Extending oil drain intervals has been a hot topic for a number of years as fleets look to stretch more bang from their advanced engine fluid buck, but extending intervals doesn’t necessarily mean exceeding OEM recommendations.
When the current generation CK-4 and FA-4 oils were released in late 2016, many engine OEMs boosted oil drain intervals for model year 2017 and newer engines by as much as 15,000 miles under certain conditions and duty cycles.
For large carriers – often emboldened by a more direct relationship with their OEM, which can give them certain advantages in maintenance practices – BP/Castrol Field Engineering/Heavy-Duty Technical Services Manager Jami Melani said the longer OEM intervals probably added an extra margin of security as many fleets were already extending oil drains well beyond OEM recommendations.
“At the other end of the spectrum, although it is hard to believe, there are still people changing oil at extremely short intervals,” Melani said, “as low as 15,000 miles.”
Several factors have led engine OEMs to sign off on extended drain intervals. Modern engines generate less soot and ultra low sulfur diesel fuel has lowered acid levels in oil, helping improve the oil’s ability to protect metal parts. “It’s a little milder environment in the crank case these days,” said Stede Granger, technical services manager for Shell Lubricants. “Changing your oil doesn’t hurt the truck a bit, but draining at 20,000 miles these days is really probably overkill.”
Exxon Mobil Commercial Vehicle Lubricants Applications Engineer Paul Cigala said smaller carriers tend to be more conservative and hesitant to change cyclical maintenance intervals, even when the OEM says it acceptable to do so.
“To them, oil is a cheap option and they’re willing to change it out early,” he said. “[An oil change interval] either fits into their service intervals, their inspections … it fits into something. Hard to teach an old dog new tricks.”
