DPF-Burdened Diesel Engines Are Fighting a Fuel-Contaminated-Oil Battle and LOSING !
It’s Time to Armor-Up Your Turbodiesel with AMSOIL.
At 4% fuel dilution, AMSOIL delivered. The competition failed.
Diesel fuel is a natural solvent, and quickly reduces the motor oil’s life expectancy and effectiveness. In diesel engine oil, a fuel dilution rate of 2 percent is abnormal and anything over 5 percent is excessive. Fuel dilution leads to reduced oil viscosity, reduced oil film strength, increased engine wear (particularly in the cylinder/ring area), increased volatility, weakened lubricant detergency, accelerated lubricant oxidation, varnish formation, acid formation/corrosion and low oil pressure.
Factors such as frequent starts, excessive idling, short trips and cold starts have contributed to moderate levels of fuel dilution in diesel applications for years. But recent issues created by modern Diesel Particulate Filters (DPF’s) and other emissions management strategies have brought the fuel dilution problem to a whole new level. For example, increasing fuel dilution levels are documented in 2007+ Caterpillar C13 and C15 on-highway engines.
In addition, the DPF regeneration process in 2007 to present GM, Ford and Dodge diesel pickups has also been identified as a major cause of troubling levels of fuel dilution. Except for the 2011+ LML Duramax engines, all 2007+ OEM engines employ an “active” regeneration strategy that includes in-cylinder injection of raw diesel fuel during the piston’s exhaust stroke. Some of the fuel is wiped/washed past the rings and directly into the crankcase, diluting the oil. This periodic washing of raw fuel into the oil makes it even more prone to viscosity loss and places the engine at greater risk of abnormal wear.
AMSOIL’s premium CJ-4 Synthetic Diesel Oils stay within viscosity grade, even when diluted with 4% fuel – which has now become common in some vehicle conditions. Even though no oil can provide a decrease in your oil-dilution rates from regeneration over-fueling, AMSOIL CAN and DID provide superior protection for higher levels of fuel dilution than was previously encountered in normal diesel engine operation. AMSOIL’s engineers understand the huge negative impact of fuel dilution problems on engine longevity due to DPF active-regeneration (as noted in the leading paragraph), so they made sure that AMSOIL’s diesel oils continue to maintain viscosity and other essential properties at higher fuel dilution rates, long after other oils have failed.
(Published in 2009, the G2752 test report was archived due to one or more oils being reformulated, so that the performance results may have become inaccurate for revised formulations. However, the DPF active-regen fuel-in-oil problem is very real in diesel engines, especially when the truck is primarily a non-loaded commuter or idles extensively. The report still illustrates AMSOIL’s history of superior lubricant engineering that provides a much wider margin of performance above minimum OEM requirements, which deliver valuable advantages under unexpectedly adverse conditions, preserving the life of your engine, transmission, differential. Click link to open full G2752 test report in a new tab.)
(Brian Dobben – former OEM Headquarters Senior Engineer)
For detailed model-specific info on DPF engine oil fuel contamination, and other insider engineering tips for Dodge RAM, Ford, GMC and Chevrolet turbodiesel pickups…
VISIT YOUR SPECIAL RAM – FORD – GMC DIESEL OWNERS PAGES:
Is There A Risk of Gasket Leaks or Seal Leaks When Changing to Synthetic Oils?
A former OEM headquarters senior engineer gives detailed answers to common questions about potential engine oil leaks when changing to synthetic oils.
Can a change to synthetic engine oil cause gasket or seal leaks? First, let’s summarize. The short answer is no: that is a myth. However, gaskets and oil-seals are two entirely different things. Gasket leaks are never caused by engine oil. But under certain circumstances synthetic oil can more clearly reveal an existing oil-seal leak, sometimes called a “false seal”. A far more common result of changing to a true synthetic motor oil is to eliminate oil-seal leaks. In fact, AMSOIL synthetics are rigorously designed to be not only compatible, but even MORE beneficial to seal materials than conventional oils. So will changing to a true synthetic oil more likely help you, or, cause problems? If you understand what’s happening and what to look for, you can usually know whether you have a rare case with genuine risk of having an oil leak problem, or whether you can just be another thrilled customer who discovered the secret of AMSOIL. Below, we’ll uncover the realities so that you can decide for yourself.
Gaskets are the easier subject, so let’s address them first.
Synthetic motor oils cause gasket failure? (LOL, no, not in this solar system!)
A gasket is not the same as a “seal”, although it does provide an engine sealing function. A gasket is a thin material placed between two smooth component surfaces, which get strongly and evenly clamped together by bolts or screws. By design, OEM engine gasket materials are impervious to all standard motor oils (Group I, II, III, and IV). Gasket leaks are caused by mechanical damage to either the gasket or the clamping/sealing surfaces, by improper assembly or improper gasket selection, by loose or damaged bolts, or by high-compression engine modifications (to increase horsepower).
