HOW WE INSPECT, TEST, AND DECISION FILTERS

Sean (owner) cleaning a filter in the blast cabinet.

 

Welcome to Aftermarket DPF, a premier diesel engine aftertreatment system cleaning company. We specialize in cleaning diesel particulate filters (DPFs), diesel oxidation catalysts (DOCs), and selective catalytic reduction filters (SCRs), which are essential components in modern diesel engines that help reduce harmful emissions. Our team of experts takes pride in delivering top-notch services that help optimize your engine's performance while reducing your operational costs.

At Aftermarket DPF, we believe in providing our clients with tailored solutions that meet their unique needs. That's why we put every filter through a rigorous multi-point inspection to determine its overall condition accurately. We use a "rule of two" method that eliminates potential false failures due to factors like insulation pass-through or cross-sectional surface cracking.

 

We Perform The Following Tests On All Cleanings:

  • Part Visual Inspection
  • DPF Restriction Test
  • Filter Weight Reduction Test
  • Leak Smoke Test
  • Segmentation Light Test*
  • Internal Pin Test



*Failed Light Test Example

 

When internal cracking occurs, light can be seen through the filter.

 

Once we complete the initial inspection, we grade the filter using a Green/Pass, Yellow/Caution, and Red/Fail scale determined by several characteristics observed during the inspection. We believe this process helps us offer our clients accurate results and ensures that they receive the best services possible.

 DPF / DOC / SCR Cleaning Stages

Stage 1 - 4 Cleaning Selection Chart

 

Finally, it's essential to note that the ultimate decision on what to do with a filter will rest with the client. We merely provide our findings and recommendations and advise our clients on the best course of action. At Aftermarket DPF, we aim to deliver the best customer experience possible, which is why we prioritize our clients' needs and satisfaction above everything else.

Thank you for considering Aftermarket DPF for your diesel engine aftertreatment system cleaning needs. We look forward to serving you!
 

 Dirty one box DPF with technican making line on the dirty side of the filter with a gloved finger. Dirty one box DPF with technican playing tic tac toe on the dirty side.
 Who said work can't be fun?

 

 

SIGNS OF FILTER CONTAMINATION

Ignoring filter contamination can result in expensive damage to your aftertreatment system. This section offers guidance on identifying and repairing contamination in your aftertreatment system caused by oil, fuel, or coolant. You will learn about potential causes of contamination and how to remedy the issue.

 

Oil Contamination

 

Bobcat oil soaked filter Hino oil soaked filter Closeup of the oil draining from filter.
(Pictures in order: DOC Outlet; Oil Draining From Soaked Filter; Closeup of Oil)

 Indications:

  • Blue smoke emitting from the exhaust pipe. This occurs when oil is burned through the aftertreatment system.

Causes:

  • Failure of internal engine block leading to cylinder compression and piston ring issues
  • Failure of internal engine cylinder head including valve seals, stems, and guides
  • Cylinder head gasket failure
  • Failure of oil cooler
  • Failure of Oil Cooled EGR Valve
  • Failure of internal VGT Turbo (Oil Cooled)
  • Any component that causes oil to enter the exhaust system

To determine the cause of oil contamination, inspect the system thoroughly:

  • Check for oil smell
  • Check for oil loss
  • Look for excessive blue smoke emission
  • Look for fault codes related to oil pressure, oil loss, or related systems

         

        Fuel Contamination

         

        Fuel contaminated filter; DOC inlet. Fuel contaminated filter; DOC outlet. Fuel contaminated filter; DPF inlet.
        (Pictures in order: DOC Inlet; DOC Outlet; DPF inlet)

        Indications:

        • White or black smoke emitting from the exhaust pipe. This occurs when the diesel fuel is not being burned correctly or raw fuel is entering the system.

        Causes:

        • 7th Injector is stuck open.
        • Leaking fuel injector.
        • Misfiring cylinder.
        • Over fueling is occurring.
        • Potentially any component that causes fuel to enter the system.

