between the two that are important for any diesel vehicle owner to understand. These unique engines also require unique maintenance services, such as the replacement of diesel exhaust fluid.
In this article, we’ll cover what diesel exhaust fluid is, why it’s needed in modern diesel vehicles, and how often you should consider replacing yours.
What Is Diesel Exhaust Fluid?
Diesel exhaust fluid, or DEF, is a fluid required for emissions control in all modern diesel powertrains. As diesel combusts, it releases toxic nitrogen oxide fumes that need to be converted into less-harmful compounds prior to exiting the exhaust system.
The selective catalytic reduction (SCR) system contains this urea-based fluid and injects it into the exhaust stream, which breaks down into ammonia and converts these exhaust fumes into harmless water and nitrogen.
Since 2010, the EPA has mandated the inclusion of an SCR system and DEF in all newly produced diesels, meaning any diesel vehicle produced past that point will likely require DEF replacement.
Why Does DEF Need Replacing?
Unlike other automotive fluids, which are cycled through the system continually, DEF is used up over time as it’s injected into the exhaust system. While only small amounts are used at a time, the DEF reservoir will eventually run dry if not topped off.
When modern diesels run out of DEF, it’s likely you’ll encounter a limp mode condition, meaning your engine will operate at an extremely limited level until your DEF reservoir has been refilled. Limp modes are designed to produce just enough power to get you to a local shop without damaging your emissions system.
How Often Should I Replace My Diesel Exhaust Fluid?
A typical 5-gallon DEF reservoir will generally last between 5,000-7,000 miles, as DEF usage is often equal to around 2%-3% of diesel usage. Of course, the exact lifespan and usage depends on a variety of factors, including the make/model as well as driving habits. Heavy towing or spirited driving can cause the rate of DEF usage to increase significantly.
It’s important to note that DEF has a usual shelf-life of around 12 months, which means even if you aren’t driving your diesel vehicle enough to drain the reservoir, you’ll still need to have the fluid replaced before the one-year mark.
Diesel & Emissions System Maintenance in Spicewood, Texas
If you drive a light truck or other vehicle with a diesel powertrain, trust the experienced team at Vineyard Bay in Spicewood, Texas to provide you with the utmost quality of service and repair. No matter the issue you’re facing, from emissions problems to powertrain failures, our technicians have the equipment and training to ensure you can always have peace of mind in the service you receive from our facility.
Give us a call or schedule online today to secure your appointment with the premier diesel care and repair destination in the Spicewood area!