Synthetic 004 Odds and Ends QUESTIONS TO MOBIL Claims are made that synthetic oil provides improved fuel economy because of reduced friction. There are no SAE or API specifications available that speak to the differences in friction between motor oils of the same viscosity. I was interested in discussing just what physical properties might be responsible for the reduced friction, so I made a call to the Mobil technical staff for the answers. I didn't get an answer that defined, in any technical sense, what those factors were. The answers I got were about tests made on fleets of trucks, etc. Well, of course we don't have any real means to verify those facts. Note that there is a difference between doubting the claims and verifying them. They did describe a test that I can verify. They pointed out that comparing the temperature of a closed gearbox using petroleum gear oil with the same gearbox using synthetic gear oil would indicate the differences in the friction of the two oils. It's strange how it all seems to come around. A failure in a differential because of excess heat is the mother of this whole investigation. After installing synthetic gear oil in the new differential, it does not even get warn under full load. HONDA? My bride and I own two Honda Accord autos. I stopped at the local dealership to inquire if they had synthetic oil available in connection with their service program. I was informed that not only did they not have it available. I was also advised that Honda said the long-term use of synthetic oil would shorten the life of the rear oil-seal and cause it to leak. That's pretty strong stuff. This was word of mouth stuff from the person who checks cars in for work. I turned to the Honda owner's manual. The official manual states that synthetic oil is suitable for use in my Honda Accord. Remember, Look to the Document. Reference to the Mobil web site Delvac 1 FAQs: The answer to Question 34 provides the following: "Delvac 1 is compatible with all engine seals and will not dry out or crack seal materials." A call to the Mobil technical phone line confirmed that both Delvac 1 and Mobil 1 are compatible with all engine seals. They say that synthetic oils may be incompatible with engine seals on engines manufactured before 1980. I feel certain that these discoveries do not apply to Mobil products alone, but to synthetic motor oils in general. The safest procedure is to consult the engine manual for any engine that you consider using synthetic motor oil in. That's what I did with my Cummins. Note that I did that with my Honda also, but I got information from an "unofficial" source that turned out to be unreliable. Check your sources carefully. SYNTHETIC FLOOD Walking past the shelves of the local WalMart demonstrated just how fast the number of full synthetic and synthetic blend motor oils is growing. There were more of these oils than petroleum based oils. All of these were rated API SJ, the current gasoline motor oil specification. Some were also rated API CF, which is the diesel motor oil specification for just a few years ago. Any of these oils rated API CF will work fine in diesel engines who's requirements do not exceed CF. But read the label because some do not have any diesel ratings at all. SYNTHETIC OIL AND ANALYSIS Since petroleum based oils and synthetic oils are formulated differently, their analysis must be done with different parameters. It is important to make sure the laboratory you send your samples to know just what oil you are using. If you are using synthetic blends, talk to the laboratory before you send them a sample to make sure they know enough about your particular synthetic blend to do the analysis. As reported in 003, the POA can handle full synthetic oils just fine by adjusting the meaning of the results. For example, the reading to change oil is 8 for synthetic oils, but 4.6 for petroleum based oils. I am not aware that any factors have been worked out for the POA when using synthetic blends. I suspect the factors will change depending on just what the proportions of the blend are. At least for the time, the best procedure is to use the factors for petroleum based oil with the blends. CaptnWil, Ret 40 Pier Pointe New Bern NC 28562 (252) 636-3601 captnwil@coastalnet.com

Hi Wil, Great report, I've really enjoyed it. I've got a couple of comments here that may help explain why synthetics have different friction characteristics or at least why Mobil doesn't exactly answer your question. ----- Original Message ----- From: Wil Andrews <captnwil@coastalnet.com> > Claims are made that synthetic oil provides improved fuel economy because of > reduced friction. I was interested in discussing just what physical properties > might be responsible for the reduced friction, so I made a call to the Mobil > technical staff for the answers. > > I didn't get an answer that defined, in any technical sense, what those > factors were. The answers I got were about tests made on fleets of trucks, > etc > Oil company technical types take a perverse pride in the fact that theirs is an "empirical science". They don't much care about the reason something works, just so long as it gets the desired result. A good example of this is tetra-ethyl-lead (anti-knock