As with many things in life, supply and demand can dictate terminology and opinions. There are many buzzwords and marketing stances regarding eco-friendly lubricants and many are misleading or can exploit two worthy efforts - (1) Protecting our environment; (2) Finding renewable sources.
In the life of an engine oil formulator, the decision of when to go synthetic is determined by the performance requirements of the lubricant balanced with the cost the market will bear. For consumers, choosing whether or not to purchase synthetic engine oil involved a similar thought process. Of course, you want to buy the best lubricant for your vehicle, but you have to find a balance between performance and cost as well.
Lubricant suppliers such as ExxonMobil do not recommend use of their lubricants beyond the stated shelf life. But for the average user, identifying an expired lubricant may not be as easy as it is with something such as food, where “best used by” dates are prominently displayed, and rotten food is pretty obvious. Knowing a little about lubricants can help users determine if lubricants are OK to use or should be recycled.
By now, you’re probably already using PC-11 or are about to. To date, ExxonMobil has accumulated more than 27-million miles of testing on its CK-4 and FA-4 PC11 diesel engine oil blends. The main thing fleet owners need to remember is there are two sub-categories, CK-4 and FA-4:
• CK-4 – replaces CJ-4 oils, is a higher-viscosity blend with the high-temp, high-shear qualities needed for older-style diesel engines and is back-serviceable.
• FA-4 – In order to meet increasing emissions and fuel efficiency standards, new diesel engine designs will benefit from using a lower viscosity engine oil. FA-4 does not have the same high-temp, high-shear qualities as CK-4 and is not back-serviceable.