Shell Lubricants predicts that most fleets will switch over to motor oils meeting the new API CJ-4 service category in spite of the fact that CJ-4 was engineered for use in 2007 engine models. Shell said this is because carriers are unwilling to risk using the wrong oil in the wrong engine.
“The fleets we are talking to are really worried about co-mingling CI-4 Plus—the oil currently used for their existing engines—with CJ-4. And if they don’t use CJ-4 in their new engines, they may invalidate their warranties and that’s an expensive mistake to make,” said Dan Arcy, Shell’s technical expert.
Arcy added that the drawbacks to using CJ-4 fleet-wide from both a cost and maintenance perspective are very low, given that Shell has accumulated several hundred thousand CJ-4 test miles across a variety of engine models.
Though CJ-4 will cost 10% to 15% more than CI-4 Plus, its new chemical formulation will boost wear protection for both ’07 and pre-’07 engines alike, and without affecting current drain intervals for most fleets, according to Shell.
“Our CJ-4 blend has a total base number (TBN) of 10.5 compared to CI-4’s TBN of 11.5,” Arcy explained. “For on-highway fleets, then, their drain interval won’t need to be changed. Only off-highway fleets still using regular diesel fuel [with a sulfur content of 500 parts per million] may need to change drain intervals with CJ-4.”
He added that Shell’s CJ-4 field testing with pre-’07 engines with 200,000 miles showed metal wear reduction rates 29% lower than with CI-4 Plus. Though he stressed that those CJ-4-filled engines need to reach 500,000 miles and go through a tear-down study for a final wear analysis, these initial results show the oil provides substantially better protection in older model engines than “cheaper” CI-4 Plus blends.
“Less wear translates to better engine cleanliness and that’s very important, especially for ’07 engines as they run hotter and create higher levels of piston deposits,” Arcy said.
“You see, what’s going to drive diesel particulate filter (DPF) maintenance cycles is how much ash they accumulate, and ash formation in the filter is a direct result of how much engine oil gets burned up in the combustion chamber,” he said. “So the cleaner the engine, especially the piston rings, the less ash gets trapped by the filter, resulting in a longer DPF maintenance interval.”
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