DPF Cleaning

John Baxter | October 01, 2011

He adds that any shop should have testing capability as well. Without it, “it’s impossible for the technician to know how clean the filter is after cleaning.” FSX utilizes an airflow tester called the TrapTester7.

Maintenance for optimum DPF cleaning intervals

A DPF can work like a canary in a mine, says Myron Birschbach, vice president of aftermarket sales for Inland Power Group. “This form of aftertreatment can be a very good early warning device that can tell you you have an operating issue with an engine.”

Frequent clogging can warn of a problem with an injector, an air handling system or oil consumption. Such early notice could help reduce the cost of repairs and potential downtime.

The other side of the coin is that engine maintenance will pay larger dividends than in the past by extending DPF cleaning intervals. Proper maintenance includes:

• Regular oil changes to keep wear and oil consumption under control.

• Ideally, use of CJ-4 oil to extend the cleaning interval.

• Minimized idling. The resulting high oil consumption significantly increases ash accumulation.

Navistar’s Mark Ehlers says a static regeneration inhibition switch on vehicles with a power takeoff allows you to stop regeneration in certain conditions because so much heat is created during regeneration that it could risk fire or other damage, especially indoors. The risk is higher with horizontal DPFs. But don’t inhibit regeneration unless there’s a good reason.

On Internationals, one light advises to try to get the truck up to speed to clear out accumulated soot. Another advises to stop and do a parked regeneration. To understand what these mean, read the owner’s manual or visit the manufacturer’s website.

In parked regeneration, the engine raises the exhaust temperature. This does a better job of cleaning out soot than can occur under even favorable driving conditions. Following the directions is in large part about letting the unit regenerate itself as soon as indicated and as often as you can to decrease the chance the unit will need cleaning prematurely.

Ehlers says to watch for head gasket leaks that could allow coolant into the exhaust stream. Just five gallons could cover the platinum oxidation catalyst designed to accelerate regeneration, leaving the unit subject to frequent clogging. Clean the hydrocarbon injector as recommended to preserve the spray pattern.

And repair any exhaust leaks right away. Any loss of heat in the system inhibits the unit’s natural ability to burn off soot.

Volvo’s Ed Saxman warns against waiting too long to clean a Volvo DPF even though “there may not be a tremendous fall-off in performance. Cracks can form in the ceramic as a result of excessively frequent active regenerations,” which increase the temperature of the filter up to 1,100 degrees F.

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