"Synthetic oils, such as the popular Mobil 1, are stretching oil change intervals, leaving the 3,000-mile mark in the dust. "The great majority of new vehicles today have a recommended oil change interval greater than 3,000 miles," said Mobil spokeswoman Kristen A. Hellmer. The company's most advanced synthetic product (Mobil 1 Extended Performance) is guaranteed for 15,000 miles.
Today's longer oil change intervals are due to:
Improved "robustness" of today's oils, with their ability to protect engines from wear and heat and still deliver good fuel economy with low emissions
More automakers using synthetic oil
Tighter tolerances (the gap between metal moving parts) of modern engines
The introduction of oil life monitoring systems, which notify the driver when an oil change is required and are based on the way the car is driven and the conditions it encounters. Sixteen of 34 carmakers now use oil life monitoring systems in their 2013 model-year vehicles, including all three domestic automakers. That represents a majority of the vehicles sold in the U.S.
One GM car Edmunds drove went 13,000 miles before the monitoring system indicated the need for an oil change. We sent a sample of that oil to a lab for analysis. The results showed that the oil could have safely delivered at least another 2,000 miles of service."
""Regular oils" are mineral-based products refined from crude oil taken from the ground. Over the past 20 years these lubricants have been refined even further, particularly in the area of viscosity enhancers. This means modern oils flow better over a range of temperatures. This, in combination with engines that sport tighter clearances and better machining, allow for the use of thin oils that both reduce friction and improve fuel efficiency. For instance, in the world of racing, very few teams are going to be using motor oil with single rated viscosity. Racers not only want efficient operation and greater power, they want the best lubrication of engine parts as quickly as possible. (Start-ups deliver high engine wear, so you want an oil that gets to work quickly.)
"Synthetic oils", which have been around since the 1970s, have the same natural ingredients as "regular oils" but they are distilled in a chemical plant where the concept of refining goes techno-geek. Try wrapping your head around the concept of “synthesized-hydrocarbon molecular chains” and base fluids including “polyalphaolefin, synthetic esters, and alkylated aromatics.” What the heck do all these terms mean? In plain english, they are the engineered basis for the synthetic oil qualities listed below.
are all season and have multi-viscosity properties, some flowing as much as seven times faster than regular oil.
can stand extremes of engine temperature (some above 400°F) more efficiently.
can boost horsepower more effectively than thinner regular oils.
can be used for intervals as long as 25,000 miles before requiring an oil change.
contain fewer contaminants like sulfur, wax, and other elements that contribute to sludge build-up.
Of course, synthetic oils are more expensive and there are some things they don’t do, including:
eliminate the need for oil changes.
or eliminate engine wear.
The major advantage of synthetic oils is superior lubrication that significantly reduces engine wear over the long term."