Debating The Use Of Synthetic Oil

Recently I’ve been getting a lot of questions about the use of synthetic motor oil in vehicles, such as: Should I use synthetic oil? Does it work better in some cars than others? Does it cost more? Do I have to change the oil more frequently? Less frequently? Does it make my engine last longer?

First of all, let’s take a brief look at the history of synthetic motor oil and its introduction to the marketplace.

AMSOIL Inc. developed the first synthetic motor oil to meet API service requirements for use in passenger vehicles. Lt. Col. Albert J. Amatuzio, founder, president and CEO of AMSOIL Inc. witnessed synthetic lubricants in action as a jet fighter squadron commander. Synthetic oils were developed for (and still are used exclusively in) aircraft jet engines because of their extraordinary ability to reduce friction and wear on engine parts. Good synthetic oil has an incredible ability to function dependably at severe hot and cold temperatures as well as to withstand rigorous and lengthy engine operation without chemical breakdown resulting in “Viscosity Breakdown” or the inability of a fluid to flow.

This is critical in aircraft engine operation because, if oil breaks down at 30,000 feet, aircraft engines can fail and – well, you get the picture. Amatuzio decided that he would develop synthetic motor oil to be used in automobiles in hopes of realizing the same benefits in passenger cars as in aircraft engines. In 1972 AMSOIL rolled out the first synthetic motor oil for automotive applications. In the early seventies, another company was also working on synthetic oil development for the automobile – Mobil Oil Company. They came to market with synthetic motor oil in 1975; you might know it as “Mobil One.” By the 1990s the other major oil companies added their synthetic oils to the marketplace, in addition to their petroleum-based products.

To understand synthetic motor oil, let’s first look first at the origins of all motor oil. Conventional oils come from crude oil that is pumped from the ground. In an oil refinery, crude oil is separated into various fractions. These fractions become the bases for lubricating oils and fuels. The part of crude oil that forms thick tangled masses of carbon chains is used in roofing tar and roadwork. Very short chains and ring compounds of carbon are volatile and can be refined to produce gasoline and other products. All motor oils are made up of base oils and additives. In general, fully synthetic motor oils contain non-conventional, high-performance fluids, which make good quality synthetic motor oil tougher than non-synthetic. Synthetic blends usually use some non-conventional, high-performance fluids in combination with conventional oil. It is the unique chemical formulation of synthetic oil that causes it to be highly resistant to viscosity breakdown from high temperature, friction, and chemical contaminants. Now that we have the elementary out of the way (I feel like I should say “Watson” at this juncture!) Let’s move on to the most popular Q&A surrounding synthetic motor oil.


That depends on the vehicle’s age, mileage, and the carmaker’s recommendations for engine lubricants. Older vehicles with high mileage tend to have excessive mechanical wear in the engine, allowing for internal oil leakage. On vehicles with high mileage, it is not recommended to use full synthetic oil because it is thin and very free flowing, and use of it does (more often than not) result in internal oil combustion (or burning). I used full synthetic oil in a Plymouth Neon I owned years ago. After logging 120,000 miles the car started to consume oil at an alarming rate. Concerned, I switched to semi-synthetic oil that was more full-bodied and the consumption stopped. I logged another 30,000 miles and sold it. Carmakers use full synthetics and semi synthetics in some of their engines today. In most cases, you will find that a synthetic lubricant is used when there’s a high performance engine with tight engine tolerances, high compression, and high operating temperatures. Follow your owner’s manual for motor oil recommendations. If you want to use synthetic oil and your car is still under warranty, check with your local dealer before switching to synthetic oil (just to make sure you’re covered with the switch).


As I stated earlier, some carmakers recommend only using synthetic oil in their engines. For instance, Chevy recommends the use of Mobil One full synthetic oil in its Chevy Corvette engine. I have used synthetic oil in all of my vehicles for the last twenty years with great results, with one exception. I didn’t use a full synthetic in my Ford Taurus 3.0 DOHC V-6. Ford specifies using a 5W20 semi-synthetic due to engine design, so I followed the manufacturer’s specification. Remember, before changing to synthetic oil, check with your dealer and/or owner’s manual on carmaker’s recommendations/caveats. As stated earlier, you could void the warranty if the use of synthetic is strongly prohibited. Also, if your car is equipped with an oil life monitor calibrated for use with conventional oil, forget following the dictates of this system, as good synthetic oil will outlast oil change intervals laid down by the oil life monitor. Just change it every 5,000 to 7,000 miles; that should cover just about all applications.



It flows easier in cold weather, therefore no loss of prime when the oil is cold. Also, it is highly resistant to viscosity breakdown (the ability of the oil to flow easily in all temps) from heat, friction, and chemical contaminants.

Longer change intervals: 5,000 to 7,000 miles between oil changes (compared to 3,000 for regular oil). Some folks have documented up to 25,000 miles between changes. However, I would not advise going that long. It just makes me nervous based on my experience as an automotive machinist.


Cost is twice as much as conventional oil per quart. However it lasts longer, so the actual cost increase is closer to 50 to 60 percent.

Flows easily, therefore not recommend for use on high mileage engines; nor do I recommend using it in new engines during the break-in period because it is so slippery and dramatically limits the wearing of new mating parts within the engine. This initial wearing of parts is what makes for proper engine break-in, sealing of piston rings, mating of camshafts and lifters, etc.


Yes, because it is so slippery, synthetic makes for less engine wear and cooler operating temps; thus resulting greater engine longevity. In addition, because of its chemical makeup, it better withstands the rigors of the internal combustion engine (hot, toxic, under extreme friction; sometimes very cold – and thus dry – during winter startup). Good synthetic oil flows better than conventional oil in cold climates because it maintains its viscosity in a wide range of operating temps.

‘Til next time … Keep Rollin’

Tom Torbjornsen is an automotive expert of 38 years. An automotive journalist in good standing with the International Motor Press Association and Motor Press Guild, Torbjornsen has been the Repair and Maintenance editor for AOL Autos, At Home Portals, and many other websites. Hear his radio show AMERICA’S CAR SHOW, locally on AM1340 WKSN via the SSI Radio Network Saturday mornings at 8. See Tom’s television show, “America’s Car Show” on Buffalo’s all new WBBZ TV, Channel 5 on Dish, channel 67 over-the-air and on Direct TV. The show airs weekly Wednesday nights 6:30-7 p.m.. It is re-aired on Thursday mornings at 9 a.m. and Saturday mornings at 11 a.m.. For more info on Tom Torbjornsen, visit AMERICA’S CAR SHOW website at You can send Tom your car questions and TV show topic suggestions at: Find Tom’s book, “How To Make Your Car Last Forever” in local Barnes & Noble booksellers and