A few years ago, a respected ASE-certified mechanic recommended to one of my brothers that he should not change his recent-model Cadillac over to synthetic because there was visible indication of very slight “seepage” at a gasket, and that if he installed a synthetic it could cause gaskets to fail – “and a head gasket failure is an expensive repair”. I shared this with an automotive engineer at GM headquarters, the OEM who designs and makes Cadillacs. His response nearly dripped with derision: “What does using a synthetic have to do with a head gasket failure!?! I’d like to hear the logic behind that one!”
Similar wild stories are widespread, shared by “experts” who may or may not be well-intentioned. Typically the anti-synthetic stories seem to be rooted in either the petroleum oil companies anti-synthetic propaganda years ago (before introducing their own “synthetic”), or from a well-intentioned mechanic who mis-diagnosed the cause of a customer vehicle’s problem. (I personally know one of these mechanics. He’s respected in his tiny country-town community – population under 500 – but he has no interest in logically discussing obvious weaknesses in his conclusions.)
However, other motives for bashing synthetics can occur when a mechanic has been paid to work on an engine. Perhaps he has created a small oil leak by not following good practice with gasket installation, or by using cheap replacement gaskets which do not meet the OEM design requirements for that engine application. In such cases, the mechanic may not want the owner to change to a synthetic oil which might result in a more obvious leak which he would be responsible to repair. Or perhaps he feels that there is a leak risk from his poor workmanship, such as not replacing torque-to-yield (TTY) bolts as required in order to have proper gasket-clamping force. In such a case, he might give a caution about synthetics so that he can later blame the use of synthetic oils if a gasket leak develops.
[However, a few synthetics on the market are Group V: esters can chemically attack some plastics, and some seal or gasket materials including RTV. This issue has likely contributed to the belief that synthetics can cause oil seals or gaskets to leak. RTV is sometimes used in aftermarket shop work in place of a sealing gasket, or combined with a gasket either to help hold the gasket in position during tricky installations, or to ensure sealing of a damaged or re-used gasket. Since AMSOIL does not use Group V base-stocks, AMSOIL synthetic engine and gear oils are fully compatible with all standard gasket and seal materials.]
Weak-gasket failures are relatively rare. But a weak gasket may exist from a manufacturing flaw, for example, or from a borderline engine or gasket design, from damage during the original engine assembly or during engine repair work, or from overpressure caused by engine modifications. A weak gasket can fail at any time. But just because that failure occurs a few days/months after changing oil brands does not mean that the oil had anything to do with it. That’s called “pure coincidence”.
I once had a valve-cover gasket that leaked oil, and after I changed the engine over to AMSOIL it leaked even more. When I removed the valve cover, I discovered that the valve cover had been removed before and that the flat machined sealing surface of the engine had been gouged in that spot: the gouge was a leak-path which had nothing to do with the type of engine oil, but was cleaned out by the synthetic so that it could leak more. By cleaning the gouge, and simply adding a gel gasket-sealant in the nick area before replacing the gasket, I minimized the leak to a very low level that didn’t cause problems.
What about oil-seals with Synthetic Engine Oils?
First, do you actually have an oil leak now? This is important because if there is no leak, there is no concern when changing to a high performance Group IV (PAO) synthetic, or even a pretender Group III petroleum “synthetic”. The reality in summary? If there are no oil-drips in the driveway, and if inspection under the vehicle, in the engine compartment and on top of the engine does not show any surfaces wet with oil, then for all practical purposes you have no oil leak to worry about: changing to an AMSOIL synthetic engine oil is risk-free, and nothing but huge advantages. In fact, true synthetic oils are one of the three biggest secrets in automotive maintenance.
[Caution: see Q&A below for the one exception to synthetic oil compatibility – Group V ester synthetics. This caution does not apply to AMSOIL products.]
Further below we’ll define oil-seal leaks in more detail, but first you need a simple background on oil-seals. Most oil-seals are essentially round pliable rings (made of an elastomer material) which seal around a shaft hole, keeping the oil inside the engine while allowing the shaft to move. For example, valves slide back and forth inside valve seals, and crankshafts rotate inside the seals. A “main seal”, “front main seal”, or “rear main seal” usually refer to seals around the main engine crankshaft which transfers all the rotational power, created by the pistons, out of the engine and into the transmission and wheels.
