Will '07 Engines Cause More Headaches for Your Techs?

Cleaning the DPF will require a specialized tool. "They are mostly air pulsing machines," says Dutko. The DPF is removed and placed in the air pulsing tool for approximately 15 minutes. The air pulses then loosen the ash so it can be removed. This takes roughly 30 minutes. So the whole process can be done during a normal PM.

"The design target for cleaning is 30 minutes or less, not including removal and installation time from the vehicle," says Nigh. "Cummins will allow filters to be exchanged between vehicles, or customers may choose to use a recon exchange. The particulate filter is the only component of the Cummins Particulate Filter system that will require service."

The cost of DPF cleaning tools, coupled with the infrequent demand for cleaning, means most customers will not be able to justify the purchase of these tools. "They are all in about that same $10,000 to $12,000 range," says Dutko. This will leave the cleaning to the dealer network.

Mack has also addressed this issue by offering a DPF exchange program. "We anticipate initially the core exchange program through Re-Mack will be the common path until economies of scale dictate local cleaning and repair," says McKenna.

Handling of the ash after it is removed from the DPF depends on your location. "Every repair shop will have to consult its local ordinances to determine if the ash is considered hazardous material and how it should be handled," says Ashburn. "There are no federal guidelines. Some states do have guidelines."

Crankcase ventilation changes

"Crankcase gases will be included in emission measurements for the first time in 2007 engines," says Nigh. This has led to crankcase ventilation systems that prevent oil residue associated with engine blowby gas from escaping.

There are a couple of different approaches being used: closed crankcase ventilation and high-efficiency ventilation systems with coalescing filters. "Caterpillar will be using open crankcase ventilation on our heavy-duty C15 and C13 engines, and closed crankcase ventilation on our medium-range C9 and C7 engines," says Ashburn.

The engines with open crankcase ventilation will be fitted with filters. "The filter on the C15 and C13 will need to be replaced every third oil change (90,000 miles)," says Ashburn.

"The coalescing filter system, made by Cummins Filtration, will offer the additional benefit of eliminating oil drips," adds Nigh. "A simple, low-cost filter replacement is required every fourth or fifth oil drain."

Access to the engine has not been hampered by the new ventilation plumbing. "The piping required for these systems has not made access to other components any more difficult," says Ashburn.

And these systems keep the oil where it is needed. "The oil separator is taking the oil out of the combustion stream and running it back to the oil pan," says Dutko.

In some cases, this has positive benefits. For instance, the '04 Detroit Diesel Series 60 had a normal oil consumption rate of a quart every 3,000 miles. "Now it is a quart every 10,000 miles," says Dutko. "You use much less oil in the '07 engines." And the closed-crankcase system is maintenance free.

Mack's crankcase ventilation system incorporates a coalescing filter. "The coalescing filter is a maintenance-free device," says McKenna.

Oil and fuel usage restricted

"Another major issue will be use of the correct fuel and oil," says Ashburn. "Fifteen parts per million ultra-low-sulfur diesel fuel is required (by most manufacturers) along with CJ-4 oil. (See article on page 48.) The primary reason is because of the low ash formulation of the oil. It is the ash from the oil that fills the diesel particulate filter."

In a few cases, CI-4 oil may be acceptable. "With Cummins 2007 engines, customers will be able to use either CJ-4 or the current CI-4 oil," says Nigh. "The performance and durability of Cummins 2007 engines is assured with both oils." But use of CJ-4 oils assures that customers will see no change in maintenance.

The higher ash of the CI-4 oils could lead to the DPF plugging more rapidly. "The new oil (CJ-4) has 1% ash, or less," says Dutko. "Current oils that are used today are about 1.3% ash. So there is 30% more ash in today's oils. If you don't use the low-ash oil, the service interval for your filter will increase by about 30%."