17How to Determine if the DPF or DOC is Viable Tech Tip

TECH Tips CATALOG NUMBER 17 www.midwestwheel.com Order NLINE ™ www.midwestwheel.com Order NLINE ™ How to Determine if the DPF or DOC is Viable 1) Visual Inspection: DPF Inlet (the Dirty & Engine Side) ▪ The inlet will look blackened across the total face of the filter, which is normal (See 1st image) ▪ However, there shouldn’t be any excessive soot such to the degree of DPF face plugging or heavy accumulation of soot (See 2nd and 3rd image). This would signal likely upstream engine and/or DOC issues that require investigation. The inlet should be free of cracks/damage. DPF Outlet (the Clean Side) ▪ An u ndamaged DPF should look almost brand new like the day it was installed and off-white to beige in color with no signs of any cracks or soot by-pass (see figure 1). ▪ Evid ence of significant soot by-pass with the soot-staining on the outlet side is confirmation that the DPF is breached/cracked and needs to be replaced and should not be sent out for cleaning. » Figure 2 shows significant soot by-pass = failed DPF » Figure 3 shows blown cells (small back dot on the outlet) and still viable provided less than 20 cells, however, multiple cells in one area (size > dime/nickel) = failed DPF » Figure 4 and 5 show signs of staining by coolant or oil which signifies upstream issues and = failed DPF when combined with black soot staining » Figure 6 shows cross-sectional cracks evident by soot staining around the outer diameter » Figure 7 shows DPF substrate melting and uncontrolled regeneration with likely upstream engine and/or DOC issues and = failed DPF 2) Pin-Gauge Testing A pin-gauge test is an inexpensive and useful tool to help determine and measure how dirty the DPF is via the inlet side. By inspecting the outlet side, you can get feel for how an unobstructed channel should track with the pin- gauge and possibly confirm any internal DPF flaw and/or cracks if the rod path is obstructed via the outlet side. Pin-gauge specs: Approx. 0.032 to 0.034” diameter stainless steel wire/rod x ~24” long. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7