When an engine runs with petroleum oil, the sludge and varnish deposits that occur (from using petroleum oil in the hot engine) will accumulate around your pistons, rings, seals, valvetrain, and in oil passages. These deposits on a seal will block the seal material’s access to the engine oil, causing the seal to very slowly shrink and harden from engine heat. Ironically the same deposits can eventually help to seal older engine seals from the oil leaks which the deposits have caused. This type of “sealing” from petroleum oil deposits is a sign of invisibly growing problems such as piston ring sticking, sludge deposits in valve covers, oil passages and oil pans which can lead to decreased oil pump capacity output and restriction of critical oil galley passageways over an extended period of time, plus many other issues.
Key point: Most oil-seal elastomers are not designed to function isolated from oil. In fact, most oil seals need continuous oil contact, and are designed to benefit from oil washing in two ways: from cooling effect, and from seal-conditioners in the oil’s additive package. So these petroleum varnish and sludge deposits are definitely detrimental to the proper function and longevity of your engine. Removing those deposits and preventing reoccurence is important for long life of every engine, including its oil seals.
Reality? A good synthetic motor oil is ideal rehabilitation for shrunken seals, and can maintain healthy seals almost indefinitely. For example, because AMSOIL Synthetic oils are rich with top-quality cleansing detergents, and do not break down to form deposits, these engine oils are able to clean out the engine to restore normal, healthy function and prevent serious further deterioration that often occurs from petroleum oil buildup. These benefits occur throughout the engine, from piston rings to oil passages and oil seals.
The Million Mile Van is a good example: it ran standard oils for the first 68,000 miles of its life, and ran the rest of the million miles with AMSOIL synthetic engine oil. It never had an oil leak
You may have heard the myth that synthetics cause engine seals to leak. Good Group IV (PAO) synthetic motor oils absolutely do not cause seals to leak, but they may more clearly reveal an existing leak path, caused by petroleum oil deposits, due typically to one (or both) of two conditions:
a failed seal which is in need of mechanical replacement, or
a shrunken seal
[See Q&A below for the exception to synthetic oil compatibility with engine seals: Group V (ester) synthetics. This caution does not apply to AMSOIL products. There are only a few Group V synthetics on the market.]
Let’s review each condition.
A failed seal is because either the seal lip is worn down, or the seal is hardened and cracked from old age and heat exposure. (But again, most of this deterioration is caused by the seal being isolated from the motor oil, due to sludge and varnish buildup.) In reality, the “worn down seal lip” is usually more shrunken than it is worn, meaning that rejuvenation is likely able to restore proper sealing. It is true that if you have an antique engine (over 25 years old), and the seals are original, the seal design is usually not as good as modern engines: old seal materials were more prone to cracking when shrunken and hot. In such cases, although the presence of oil-wet surfaces might mean that you have a cracked seal, the greater problem is that there are likely damaging levels of internal oil sludge and/or varnish which need to be removed in order to preserve the remaining engine life.
A shrunken seal condition is more likely if you have a ten-year “old” engine that has been running petroleum oil for several years. If, for example, it leaks around the rear-main oil seal, then chances are it will initially leak more with a change to a true synthetic oil. But that synthetic oil change is typically the beginning of better engine health, not the end of the seal’s life or of the engine. What do I mean by that? Our engineering answers to these reader’s questions nicely illustrate what most often happens in these situations:
Q: What about my leaking main seal (for engine oil)?
A: If it is “seeping” oil slightly, that typically means that it’s got deposits on the other side that are keeping the seal-conditioners in the oil from getting to it, and so it’s drying out and shrinking.
I had that problem – a classic one – on my ’94 Taurus SHO (Super High Output) with the Yamaha 3.2L engine. It was leaking enough to keep the bottom of the engine and transmission wet with oil, and occasionally put a drop or two on the driveway, with 60,000 miles on it. Now, “everyone” in the national SHO Registry owner’s club seemed to agree that you MUST replace that leaking Yamaha seal, including the top American mechanics who are recognized SHO experts. Because, they said, there was no other option, and it would just continue to get worse. But I didn’t change the seal. Instead, after researching the subject more, I just changed to AMSOIL’s 5W-30 (ASL) because I knew it would probably help. And in the first couple thousand miles, it leaked more. (Right on par, as I expected, due to cleaning the deposits out from around the other side of the seal.) Then over about 5,000 miles that oil leak got smaller and smaller. After 10,000 miles you could barely tell there was a leak. (Typical results of AMSOIL’s superior seal-conditioning performance.) By the time my SHO had 80,000 miles on it, the underside looked like there might have been an oil leak sometime, or maybe one starting, but you sure couldn’t tell where. That was exciting, and impressive, and it saved me a lot of money. The rear main seal leak was gone – it was cured by AMSOIL engine oil. And ~100,000 miles later when I sold it, it still wasn’t leaking.
