@Dept:
It's a Slippery Situation
We've seen some pretty convincing evidence that the new standard results in better wear protection.
Steve Sturgess
Executive Editor
An announcement from Citgo that it's going to split its Citgard 700 line into two lines of engine oil illustrates the fact that many major lubricant suppliers are hedging their bets on the adoption of CJ-4 to go along with the '07 engines.
To back up for a moment, the oil formulators were required to come up with a category that would best support the aftertreatment devices for '07 engines – specifically the diesel particulate filter. The filter sifts out particulate matter, or carbon, from the combustion process in the engine. Then, through a couple of catalyst-enhanced reactions, the DPF turns the trapped carbon into carbon dioxide and blows it out the stack. This way, the particulate matter in the exhaust is cut to the mandated levels, and the trap regenerates itself on an ongoing basis.
But the DPF remains a tightly restricted trap that catches not just the regeneratable carbon, but also anything else in the exhaust that results from the combustion process. For the most part, this means ash from additives in the oil. This is why the filter needs occasional maintenance – cleaning out the trapped ash.
Hence the CJ-4 oil category. Its major contribution – aside from some great anti-wear advances – is that it produces very little ash to collect in the filter, stretching the service interval to at least 150,000-200,000 miles for over-the-road applications.
On the face of it, switching to CJ-4 when you add trucks with '07 engines to your fleet would be the way to go. After all, CJ-4 oils are compatible with earlier engines, and there's little doubt they provide better wear protection. But that decision comes at a cost: CJ-4 oils cost more.
So you're faced with a dilemma: Do you have to stock different engine oils for pre- and post-'07 engines? That's not really an option in most fleet shops. The potential for confusion is just too real.
Do you switch to CJ-4 and take the cost hit? That may not be an option either.
Or, do you carry on with the previous CI-4 Plus oils and deal with the accelerated plugging of the DPF?
In some cases, there might not even be a choice, according to comments made at the spring meeting of the ATA's Technology and Maintenance Council. It may depend on what your lube supplier is going to provide. One fleet maintenance manager complained that his local supplier was making CI-4 oil available only in gallon jugs and CJ-4 oil in drums, forcing him to switch. Another said his supplier was doing just the opposite, thus preventing a switch.
And how many '07 engines do you have, anyway?
Confusing the issue even more, the engine OEMs seem ambivalent on the subject. Where, initially, they were saying you'd be ridiculed before your peers, tarred and feathered and run out of town on a rail if you didn't use CJ-4 with '07 engines, now they are backpedaling, saying nothing hugely disastrous will happen if you use the old category lubricant, just shorter DPF maintenance intervals.
I think the wild card is the wear factor. As part of the roll-out for the new category oil, we've seen some good evidence that formulating to meet the standard has resulted in significantly improved wear protection. To borrow a hackneyed phrase, it's a new paradigm.
But if you trade at 450,000 miles, is it a paradigm you want to shift to?
I guess it will play out as the '07s get into the fleets. The CJ-4 oil will likely get less expensive, the supplies will smooth out, the fleet experience will show returns on the investment. Maybe even retained values will be impacted by lifetime use of the low-wear lube.
The only way is to put it on a spreadsheet and keep track. The numbers, that is. CJ-4 oil makes just as much mess on a spreadsheet as a CI-4, and it gets really hard to read the numbers.
