Oil Chronicles: Oil Change Intervals
Do today's advanced oils extend drain-and-replace intervals?
Most of us remember when automakers recommended changing engine oil every 3000 miles or 3 months. Both the engines and the oils that lubricated and protected them were far less sophisticated. Engines had looser piston-ring clearances that permitted more oil-contaminating exhaust blow-by, and oils had much less tolerance to heat and contamination. The obvious answer was frequent oil changes as necessary engine insurance.
But today's engines and the oils that keep them spinning are far more advanced, so recommended change intervals have become much longer. But should we follow automakers' recommendations, change oil more frequently to be safe, or less often to save time and money?
Quaker State Technology Director Jeff Hsu recommends sticking with OEM [original equipment manufacturer] intervals. "We are oil guys, and engine guys are engine guys," he says. "We know how to make oil, they know what their engine's appetite is, and they've done a lot of engine durability testing. Synthetics give you more cushion, so you can do it when you have time, but we always go back to what OEMs recommend as the proper interval for your driving duty."
Don't oil companies that supply factory-fill oils to OEMs provide input on those recommendations? "We co-develop with them," Hsu responds. "We have a lot of activities with European and North American OEMs to develop oils and how they function in their engines."
Should oil-change intervals vary with how we drive? Yes, to some degree. "An 8-cylinder engine ages oil more slowly than a 4-cylinder because it usually isn't working as hard," Hsu explains. "But people driving just three miles a day will age their oil more quickly than those driving 10 miles a day. A lot of variables are involved -- duty cycle, how far you drive, operating in extreme cold or heat -- the best way to recommend an interval is to let the OEMs determine it."
Hsu adds that he changes his own oil much sooner than recommended. "Oil is the cheapest maintenance I can do to prolong the life of my investment," he says. "I'm a do-it-myself guy, I enjoy it, and I'm not going to argue about $20 or $30. As a consumer, the best choice you have to prolong the life of your engine is your oil, the lifeblood of the engine."
On the other hand, some believe that OEMs recommend shorter oil-change intervals than necessary to help their dealers sell more oil and oil changes. "Manufacturers are looking to optimize their engines' durability, because they don't want a bad name," Hsu responds. "They don't want their engines having problems. They want to make sure their owners' enjoy their vehicles and get longevity out of them, and eventually come back to buy another one."
And if you are among the fortunate whose vehicles are equipped with oil life monitors (which Hsu says GM pioneered in North America but have been in European cars for some time), they will answer the question for you. There are different types -- some that directly contact and analyze the oil, others that monitor temperatures, engine revolutions and miles driven over time and calculate what percent of oil life is left -- but all provide the best possible recommendation based on how, where and how hard you drive, for when that time has come.
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