"For a variety of reasons," writes Bill Farlow in his regular "Under the Hood" column in Coast to Coast, "synthetic lubricants have recently attracted a lot of attention. For one thing, synthetics have proven to be, for want of a better term, more slippery. With so much emphasis on increased miles per gallon anything that can reduce friction and increase fuel mileage has come under serious consideration. Less has been said about the decreased wear from using synthetics."

Farlow notes that synthetic lubes have been used in military and commercial aviation for decades, due to the inability of conventional oils to operate in the temperature and pressure extremes of aircraft. "There has been little doubt that they [synthetics] offer superior lubrication and longer engine life, but are they worth the extra cost when the vehicle will be disposed of in 100,000 miles or so? The answer for most car and light truck owners has been a resounding 'no'. But suppose synthetics cost no more than conventional lubricants. Would you be interested then?"

Farlow does a great no-nonsense job of explaining the use of synthetic oils, by-pass filtration and oil analysis for safely extending oil drain intervals. "For the past 20 years or so, there's been a rumor that by using synthetic engine oil you could stretch oil changes to 25,000 miles. Many owners have played with the idea, but most get a bit chicken after a while and start worrying about their engines and go back to short changes of conventional oil. But a small group has been doing something else. They've been eliminating oil changes almost completely.

"Synthetics don't oxidize. Keep them clean, and they can be used for extremely long periods. How do you keep them clean? You can't reduce the filtration size of full-flow filters to less than 20 microns. But you can add another filtration system. It's called a bypass system, and it uses a filter that removes particles down to one micron or less . . . Synthetic engine oil can be used almost forever with such a system.

"Well, maybe. Even with the best of lubricants, some engine wear is going to occur. Also, there's always the possibility of something going wrong inside the engine. Maybe a copper bearing cracks or a small chip falls off or any of a thousand things go wrong. With conventional oil changes, these small particles are removed with the used oil, and you never know about them. With synthetics and no oil changes, they're removed by the filters, and you would still never know about them until something goes seriously wrong. Not to fear. There is an answer.

"Draw off a small sample of engine oil every 10,000 to 20,000 miles -- you set up the interval you're comfortable with -- and have it analyzed. The lab will send you back a thorough report showing the amounts of a wide variety of contaminants and a suggestion to either continue using the oil or replace it. Contrary to conventional procedure, you know what's happening inside your engine, and you never need to change oil until the lab finds a problem developing."

Farlow also mentions other synthetic lubricants. "Synthetic transmission lubricants are especially interesting because they not only decrease transmission temperatures but also withstand high temperatures much better than conventional fluids.

Does Farlow put his money where his mouth is? You bet. "I'm using AMSOIL's 15W-40 diesel synthetic and bypass filters in my latest truck Big Red. But Big Red isn't my first truck to get the AMSOIL treatment. I've used it since 1991 with excellent results."