Actually, your question is, basically, the one most asked, in one way or another, and is the basis for most all that we as AMSOIL dealers try to answer as the public in general has been so engrained with the concept that changing oil often is good and necessary, and changing even more often is better. Think about it. . . If everyone were to simply double their oil change interval from 3,000 miles to just 6,000 miles, the amount of oil sold would be cut in half. Lubricating oil, in essence, is a by-product of producing gasoline. From a barrel of crude oil, gasoline (and other fuels) is refined as the main product (there being no substitute, at least not yet) and everything else from lubricating oils down to the thickest of asphalts is a byproduct that must be gotten rid of. Therefore, the oil companies preach and advertise changing oil more and more.

The fact is that when you look at synthetic oils, they do not deteriorate like dinosaur based oils do, and their molecular structure, being formulated to be tighter and to have specific properties (unlike petroleum oil refining which simply separates out the base constituents into the different product categories) last longer and do the job better. When you think about it, although AMSOIL came out with the first API approved 100% synthetic oil back in 1972, every major oil company is now pushing a synthetic oil, seeing the writing on the walls!!! They don't necessary push it hard as they still have a main business to support, but they must be part of the pack to get the experience and marketing position for the future. You may be aware of the API SJ (ILSAC GF-2) category of oils that just came out late this past summer. The next generation of oils, GF-3, is expected to have such a level of performance requirements that the oil will have to be at least a blend of petroleum and synthetics to meet these requirements. This gives you a picture of why the oil companies are posturing as they are.

As for extended drains, even our diesel oil is only recommended initially as a 15,000 mile/1 year oil drain for most diesels. Some diesels, however, such as the Volvo VE D12, have a recommended change interval by the manufacturer of 25,000 miles. Mack, Cummins and others are likewise designing engines for extended drains as the truck fleets demand it! Our oil meets these manufacturer's requirements and can be used for these extended drains as the manufacturers build in better filtration.

Filtration is of the utmost importance to achieve more of a drain interval, coupled with oil analysis. Oil analysis determines the condition of the oil, and if you can determine that the oil, whether it is after 15,000 miles, 50,000 miles, or 100,000 miles, still meets the manufacturer's specifications for oil to be used in a particular engine, why change it???

Most oil filters filter only to 25 microns (one micron=.000039"). The finest tolerances in a typical engine is in the 5 micron range. AMSOIL's by-pass filters filter 98% efficient - one pass - at 3 microns. They will filter down to less than one micron, but at a much less efficiency rating. As a result, you are capturing dirt that will not only cause wear, but also keeping dirt out of the oil stream where it works to deteriorate the oil's additives. Changing the by-pass filters once per year (or every-other full flow filter change) typically keeps them working in top condition (but even if they get fully stuffed up, you aren't hurting the engine as you would still have the full flow filters). In addition, the AMSOIL by-pass filters hold water, which is a by-product of the combustion process. Water, mixed with other combustion by-products form acids and help deteriorate oils and additives.

As you stated, the oil cleans the engine, but the oil also acts as a conveyor of the dirt and other contaminants (metals, water, etc.) to the filter. If the filter can not remove the contaminants, or does not have the capacity (gets stuffed up and the by-pass valve clicks open and dirt is continuously circulated) then you have problems. But if the dirt is conveyed and held out of harms way, then the oil can do its principal job (lubrication) longer and the engine will last longer (less dirt in tolerances, smoother operation and better performance).

But the oil analysis is the key to extending drains past the base 15,000 miles/one year period. With oil analysis, I've seen people go over 200,000 miles without an oil change. You change full flow filters and by-pass filters, and the make-up oil sweetens the additives and helps keep the oil in spec. The oil remains within the manufacturers specification, proved by the analysis, and no warranties are effected. The oil analysis is actually better than a stack of receipts from cases and cases of oil!

As for the deposits, this is a typical oil company reference to synthetic oils where other oil manufacturers utilize the same additive packages as in their regular petroleum oil which is formulated for shorter oil change intervals. Once the additives have deteriorated and/or the oil filters have clogged, the circulation of dirt and acids cause the build-up around the rings, ring seal is compromised, and oil getting by the rings carbons up the upper cylinder area.

I contacted some oil companies awhile back and asked for specific specs in line with those which AMSOIL publishes. Look at the Technical Sheets page and download the oil that you would use. Then contact your oil supplier and get the same type of technical data (if you can!).

Note the pour points are much lower with AMSOIL and the Total Base Number (TBN), the index number indicating where the oil starts out with acid fighting additives, starts out much higher. Starting out higher, the oil is capable of staying up to spec longer (as the TBN deteriorates down to 4 +/-, or the oil analysis shows that the Total Acid Number surpasses the TBN, then the oil is "worn out" and its time for a change! Obviously, when an oil starts out with a TBN of 8, it gets to 4 quicker!

Also note the much higher volatility of the other oils. Volatility is the tendency to evaporate at higher temperatures. When the light molecules evaporate, the oil tends to get thicker. I'm sure you have seen how much thicker oil is when it is draining. Most people assume that is only from the dirt. A SAE Xw-40 oil will become a 50 or 60 grade oil. Oil "consumption" is often due to evaporation.

It is a fairly complicated process, and much of it just requires you to think about how the world is and who is telling you what. Most mechanics who preach 3000-mile/3 month oil changes were preached to by the oil supplier and the same television ads you read with the "pay me now or pay me later" lines. The only real way you will be convinced that you have been fleeced is the same way I convinced myself that big oil has been leading us down the prim-rose path, and that is by just trying AMSOIL. AMSOIL sells oil analysis kits and when you see how easy the engine starts in cold weather, and how the amount of wear is reduced (do an analysis on the oil you have in there now at 3,000 miles, then try AMSOIL and do one at 3,000 miles, or more, and see the difference) you will be convinced of the benefits.

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