April 19, 2018
By Thomas F. Glenn, President
Petroleum Quality Institute of America
The Petroleum Quality Institute of America (PQIA) is pleased to announce updates to its Quick Reference Guides for passenger car engine oil (PCEO) and heavy-duty diesel engine oil (HDEO) timelines. In addition to including the new API SN Plus specification for PCEO, the timelines are expanded to include ILSAC and General Motors dexos® specifications and additional detail as to applications.
The PQIA timelines provide a quick and easy to use reference to help installers, retailers, consumers, and others understand and identify current API Service Categories, ILSAC designations and dexos® specifications. Importantly, they also help buyers to distinguish products with current specifications from those with prior and/or obsolete specifications.
Important Points to Consider When Referencing the Timelines
As shown on the timelines, it’s important to note that most engine oils are back serviceable to older API Service Categories. Engine oils meeting API SN or API CK-4, for example, will meet API SM, and CJ-4, or older categories, respectively. This does not, however, apply to API FA-4 which has no back serviceability (Detroit Diesel allows limited back serviceability outside the API system) and will not apply to future ILSAC GF-6B or current API SN/SN Plus, for SAE 0W-16 engine oils.
Rather than a hard and fast break from previous API Service Categories, passenger car engine oil In North America typically transitions to the newest specification. This transition usually takes 12 months or less to reach near completion, as most recently seen when ILSAC GF-5 (API SN/Resource Conserving) replaced ILSAC GF-4 (API SM/Resource Conserving). It is important to note; however, the transition is never fully complete since some marketers, albeit few, continue to sell older and even products meeting obsolete service categories. Importantly some of these products can cause harm to an engine and/or void a vehicle’s warranty.
For these reasons, consumers are advised to read the labels on the bottle of oil prior to purchase, and look for the API Service Category, viscosity grade, and other pertinent specifications when you have your oil changed. These specifications and others (i.e. dexos®) should be consistent with those recommended by the vehicle manufacturer for the make and model year. In addition, whereas API SN Plus becomes the most current API Service Category on May 1, 2018, it will take time for these products to migrate into the market. Understanding, however, that many lubricant marketers have already announced their products are now formulated to meet API SN Plus, such products are expected to be readily available in the market shortly after they can be officially licensed on May 1st. Unlike previous API “S” category updates, API SN/GF-5 or API SN Plus/GF-5 can both show the ILSAC starburst, so consumers with newer vehicles with gasoline direct injection (GDI) engines will need to check the API donut for API SN Plus and not just the ILSAC starburst. it is expected most marketers will convert all their PCEO to API SN Plus and transition will take place quickly.
Specific to HDEO, the transition to the latest service category typically takes 6 to 12 months. It can, however, take longer as seen when the market moved from API CI-4 to CI-4 Plus. In this case the transition nearly spanned two API Service Categories (CI-4 Plus and CJ-4) before CI-4 moved to near extinction in North America.
Similar co-existence between Service Categories was also seen when CJ-4 replaced CI-4 Plus. CI-4 plus existed for several years before most marketers went to all or mostly API CJ-4. According to many marketers, the higher cost of CJ-4 and different needs between on and off-road vehicles impacted the CI-4 Plus and CJ-4 transitions.
In addition, the transition was also said to be slowed by end user concerns about CJ-4 constraints on Sulfated Ash, Phosphorus, Sulfur (SAPS). Although ultimately accepted as a nonissue, a significant number of end users initially believed the limits on SAPS, which resulted in a lower total base number (TBN), compromised the product’s ability to provide an adequate level of detergency and wear protection.
In conclusion, the PQIA Quick Reference Guides provide an excellent resource for consumers, end users, retailers and others to help understand the many “codes” on engine oil labels that identify the performance level/specifications of the products in the market, and ultimately the products used in their vehicles. Although there are exceptions, the most current API Service Category is backward compatible. This means, in most cases, products labeled as meeting the most current specification can be used in older vehicles. Consumers should also be aware that although it can take a year or so for products with the most recent specification to transition into the market, products meeting only obsolete specifications remain in the market; these engine oils can damage an engine and/or void warranties. Always consult your owner’s manual for the correct viscosity grade and performance specification(s) required for your vehicle and ask questions about the specifications when getting your oil changed.
Please contact PQIA if you have any questions concerning these and other PQIA Quick Reference Guides.