How to Measure Motor Oil Quality

Published: 05th March 2010
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Cutting expenses on your choice of motor oil could end up costing you more in the long run. You don't need to be a mechanic to determine some of the best oils on the market, just simple research and few simple test will point you in the right direction.

Do you agree with this statement; "oil is cheap insurance so change it often.Oil isn't cheap when you discover that you just blew up your engine, don't believe the old adage that "oil is cheap". Since oil is the lifeblood of your vehicle it only makes sense to look at higher quality full synthetic oils on the market?

Why do people not bat an eyelash when they spend $25,000, $30,000 or as much $35,000+ for a new vehicle then head to a discount retailer to buy the cheapest oil they can find on sale. Don't fall for these old wives tales, technology has changed over the last 30 years and there are some excellent synthetic oils out there.

It's easy to determine what the best oils are once you understand the different classifications of oils. For the sake of this article we are only going to talk about synthetic oils. The time is nearly here that even some of the better petroleum oils on the market will eventually be obsolete soon because their limits have been reached.

If you want to separate the different synthetics on the market there are really 3 classes. Semi--synthetics, Group III synthetics and Group IV synthetics. Without getting into the chemical makeup of these oils we will attempt to explain the difference.

Semi--Synthetics are simply that, part petroleum part synthetic. The problem with these oils is there are no guidelines in place that says how much synthetic oil has to be in the formula. Some reports state that as little as 5% of the product can contain synthetic oil and be labeled a semi--synthetic oil. When we think of semi--synthetic we naturally think it will be a 50/50 mix, nothing could be further from the truth.

Group III synthetics are actually petroleum based products, but because of a ruling in the late '90's manufacturer's are permitted to label them as synthetic oils. The bottom line is Group III synthetics are actually petroleum oil that have gone through an extra refining process known as hydrocracking. This is a process where petroleum oil has undergone an extra process to eliminate more of the impurities in crude oil. Group III synthetics are the most popular on the market today, but do not offer the best protection.

Group IV synthetics are clearly true synthetics. If you find an oil that recommends a drain interval such as 25,000 miles then you can be fairly certain that this oil is made from a Group IV basestock. As of this writing there are 3 synthetic oils on the market that are independently recommending specific drain intervals outside the traditional recommendations made by car manufacturer's and the national quick lubes.

Two of these manufacturer's recommend 15,000 mile oil change intervals and one manufacturer recommends 25,000 mile change intervals. These oil change intervals do not void any car manufacturer's warranty and at least for one of these companies they have been practicing 25,000 miles intervals since 1972 without any interference from auto manufacturer's.

The price of a high quality synthetic oil should be the last thing you consider. A good synthetic oil will give you longer drain intervals and better fuel mileage. Additional facts can be found on the internet about these oils and we highly encourage you to investigate this further. Extending your drain intervals is not only safe, but permitted in every vehicle on the road.


Author-Steve Tarini is a veteran tester of motor oils and lubricants. After 14 years of testing motor oils determining the Best Synthetic Oil hasn't been easy. When you Compare Synthetics it is important to use independent test methods

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