Is Synthetic Oil a Better Purchase

Does your vehicle run off synthetic oil? Whats better? The regular petroleum based oil or the synthetic oil that supposedly lets your car run twice the amount miles. Synthetic oil has been on the market as early as 1970. Is it worth the purchase, and is it better for your vehicle? Here are some of the advantages and disadvantages of replacing your oil with synthetic:

Advantages

The technical advantages of synthetic motor oils include:

• Measurably better low and high temperature viscosity performance



• Bette chemical & shear stability



• Decreased evaporative loss



• Resistance to oxidation, thermal breakdown and oil sludge problems



• Extended drain intervals with the environmental benefit of less oil waste.



• Improved fuel economy in certain engine configurations.



• Better lubrication on cold starts

Disadvantages

The disadvantages of synthetic motor oils include:

• Initial costs are usually four times greater than petroleum-based oils, though at one time, man-made oils cost ten times more than petroleum. Initial costs are often mitigated by extended change intervals, which individuals may confirm through used oil analysis (UOA).



• The lower friction may make them unsuitable for break-in (i.e. the initial run-in period of the vehicle) where friction is desirable to cause wear.



• Improved engine part machining has made break-in less critical than it once was though. Many modern cars now come with synthetic oil as a factory fill.



• Potential decomposition problems in certain chemical environments (industrial use dominantly)



• Potential stress cracking of plastic components like POM (polyoxymethylene) in the presence of PAOs (polyalphaolefins).



• Potential on some older pushrod race engines with roller lifters for the roller itself not to spin with camshaft movement, but rather slide while the roller itself remains either stationary or at a lower circumferential speed than that of the camshaft lobe.

In July 1996, Consumer Reports published the results of a two year motor oil test involving a fleet of 75 New York taxi cabs and found no noticeable advantage of synthetic oil over regular oil. In their article, they noted that "Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service - stop-and-go city driving." According to their study, synthetic oil is "worth considering for extreme driving conditions: high ambient temperatures and high engine load, or very cold temperatures." This research was criticized by some because most engine damage appears to be caused by cold starts, and their research method may not have included enough cold starts to be representative of personal vehicle use.