compound); Petroleum scientists can tell you, with great precision, what effect a given amount of TEL will have on any given refinery run of gasoline. What they cannot tell you is why it works - even after 80 years or so of experience. As to why synthetics have slightly better friction characteristics than mineral oils; It probably has to do with the molecular makeup of the two materials. I say "probably" because, as stated above, the people that design this stuff don't really care why it works. To save a bit of typing, let me excerpt a post I made 1-12-99 concerning the differences between synthetic and mineral oil: ******************************* First, a definition of terms: A mineral oil is one that comes out of the ground, is physically separated into component parts which are then re-mixed in whatever proportions are necessary to achieve the desired result. It follows that a mineral based engine oil is a mixture of two or more base stocks along with an additive package that, taken together lubricates, cools, inhibits corrosion, absorbs contamination, transports crud to the filter, neutralizes acids, and probably a few other things that don't immediately come to mind. A synthetic oil is any material that does an oil type job but doesn't fit the definition above and also isn't animal or vegetable in origin.The synthetic oil you buy for your boat or car engine belongs to a subset called "Synthesized Hydrocarbon Fluids" (SHF) chemically they are nearly identical to mineral oils. With SHF oils the manufacturing process is radically different; rather than physically separating and remixing a complex feedstock a simple feedstock (natural gas) is compounded with itself until the desired molecular weight and configuration is attained at which point an additive package is blended in. The outcome is that SHF oils are very consistent at the molecular level while mineral oils are a real hodge-podge. The benefits of this molecular uniformity are mostly restricted to extreme conditions, SHF oil performs far better than mineral oil at sub-zero temperatures and at very high temps as well but does not show much advantage under the operating conditions typically discussed on this list. ******************************* Another advantage that I didn't consider in that post has to do with the problem of molecules of widely varying size getting in each other's way as they flow through an engine (or gearbox). Because the molecules that make up a synthetic oil are more nearly uniform in size they don't interfere with each other as much. That results in lowered fluid friction and less heat. These are considered to be MINOR advantages at best by most of the people concerned with the formulation and marketing of these products. There are, of course other economy/temperature advantages that derive from making the oil thinner as in the 5w40 oil you cited in an earlier report. It's not uncommon for oil marketers to claim fuel economy improvements by switching to their product. Most often those claims are based on switching from 15w40 to 10w30. Improvements from replacing mineral 15w40 with synthetic 15w40 are predicted (by the people selling the synthetic product) to be much more modest. I really hope that you find a significant mileage improvement since such data would help us sell this stuff (demand for synthetics is flat and miniscule). > > HONDA? > In the interest of quote snipping let me summarize the conflict: Honda service writer says no to synthetics; Honda manual says yes to synthetics; Delvac 1 literature says it's safe for Honda. First, your owners manual was written when the car was designed and things change. The dealership gets a constant stream of updates as new information comes to light about any particular model car. Ergo, it's possible that he has some piece of info that you don't about seal compatibility. It's more likely, however, that the service writer has been encouraged to sell the "house brand" of oil. Another thing to consider is that there are different tiers of lubricant manufacturers. Major oil companies (Shell, Exxon, Mobil, etc.) are EXTREMELY conservative with the products that they send to market. The big guys also have the resources to thoroughly research all aspects of a new product (like how it works with Honda seals). Smaller companies are more aggressive in both formulation and marketing and at the same time are less able to do the little nit-picky bits of research (again, like Honda seals). All of this puts your Honda dealer in a difficult position: If FBN SuperSyn 10w30 has been shown to eat the seals out of the engine they obviously don't want you to use it. They also know that there are probably other companies marketing oils with similar formulations and they don't want you using those either. OTOH: Honda has determined that certain Mobil products are just fine. Catch 22 - There are legal issues with one company recommending the products of another in this context. What you end up with is blanket prohibitions against whole classes of products like synthetic oil. Bottom line: If a major oil company tells you something you can be assured that they know what they're talking about but you also have to be sure that you are asking the right questions. Cynically yours, Alex