Commercials from the makers of motor oil that boast that their product does the best job of protecting your car’s engine are standard fare. So are ads that fling charges against rival oils, such as the Castrol Edge spots that claim that the motor oil provides eight times better wear protection than Mobil’s does. Common to all of the ads, it seems, are warnings that your vehicle’s engine is at risk from friction, sludge, varnish and wear from motor oil than can be contaminated, oxidized, cooked or otherwise broken down.
The fact is that virtually every motor oil that is sold these days will deliver ample protection for the types of automobiles that most of us drive—provided, of course, that the oil is changed on schedule and that the oil meets the automaker’s engine requirements.
Unfortunately, the differences between the motor oil brands increasingly are blurred, and manufacturers are secretive about their testing. This means that you get—at best—a blend of hype and facts.
SYNTHETIC CLAIMS. Although there used to be strict government standards regarding what motor oil qualified as a synthetic oil, those definitions no longer apply. Oil-makers increased the processing of their oil, and the federal government responded by expanding its definition of what qualifies as a synthetic. The murkiness of government standards and the lack of third-party testing has resulted in a war of words among competitors. (Even though industry insiders might debate just how refined oil must be to qualify as a synthetic, you should know that synthetic oils all deliver comparable performance.)
It’s enough to make your head—if not your wheels—spin.
“I tell people that ninety-five percent of the words on a can of engine oil are marketing hype,” says James Garthe, who is an agricultural engineer at Penn State University and has conducted motor-oil research for the school. “Don’t believe all that crap that’s on there.” For instance, he says, an oil might boast of its anti-sludge properties, but “all [motor oils] have some anti-sludge additives.”
So, what you get when you buy into a major brand’s claims is a big dose of marketing. For instance, Walmart’s house brand of synthetic oil passes the stringent “Corvette” standard that General Motors has set for motor oils. (We’ll have more on that later.) It’s refined by a major oil-maker. The only thing that Walmart’s motor oil is lacking is the colorful branding and the flashy TV commercials.
After all, the raw material for synthetic motor oils and synthetic motor oil blends is still conventional mineral oil. About 5 percent of the crude oil that is pumped from the ground is suitable for making motor oil; that’s what’s called the base stock—the base oil that comprises most of each quart that you buy. Whether it’s marketed as conventional, synthetic or a blend, motor oil typically falls into four different categories—Groups 1 through 4—says Thom Smith of oil-maker Ashland Valvoline. The higher the group number is, the greater the amount of processing that’s been done to the oil (to make the oil’s molecules behave more predictably)—and the more expensive that the oil is.
“Synthetic doesn’t have a lot of meaning anymore,” concedes Matthew Snider of GM. “A variety of products can be legally marketed as synthetics.” All that the term synthetic means is that Federal Trade Commission deems that the oil has been sufficiently processed and modified to qualify as “synthetic.”
What you need to know about synthetic motor oil is that it’s widely accepted that any motor oil that is classified as a synthetic delivers better protection than conventional oil does against thermal breakdown—the tendency of the oil to deteriorate (and thus not lubricate as well) when it’s heated. It also curtails wear, increases resistance to contamination, provides better flow at cold temperatures, and reduces sludge and deposits on piston rings. In other words, even though you’ll pay more—typically $1.50 to $3 per quart—for a synthetic motor oil than you would for a conventional motor oil, you’ll get more in return.