The Cleaning Crew

TransAm Trucking opens the 'Pandora's Box' of DPF cleaning


The diesel particulate filter (DPF) clock has been ticking for more than two years now. Fleets that bought trucks with EPA 2007 engines will be reaching their maximum 250,000 mile service intervals soon and need to be removed from their trucks and cleaned.

"I think this has missed a lot of people," says Frank Nicholson, director of maintenance at Olathe, KS-based TransAm Trucking.

"The dealer that we have, MHC, which is one of the largest PACCAR dealers in the nation, they weren't even thinking about it until we started pushing on it," he says. "And it took me a while to think about it, so I think that the industry as a whole is just dealing with the everyday fires and I think this is just going to be Pandora's Box when it starts hitting hard and heavy.

"Due to the fact that we have so many of these DPF-equipped units on the road, I have done my share of due diligence on the subject, and see some disturbing problems."

Where are the DPF cleaners?

Disturbing is putting it lightly. TransAm bought 300 2007 trucks, and when some of them started coming due for their first-ever DPF cleaning, Nicholson immediately started running into trouble.

"We're finding that, across the country as a whole, there are not but a handful of dealers that have any idea what they're doing," he says. "And I'm speaking specifically about our specific fleet, meaning a PACCAR product with a yellow engine.

"Not every one of the distributors is going to have one of these machines, so you're stuck trying to get it cleaned only where there is one," Nicholson goes on. "And a distributor's hours may be different from a dealer, which is 24/7. So you've got to wait until that place is open to get your DPF cleaned.

"And, the knowledge (of DPFs) across the country is very, very limited; it's not as simple as rolling in, pulling the unit off, sticking it on the machine and getting it cleaned, at least not with Caterpillar."

On the contrary, Nicholson explains: when a truck is taken in for a DPF cleaning, it must first go through an active or a forced regeneration, to burn off the material in the DPF. Only then can the filter element be taken off the truck and placed in the machine for cleaning. After it's cleaned, the DPF's flow rate must be tested to make sure it matches the manufacturer's setting. If it passes, it can be reinstalled and the truck can be on its way.

But here's the catch: the truck's computer has to be reset to show that the DPF has been cleaned. "If somebody doesn't reset that and you put the DPF back on then it's done you no good," Nicholson explains. "And we know that, because the ones we've cleaned, the dealers didn't know that it had to be reset. We were actually checking them, following them, tracking them, and the fuel economy didn't get any better, and I thought,

'What the heck?' Well, after we got to digging into it, we realized that our engine manufacturer said, 'Oh yeah, by the way, this is what you've got to do.' Not even everybody at the engine manufacturer knew! We went back and got them reset, and now the fuel economy's starting to gain on these units."

Thermal Events

You may be wondering what exactly happens when a DPF reaches the ripe old age of 250,000 miles. Frank Nicholson can tell you.

"We sat through those cleaning presentations, and one vendor in particular said that while most fleets are concerned about fuel economy degradation, what they don't realize is that the farther you run these DPFs without cleaning them, (the more) you're going to start to deteriorate the DPF itself," he says. "Then you take a chance that, when you reach a point where you can't drive the vehicle anymore and you go to clean it, it's not cleanable. Not necessarily because they can't get it out, but it's had so many 'thermal events' inside the DPF that it basically breaks down the inside of the DPF and you have to replace the whole thing.

"Now you're looking at several thousand dollars to replace the DPF instead of several hundred dollars (maybe a thousand, depending on who you go to) for the cleaning."

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