API CK-4 and FA-4 heavy duty engine oils have the distinction of being the most expensive ever developed. With a price tag estimated at nearly half a billion dollars to develop and deploy, the cost of getting these oils to the starting line has been more than double that of CJ-4 oils. But now that the products are off to the races, there seems to be a good deal of confusion about them in the marketplace.
Unfortunately, when there is confusion, there is also an increased likelihood that things will go wrong. Understanding how starts with a look at some of the fundamentals of CK-4.
The American Petroleum Institute approved the new HDEOs for first use on Dec. 1. With enhanced oxidation stability, high-temperature high-shear stability and superior aeration resistance, CK-4 offers an opportunity to further extend drain intervals and improve engine durability. Building on these advantages, FA-4 oils offer improved fuel economy (0.5 to 0.7 percent higher for the same viscosity grade) and reduced greenhouse gas emissions. The CK-4 and FA-4 oils are clearly an upgrade from CJ-4 products.
Although there is nothing particularly confusing about the advantages the new oils offer, it gets a bit complicated when one looks at some of the subtleties of the old and new specifications.
Appreciating these details starts with understanding that the C in an API service category indicates the engine oil is designed for use in diesel engines, while S is for gasoline engines. Engine oils bearing only the CJ-4 mark, for example, are designed for use only in diesel engines. But there are also engine oils denoted CJ-4/SN, which can be used in both diesel and gasoline engines. They are often referred to as universal oils. This brings us to the first subtlety concerning CK-4 and FA-4 and the source of both confusion and concern for some.
Understanding that there is a limit of 800 parts per million phosphorus for API SN Resource Conserving/ILSAC GF-5 oils to protect catalytic converters, how can a CJ-4 oil, which is typically packed with 1,000 to 1,200 ppm phosphorus to protect heavy duty diesel engines from wear, meet the API SN specifications?The answer is what some refer to as a loophole in the specifications.
The API S service category standards for phosphorus do not apply if API CH-4, CI-4 or CJ-4 categories precede the S category, and there is no API certification mark on the product label. In addition, the phosphorus standards dont apply to API SN oils for such non-ILSAC viscosity grades as 15W-40. While this issue and the endless debate that surrounds it will fade away as CJ-4 rides off into the sunset, similar concerns are already being voiced about CK-4. This is because, although narrower than the loophole seen in CJ-4, CK-4 also allows licensing space for oils to meet both diesel and gasoline engine oil specifications.
As with CJ-4, there is an upper limit of 1,200 ppm on phosphorus for API CK-4/SN 15W-40 oils. An interesting change, however, is that although there is a 1,200 ppm phosphorus limit for all viscosity grades of CJ-4 when the designation precedes the S category without an API certification mark on the product label, there is an 800 ppm maximum on phosphorus for CK-4/SN oils in the viscosity grades of 5W-30 and 10W-30. These seemingly subtle distinctions have also become a source of concern. Specifically, some see potential compromises in performance when using engine oil made to serve two masters: diesels and gas engines. From there, the number of questions grows and the debates amp up.
Ford, for example, has concerns that the phosphorus level for the 5W-30 and 10W-30 viscosity grades is too low to protect its diesel engines from wear. Because of this, the company does not recommend using CK-4 and set a minimum of 1,000 ppm phosphorus for oils used in their diesels. The significance of this is particularly important when one considers the large number of Ford 6.7-liter diesel engines currently on the road.
Another issue that has come up is the utility of an API CK-4/SN oil when no heavy duty engine manufacturer has specified the use of SN/GF-5 10W-30 oils for gas engines since 2012, and none recommend SN-only engine oils. Further, although 5W-30 continues to enjoy significant market share with gasoline engines, what is the value of using a CK-4/SN oil that does not meet ILSAC fuel economy requirements? Most new vehicles are using XW-20 engine oils-a viscosity that cant be used in heavy duty engines. To make things even more interesting in the short term, no diesel OEM actually requires the new CK-4 or FA-4 oils in their engines-but that should change by 2018.
While the list of questions and concerns the market has about CK-4 and FA-4 is long, you can be sure these will eventually sort themselves out. In the meantime, there is another concern worthy of mention: How can we educate end-users to protect them from unscrupulous suppliers trying to exploit loopholes in HDEO specifications at the cost of the end-users equipment?
Tom Glenn is president of the consulting firm Petroleum Trends International, the Petroleum Quality Institute of America, and Jobbers World newsletter. Phone: (732) 494-0405. Email: tom_glenn@petroleumtrends.com