Synthetic vs Conventional Motor Oil and Change Interval
Perhaps it's time to re-evaluate both the motor oil used in your vehicle and how often you replace it. The old rule of thumb was that motor oil should be changed out roughly every 3000 miles or every three months, depending on whichever came first. Additionally, it was generally advised to purchase conventional motor oil for standard, daily driving use and only pay the premium for synthetic oils if driving under harsh conditions. While the argument between synthetic and conventional oils has raged for decades, the change interval has happily gone about uncontested.
Lately, even generally conservative mechanics are starting to recommend increasing those intervals upwards of 5000 miles even on conventional oils. Various manufacturers such as Ford, GM, Volkswagen and BMW have published motor oil change intervals from 7500 miles through 15,000 miles when using synthetics. So what's changed? Aside from the engineering improvements and high tolerance manufacturing within the engines themselves, the technologies behind fuel reformulation (for lubricants and cleaning agents) along with motor oil technology have continued to improve as well. While conventional oils are better than they were when the guidelines were developed, synthetics beat conventional oil in virtually every category of performance. With the general dangers of engine sludge largely in the past, perhaps its time to re-evaluate both oil change intervals and adaptation of synthetic motor oil in your own vehicle.