But What Do We Really Think? One of our jobs at
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always simple. We gather facts, examine and try the products, then make our recommendations based on disclosed fact.
With some products, the facts part is not so simple and the poster child for problem products is engine oils. There are two reasons for this. One is that readers want take-it-to-the-bank recommendations supported by unassailable testing and the other is that this testing isnt feasible. So every time we publish an article like Aprils report on oil additives and supplements, we get a trickle of letters like Jerry Johnsons (at right) asking what we really think.
Consistent with disclosed fact, we always tell you what we really think. With oils, the fact part is more difficult because all the manufacturers do expensive laboratory testing to prove lubricity, anti-wear and anti-corrosion characteristics of their oils. Weve done similar testing. But lab tests dont duplicate how oils behave in the real world and proving the correlation would require thousands of hours of testing in real engines of many kinds, in many climates and many types of flight operations. No one is doing that. If anyone is doing it, they havent published anything convincing, so the selection of oils becomes a best-we-can-do process. Consider the testing, apply what you know about oil and field reports and make your choice.
Based on this, when Im asked what I recommend or would use myself, I usually reply that any modern multi-grade oil is my universal choice. I like multi-grades because theyre technologically advanced, do a good job of staying in grade and obviate the need for seasonal oil changes, which many of us dont have time to fool with. Furthermore, I have personally tested the oft-repeated claim that single-grade oils “cling” better and thus protect more effectively against corrosion. I find the claim to be hogwash, frankly, and the oil companies say privately that they continue to produce single grades merely to satisfy customer preference. For those who care, single grades such as Aeroshell 100W are about a buck cheaper than the 15W50 multi-grade. If cheap really matters to you more than anything else, single-grade oils fit that design brief.
So when Im asked for my recommendation and based on my personal preference, its Phillip XC, a 20W50 multi-grade to which I add Camguard, bringing the effective price to about 75 cents more per quart than either Aeroshell 15W50 or Exxons Elite, both excellent oils in their own right. Id be happy with either of them, frankly.
My reasoning for the XC? For aircraft engines, which eat a lot of lead and have more blowby than auto engines, I prefer a mineral basestock, which has better solvent characteristics than the semi-synthetic basestocks used in the Shell and Exxon products. Second, Camguard gives a sliver of improved corrosion protection over the other products, although the difference isnt dramatic. Last, it has a seal conditioner to reduce oil weepage, which dried out our leaky TSIO-360 on the first oil change.
But if your experience suggests you can get the same performance from, say, a straight-grade oil with no additive package, I dont have convincing data to talk you out of it. And I wouldnt even try.
-Paul Bertorelli