        To determine the cause of fuel contamination, inspect the system thoroughly:

        • Check for visible signs of fuel leakage.
        • Identify excessive white smoke or black smoke out of exhaust pipe.
        • Check to see if you smell the location of the fuel leak.
        • Check fault codes to determine if any active codes are related to the aftertreatment fuel injector or shut off valve.

         

        Coolant Contamination

         

        Coolant contaminated filter; DOC outlet. Coolant contaminated filter; DPF inlet. Coolant contaminated filter; SCR inlet.
        Pictures in order: DOC Inlet; DPF Inlet; SCR inlet

        Indications:

        • White smoke emitting from the exhaust pipe. This occurs when various failures occur that are caused by coolant entering the system.

        Causes:

        • Internal failure: Engine Block.
        • Gasket failure: Cylinder Head.
        • Part failure: EGR Cooler (Cooled by Coolant).
        • Part failure: EGR Valve (Cooled by Coolant).
        • Part failure: Internal VGT Turbo (Cooled by Coolant).
        • Potentially any component that causes coolant to enter the system.

        To determine the cause of fuel contamination, inspect the system thoroughly:

        • Check for signs of coolant odor.
        • Check coolant level to determine if losing fluid.
        • Identify excessive white smoke.
        • Check fault codes to determine if any active codes are related to the coolant or related components/system.

            HOW TO CLEAN A CONTAMINATED AFTERTREATMENT SYSTEM

             

            Once the source of oil, fuel, or coolant contamination is identified in an aftertreatment system, it's time to take action.

              • Step 1 - Remove your Aftertreatment System
                  • Start by removing and inspecting the Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), and Selective Catalyst Reduction (SCR) filters for signs of face cracking or burn-through due to overheating of the DPF.
                Sean (owner) working on removing aftertreatment system components. Sean (owner) working on removing a heat shield to access the aftertreatment components.
                Isuzu aftertreatment system with filters removed for cleaning.
                  • If horizontal or vertical cracking or melting occur, then a full replacement of the DOC, DPF and SCR filter system is in order. Possible surface cracking can occur that may not continue throughout resulting in a yellow tagged filter. Additional testing is performed to determine if internal melting or cracking has occurred.*
                *Yellow tagged filters show signs of wear and potential signs of failure. In the event your filter is tagged yellow, please consult with your cleaner on your options.

                 

                  • Step 2 - Cleaning your DOC / DPF / SCR filter(s)
                    • The most common method for this is baking, which uses heat to burn away soot from the filter. For a more thorough deep clean, you can use a blast cabinet with compressed air and vacuum technology, LIKE US!
                    Inside picture of open kiln. Inside picture of kiln while it is firing at 1112 degrees.
                    Olympic kiln firing at 1112 degrees F

                     

                      • DIY methods like water pressure washing can appear to also be an option, though the risk of damaging the filter is high and should be avoided unless you are experienced. If you decide to go this route, then the filter should be left to dry for at least 10 hours prior to re-installation.
                        • Step 3 - Clean All Other Aftertreatment Components
                          • After all contaminants (oil, fuel and coolant) have been cleaned out of the system, disinfect exhaust system piping post-turbocharger up until where it reaches the DOC filter.
                          • Clean all temp and pressure sensors with electrical cleaner and make sure NOx PPM sensor readings are valid for optimal DPF/SCR performance; NOx sensors might need replacement due to contamination.
                            • Step 4 - Perform a Forced Regen
                              • Start the engine and let it run (at Idle or High Idle) for 1 to 3 hours without producing any smoke. During this time, remember to park your vehicle outside in order to allow exhaust gases and possible smoke bills to diffuse into the atmosphere.
                              • Confirm that the regeneration system functions correctly. You'll need an advanced diagnostic tool at this stage. If fault codes remain active during the DPF regen process, identify them and replace failed parts before beginning again. In certain cases, two consecutive regens may be recommended to attain optimal temperatures against contamination.

                             

                            Truck driving down the road at sunset w/ Aftermarket DPF company information.

                             

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