PC-11 oils and maintenance intervals: What fleets should expect

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Fleet Owner / August 13, 2015

New Proposed Category 11 heavy duty specification oils are on their way and before long will be in use at a fleet shop near you. Should fleets expect anything different in terms of oil and oil filter maintenance when they make the switch?

Yes, says Edward Covington, vice president of global quality for WIX Filters, at least theoretically, “but you’ll have to watch it.” He shares some considerations for fleets as the new-spec oils approach their market debut, which is now anticipated as early as December 2016.

As a starting point, PC-11 oils are being designed to tougher standards, like higher shear and oxidation stability and better resistance to aeration, adhesion wear and thermal breakdown, Covington points out. The main drive to develop oils with upgraded performance is so they can maintain effective protection at lower viscosities in hotter-burning, more fuel-efficient, lower-emissions diesel engines on the way. Thinner viscosity oil means less resistance on the engines' moving parts, and thus less fuel that'll need to be burned to move them.

"What we've seen over time is that oils and filtration have improved along with engines as new specifications, technologies and additives have come out," Covington says. Oil filtering media also have evolved considerably over time to better protect against wear, he adds. "So generally, we expect that the new PC-11 oils are going to be more robust and resistant to breakdown," so the question is whether the oils, with proper filtration, will mean longer usable maintenance intervals. Covington notes that the oils' formulations are proprietary and still under development by a number of oil companies.

One of those is Chevron, whose Shawn Whitacre, senior engineer for engine oil technology, also recently became chairman of ASTM International's Heavy Duty Engine Oil Classification Panel. There, according to Whitacre, "We're responsible for establishing the spec itself — particularly the new tests and limits that will be associated with those tests, and incorporating that into the official ASTM spec that defines oil quality.

"The thinking of the industry is that these are going to be higher quality products than those they replace," he continues, agreeing that compared with the current CJ-4 heavy duty oils, "I think there's a lot of merit to the thought that these new oils will have the capability to go longer."

Ultimately, however, engine makers will have to make their own recommendations about oil and filter maintenance intervals with the new oils, Whitacre notes. "It's the OEMs' decision how they intend to leverage this expected performance improvement in terms of the recommendations they make for their new products," he says, "as well as for their existing and older products."

In addition to following OEM engine service recommendations, Covington suggests that fleets monitor and test their oil to determine what the optimal maintenance intervals should be for their specific engines, oil, fuel type and operating conditions. "If you look at it, some fleets are probably changing [trucks' oil and oil filters] too soon now and they could be going longer, and others are probably going too long now and they should be changing oil and filters more frequently," he contends.

Regardless of PC-11 oils' potential performance, Covington notes that environmental and operating conditions play a big role in (e.g., can shorten) usable oil life — things like lots of dust or moisture in the air or frequent stop-and-go traffic backups. "How and where a vehicle is being run is a significant part of it," he says.

Proliferation effect

The WIX exec has a few recommendations particularly for when a fleet makes the switch to a PC-11 oil, noting that two subcategories of PC-11 oils are expected. "PC-11A" oils will be available in the same types and viscosities as current-spec oils, just with upgraded protection against wear and breakdown, and will be compatible with older vehicles. It's not known yet how compatible the "PC-11B" special lower viscosity oils will be with older engines — those are being designed to work in 2017 diesel engines and help deliver better fuel economy and lower greenhouse gas emissions.

That leads to what Covington calls "a proliferation effect" when the variety of PC-11 products arrive. There will be more oils available — those that meet or don't meet the PC-11 standards, different viscosities of both those, two separate categories of PC-11, etc. — making it easier to fill a truck with the wrong one.

If that happens, "the filter itself can handle the wrong oil, but higher wear on the mechanical parts of the engine, higher oil consumption or 'wash down' [of fuel into oil] may result in premature filter plugging due to oil breakdown or related concerns," Covington says, noting that PC-11 oils also are being designed to accommodate biodiesel.

"The harsher the duty cycle, the more likely wash down may occur when switching oil types — brands, base stocks, chemistry," he explains. "Oil analysis will aid in determining if the viscosity, wear metals or soot levels change to an unacceptable point."

Covington recommends that fleets run oil analyses prior to using a PC-11 oil and right after the switch on the same vehicle to establish their effective oil and filter drain interval.

"Then monitor oil usage (top off), make sure the correct viscosity is used for the specific engine and use a backward-compatible version of PC-11 as needed for older engines," he adds.

Whitacre agrees oil analysis can help. "That would be a good approach to really be methodical about understanding how the oil performs and if they might be able to take advantage of these new [performance] properties," he says. "That's one approach that fleets take — especially those that are trying to utilize oil analysis to optimize their drain intervals."

The bigger performance leap: PC-11B

For vehicles currently on the road, Whitacre notes that the PC-11A category oils will offer the simplest transition. "Those products will be able to be used quite transparently with products that are made and sold today, and they'll likely have the broadest applicability across fleet owners, off-highway equipment and so on," he says.

While the PC-11A products are targeting better performance and perhaps could offer longer maintenance intervals, Whitacre points out that fleets will likely wish to consider the PC-11B products that promise higher fuel economy as well. "It certainly isn't too early to begin discussions with their suppliers — whether that's their oil supplier or engine maker — about what options are going to be available to them, particularly in getting the OEM position on [using] the new viscosity grades," he says.

Again, the PC-11B oils may not be backwards-compatible with older engines, but assuming a fleet could use them, what about oil and filter maintenance intervals then?

"We expect they'll also be very robust products, but it's a little hard to tell at this point whether they'll offer opportunity for drain interval improvements," Whitacre says.

Roma Fatima, lube filtration product manager at Cummins Filtration, offers some additional thoughts on the matter. The company announced its new filtration product aimed specifically at PC-11B oils earlier this year, as other filter companies no doubt will in the months to come.

"Advanced filtration technology is certainly an essential part of a successful relationship between these improved engines and lubricants," she tells Fleet Owner. "The goal of the lube filter is still to protect internal engine components based on the engine's filtration requirements . . . however, the nature of the lower-viscosity oils can change some aspects of how the filter is able to do its job." Fatima also emphasizes that regardless of any performance claims of oil filter products designed for PC-11B oils, the oil filter doesn't determine maintenance intervals — OEMs will have to make their recommendations for specific engines.

Still, if PC-11B oils should offer longer usable life, from her company's perspective at least, she contends that Cummins Filtrations' new filter could support it. "If the condition of the oil warrants a longer service interval, then Fleetguard lube filters featuring NanoNet media are suitable for those extended service intervals and will provide improved performance," she says.

Related reading:

http://www.bigmacktrucks.com/index.php?/topic/35713-test-development-proving-tricky-for-new-pc-11-engine-oil/?hl=pc-11

http://www.bigmacktrucks.com/index.php?/topic/32540-lower-viscosity-pc-11-and-oils-role-in-fuel-economy/?hl=pc-11

http://www.bigmacktrucks.com/index.php?/topic/40417-shell-says-backwards-compatibility-for-pc-11b-fuel-economy-oils-not-ruled-out/?hl=pc-11

http://www.bigmacktrucks.com/index.php?/topic/39540-separate-oils-for-newer-and-older-engines-being-developed-for-heavy-duty-trucks/?hl=pc-11

http://www.bigmacktrucks.com/index.php?/topic/33481-new-oil-choices-thick-or-thin/?hl=pc-11

http://www.bigmacktrucks.com/index.php?/topic/35731-shell-engine-teardown-compares-protection-of-experimental-oil/?hl=pc-11