So, as everyone should know by now, new truck engine oil is due to hit the market on Dec. 1 this year: PC-11, with the “PC” standing for “proposed category” though this engine oil is now far from a “proposal” since it’s pretty much a reality at this point.
I recently talked with Shawn Whitacre, senior staff engineer of engine oil technology at Chevron Lubricants, about the latest updates where PC-11 is concerned as he’s also the chairman of the American Society for Testing and Materials (ASTM) heavy-duty engine oil classification panel tasked with the final development of PC-11 oil requirements.
Most PC-11 formulations are now “locked in” and only awaiting the last sets of results from various OEM-specific bench tests. “To have products ready for the Dec. 1 licensing, testing needs to be wrapped up by April or May,” Whitacre stressed.
A final avenue now being pursued by several lubricant makers is crafting PC-11 oils that can be used in both diesel and gasoline truck engines.
“That’s more challenging because of the phosphorus limits, due to the three-way catalysts used in gasoline engines” which are 33% lower compared to diesel engines, Whitacre pointed out. “The flexibility regarding phosphorous limits goes away” when lubricant makers seek to craft such dual-performance oils. “That also forces you to use more additive chemistry,” he said.
Of the two PC-11 blends being developed, only CK-4, a 10W-30 blend, will be considered “backwards” compatible. “CK-4 will be able to claim compatibility with older 15W-40 specifications in terms of viscosity,” Whitacre noted, with CK-4 oils expected to be approved for use in many of the same engines and applications that currently recommend CJ-4.
The second PC-11 oil blend, however – FA-4 – is of a thinner viscosity than CK-4 and won’t be as backwards compatible. “FA-4 will be at a lower viscosity level than today’s oils, offering more optimized fuel economy for engines that are designed to use these thinner oils,” Whitacre noted. “Like with other low viscosity oils, we don’t expect that engine makers will allow these oils across the board.”
He said it seems that OEMs are still working on their own engine test programs at this point to determine to what extent the new FA-4 oils can be recommended – if at all.
Both PC-11 oils will be formulated to be more resistant to oxidation, meaning that they can stand up to elevated temperature for longer periods of time without breaking down. “This is something that engine makers identified as a priority because of the greater demands that new engines are placing on the oil and because engine makers continue to push for longer oil change intervals,” Whitacre said.
I also asked Brian Humphrey, OEM technical liaison-HD driveline for Petro-Canada Lubricants, for a few PC-11 insights as well.
“PC-11 is undoubtedly a step-change for the industry and reflects the needs of future engine hardware,” he emphasized. “It has been driven by many industry stakeholders and is intended to provide next generation oils expected to cope with the oxidation stability and aeration control required of modern technology.”
One of the interesting things about the thinner FA-4 “tier” of engine oil is that it should ultimately provide “lower flow resistance” with in a truck engine, meaning very simply that slightly less fuel is needed to provide the same level of power.
Yet he stressed FA-4 is also formulated to withstand a “high-shear engine environment,” meaning they could potentially be longer-lasting, thus requiring fewer oil changes.
How is that possible? Largely by the addition of specific “chemical additives” to PC-11 oils designed to protect the metallic components within engines while ensuring the oil can last a long time.
Specific additives include anti-oxidants, anti-wear, anti-foam, detergents and dispersants. Chemicals such as zinc dialkyldithiophosphates (often referred to as ZDDP so you don’t dislocate your jaw while trying to say it!) are some of the more common additives that are being used in PC-11 oils to that deliver both oxidation and wear protection.
“While both PC-11 A (CK-4) and PC-11 B (FA-4) type formulations will offer enhanced performance over current oils, the oil drain intervals are best set based on the OEM recommendations and fleet specific history based on oil drain data under actual operating conditions,” Humphrey stressed. “So the opportunity for extending drain intervals will exist, but will have to be proven viable for each fleet.”
Ultimately, in his view PC-11 should provide three main benefits for truck fleets:
- Increased durability – Downtime is the bane of any fleet operator as it reduces the capacity of their network. PC-11 products will have the potential to provide increased durability, with longer intervals between oil change periods and greater engine protection.
- Cutting emissions – Using PC-11 oils, particularly of the FA-4 tier, will improve fuel economy while also lowering carbon dioxide (CO2) emissions.
- Designed for all environments – Humphrey emphasized that Petro-Canada tests all of its engine oils in Canada’s harshest environments and most extreme temperatures, so fleet operators can be assured that its PC-11 products will provide optimum efficiency wherever and however they are being used.
Well the clock is certainly ticking on all of this. We’ll see how it all comes together when winter returns later this year.
