DPF Cleaning

John Baxter | October 01, 2011

He notes that intervals vary with oil type. “Our 2007 interval when running CI-4 oil is 200,000 miles, 22 months, or 4,500 hours, while with CJ-4 it is 250,000 miles, 30 months, 6,000 hours. The difference is that a lot of the ash was taken out of CJ-4.

Volvo Powertrain Marketing Manager Ed Saxman says his company recommends cleaning the DPF at 250,000 miles or 4,500 hours, whichever comes first. “The DPF is large enough that, with proper maintenance, there is not a significant performance difference between a new filter and a dirty filter,” he says, adding that you’re only likely to notice a difference “if the filter becomes full of ash.”

The recommended cleaning interval for Detroit Diesel engines is between 300,000 and 400,000 miles for most applications, notes Williamson. “The other way to determine this is to remove the filter and use the Detroit Diesel service tool to check the capacity.”

Where and how to clean

Owners “should thoroughly familiarize themselves with what the manufacturer of the DPF recommends among the many different cleaning methods,” Giguere says. “Cleaning methods include compressed air or heat or a combination of both. But, some filters may be sensitive to high temperature or pressure.”

This FSX machine is used by Navistar and Paccar Parts in cleaning DPFs.

One sure approach is taking advantage of a technology the manufacturer has developed. Giguere notes Detroit Diesel’s method of treating the interior surfaces with a liquid is “substantially different from the methods used by other manufacturers. By applying a liquid, Detroit feels they can clean the filter to a higher level.”

Cleaning is done at Detroit’s network of remanufacturing centers, which are outfitted to do liquid and air cleaning. Williamson recommends simply utilizing the reman exchange program to swap a dirty DPF for a newly cleaned one.

Detroit Diesel’s website reveals its DPF is constructed of a material designed to tolerate the water-based cleaning process. It also says that its reman units are covered by a one-year warranty with no limit on miles, and that the change interval for a DPF cleaned with their process has the same recommended service interval as a new one.

Volvo also encourages owner-operators to exchange with a factory-reman filter. “Cleaning a DPF involves more than just using an industrial vacuum cleaner to remove soot,” says Saxman. “Remanufactured filters customers receive through the Volvo exchange program have been ultrasonically inspected to detect any anomalies before undergoing our thorough cleaning process.”

Another reason to be aware of manufacturer recommendations: Maintaining your warranty. “If you have the unit cleaned using an unapproved method, it could alter your warranty,” says Pacific Power Products Emissions Business Unit Manager Gary Parsons.

In choosing a shop to do the work, says Parsons, look for a cleaning process “that is documented step by step. They should be keeping records that will verify that each step of the process was completed on each filter you send in for cleaning. There should be a check sheet.”

Ehlers stresses the value of a shop’s experience doing the job. “International partnered with FSX to develop its cleaning process. It gives by far the most thorough cleaning, from data I’ve seen. The filter is baked first for 4 to 24 hours, depending on the design, to loosen the carbon. It works like a self-cleaning oven, and this turns gooey stuff that is hard to clean off into a powder. We also have the ability to flow-test the unit after cleaning to make sure it has been thoroughly restored to original condition. Ask the facility whether or not, if the unit clogs after six months, they will stand behind it.”

Paccar also utilizes the FSX cleaning process, says White. “We recommend the use of a machine that employs a visual cleaning process over one that uses a pulse cleaning process. Pulse cleaning assumes that all cells are plugged equally and results in inconsistent and incomplete cleaning. A DPF’s outside cells tend to gather more ash buildup than the cells near the center of the filter.”