Preventative Maintenance: How to save your money and your engine

Is the NOX deficiency light coming on? Or maybe your big rig continuously goes into limp mode. Neither of these are good as it is critical that we keep trucks on the road rolling. There are many reasons your engine might be needing attention but one of them could be the Selective Catalytic Reduction (SCR) catalyst. The SCR catalyst is designed to take in NOx (nitrogen oxides) with the use of DEF and convert it to water vapor and nitrogen gas. When the SCR gets plugged up with crystalized DEF or other contaminates it will cause some of these warning signs and it is time for cleaning.


Most trucking and transportation companies know when to clean their SCR but if not here are some things to watch out for:

  • Your truck goes into limp mode
  • Warning lights or check engine lights flashing


Preventative maintenance is cheaper and lasts longer than buying new filters. To keep your SCR running smoothly, it needs to have a sufficient supply of Diesel Exhaust Fluid (DEF). The catalyst must have enough DEF, or it is at risk of being ruined.


What is EGR cleaning?

The EGR is an Exhaust Gas Recirculation is a within diesel engines to reduce the release of nitrogen oxides. It works with a cooling double walled cooling chamber and a EGR valve to pump exhaust gas with high NOx levels back into the engine to combust and lower the flame temperature in the cylinder. If it is clogged, the exhaust won’t be able to travel back into the engine causing back pressure. The calve can either get stuck open or closed as well. If the valve gets stuck open, it can allow a continuous flow of gasses into the engine which will interrupt the combustion process. If the valve gets stuck closed, the fuel ignites before combustion. The test & clean process involves high pressure air as well as soaking the filter. In addition, we do our kilning process as well. We can clean all types of EGR systems.


What is SCR Cleaning?

Selective Catalytic Reduction is used to reduce diesel engine emissions. When the SCR becomes too plugged up, warning lights could appear on your dashboard. Your truck may lose power or not accelerate like it used to. Our technicians firstly blow out the filter to remove any lose debris. The flush and kiln process thoroughly cleans out any crystalized DEF or other detritus.


How does the SCR work to reduce NOx?

The DEF fluid is sprayed through the SCR to react with the particulate matter in the filter. It needs to be mixed thoroughly with the exhaust gasses to achieve high NOx to nitrogen conversion. Ammonia in the catalyst is a reactant that allows cleaner exhaust to come out of the tail pipe. This is known as reduction, so the DEF reacts with the NOx to convert the pollutants into water, nitrogen and small particles of CO2. SCR systems can reduce the NOx emissions from 50-90%, depending on the filter.



Transporting goods across the country isn’t cheap, and at The DPF Company we will do everything we can to keep your diesel engine in working order. Investing in preventative maintenance is the best way to keep a minor issue from becoming a major problem.