There is no need to flush an older engine when switching from CI-4 or CI-4 Plus to CJ-4. In fact, it is perfectly acceptable to top off an engine filled with CI-4 or CI-4 Plus oil with CJ-4 product.
"The CJ-4 lubricant will meet the requirements of the CI-4," says Dias. "If someone uses CJ-4 oil on top of CI-4 Plus, technically there is no problem with that because CJ-4 oil is a better performing lubricant."
If you’re not sure what product was used to fill the engine, err toward CJ-4. "If you are uncertain, put CJ-4 in because CJ-4 can go on top of CI-4 Plus without any issues whatsoever," says Arcy.
However, care must be taken not to use CI-4 or CI-4 Plus products in ’07 on-road engines. "Failure to use CJ-4 engine oils can result in damage to exhaust after-treatment systems and warranty might be denied on that basis," cautions Betner.
Arcy adds, "You are going to plug up the diesel particulate filter. You are not going to have as good of wear protection or oxidation control as you would be getting with CJ-4."
Existing engines do not pose any problems. "Your warranty for pre-’07 engines should not be affected if CJ-4 oils are used in older engines," he adds. "However, keep in mind that many engine manufacturers have additional specifications and approvals that might be included with API CJ-4 recommendations, and these requirements need to be recognized in selecting an engine oil."
The choice for off-road
For applications that do not require API CJ-4, you have a choice. This oil is a higher performance product with many benefits, but it does come at a higher price. Shell estimates the price premium could be 10% to 15%.
Fujishige adds, "The specific price increase for Chevron’s CJ-4 product has not yet been determined, but it is expected to be in the 10% to 15% range."
Since only ’07 engines require the CJ-4 oils and there is a price differential, most oil companies will offer a choice of CI-4 Plus or CJ-4 products. "In this situation, there is clearly a need to retain the CI-4 Plus oil while introducing the CJ-4 product," says Fujishige. "Although backwards compatible, CJ-4 will likely be more expensive than CI-4 Plus and is not required for the off-road market or pre-2007 engines."
Yet, stocking one product can reduce the chance of misapplication. "It gives the contractor the ability to have one product for new and old equipment," says Arcy.
CJ-4 oil may also prove beneficial if you have retrofitted diesel particulate filters to your construction equipment fleet in order to take advantage of government incentive programs. "We have heard some issues with diesel particulate filters plugging up in these retrofits a little sooner than were anticipated," says Arcy. The CJ-4 product, with its lower ash content, will allow the equipment to run a third longer before the filter needs to be serviced.
If you do choose to use CJ-4 oils across the board, you must know the sulfur content of the fuel you are currently using in your off-highway fleet. "The use of API CJ-4 oils with higher sulfur fuels, such as those currently allowed for off-highway use that may contain up to 5,000-ppm sulfur fuel, may result in modified oil drain intervals and other maintenance recommendations," says Betner. This is the result of the lowered TBN levels with CJ-4 oils.
However, the on-road fuel supply will make ULSD widely available, even to the off-road market. "In the industry, there is going to be a transition," says Dias. "Because of logistics and the fuel transportation pipelines, a lot of the off-highway market will be using ultra-low-sulfur diesel fuel. But there could be pockets in the off-highway industry where they have no access to the ultra-low-sulfur diesel fuel."
As the fuel sources switch to ULSD, and CJ-4 oils become widely accepted, CI-4 oils will eventually be phased out.
The change in the chemistry of the CJ-4 oils makes oil analysis an even more important tool. "With the CJ-4 oils, because they are significantly different, we advise our customers to start with a fresh baseline because the oils have a totally different fingerprint compared to CI-4 oils," says Dias.