Q: “I’m concerned. I have a lot of miles on my engine, and some people say don’t change to synthetics with high mileage. Can you explain about Cracked or Leaking Seals in more detail?” A: There has been a lot of fear-selling of seal & gasket-leaks in the market, mostly originating from petroleum companies and quick-change oil franchises who get maximum profit from consumers NOT using the superior synthetic oil technologies. It’s interesting that when a vehicle is new, “they” say that you don’t want to change to a synthetic because of warranty (fear)… and when it’s out of warranty you don’t want to change because now your engine has “higher mileage” and it might (gasp!) develop “problems” if you use synthetics. It’s pure consumer manipulation: a psychological pickpocketing scam. Fear is a powerful marketing technique, especially when it’s aimed at keeping you locked into familiar habits with safe, familiar results: it’s easy to tap the fear of unknown risks.
In order to move past baseless fears and discuss the realities to consider, we first need to answer a basic question:
What is “an oil leak”?
An oil leak is NOT a slight discoloration. If you have a discoloration around a seal or gasket, that is NOT a leak. Unless you have a show-vehicle that will be judged in competition and you are bothered because it won’t clean or it reappears after you clean it, you would be crazy to even think about “repairing” that. Discoloration spots like this can occur from a single drop or smudge of oil from outside the engine, and this is a common result of normal oil-level checks (a drop or two from the dipstick) and oil changes: when the engine is being refilled with oil, anyone in a hurry or who doesn’t frequently change oil will typically spill a little oil somewhere into the engine compartment, and oil that isn’t completely cleaned up can be blown around in the engine compartment when the engine starts and the fan and belts are turning.
Discolorations never turn into leaks because you change to a high-quality true Group IV synthetic oil, like AMSOIL.
When there is slight seepage of oil around a seal, which is common from shrunken seals, it is not a reason for worry when converting to AMSOIL, but is actually a good warning sign that you SHOULD SWITCH to an AMSOIL synthetic engine oil: after a likely period of slightly more seepage, AMSOIL’s rejuvenating reconditioning of the seal will restore proper function, and the leak will gradually diminish to less than originally. Eventually, it may completely disappear. This can take up to 15,000 miles depending on the seal material and the condition of the seal. But in our experience, leaks are usually reduced to below pre-AMSOIL levels by the time it’s driven 7,000 miles.
A true engine oil leak is when an engine surface and/or underbody surface area is always wet with oil. Then the important question is this: where is it leaking from, and how much is it leaking? If it’s leaking enough to get a large engine surface wet with oil, but it is not dripping in the driveway, or if it leaves a drip every day or two, this is typical of a shrunken and/or worn seal condition. If you can watch consecutive drips on the driveway, leaving a growing spot, you better check your dipstick weekly because THAT is when you are more likely to have a cracked seal or some other mechanical problem. IF you have a cracked seal, then anything different that you do with your oil can cause much faster leaking, and we DO NOT recommend that you change to a synthetic oil. Instead, have a mechanic look at the engine to identify the problem and quote a repair: then change to a synthetic after you have repaired the problem, in order to prevent more internal engine damage.
There is some slight risk on old engines with high mileage on petroleum oils, that an oil seal is cracked from being extremely dried out, and is being mostly “sealed” with sludge deposits. Some feel that because this low risk exists, that they should not switch to AMSOIL Synthetic Engine Oil because a cracked seal will “begin to leak” a lot more. (But if it is not leaking now, then it is probably not cracked!) However, it is these deposits which are often the primary cause of seal wear and cracking, because they prevent the oil from cooling the seal and prevent the oil’s seal conditioners from keeping the seal soft and lubricated.
Our opinion, as automotive engineers, is that when a slight seal-leak condition exists, it often indicates a high level of sludge and varnish deposits in the engine which are decreasing engine life, and as they continue to build up they are accelerating engine wear and creating an ever-higher risk of rapid or sudden engine failure. It’s similar to the risk of cholesterol deposits closing off your arteries and causing heart attacks under stress conditions.
If a small oil leak turns into a bad oil leak immediately after changing to AMSOIL, it is likely that the AMSOIL has revealed a cracked seal. But if a cracked seal leaks badly after switching to AMSOIL, and you have to replace it, it’s also an indication that you’ve dramatically extended your engine life by switching to AMSOIL. And that’s great! No-one wants the expense of replacing a seal, but it’s a problem that will only get worse, and it’s cheaper to replace a seal than to replace the engine!
See more recent Q&A e-mails below, from exchanges with our engineering staff:
REALITY CHECK – Summary on Seal and Gasket Compatibility:
AMSOIL synthetic motor oils are made of completely pure, ideally designed synthetic base-stocks, blended with the highest-performance additives available, and are fully compatible with all engine gaskets and seal materials. In fact, because they are more painstakingly designed than petroleum oils, AMSOIL synthetic oils help maintain seal integrity better, rejuvenate shrunken seals, and extend seal life far better than conventional oils. However, AMSOIL Synthetic Motor Oils are recommended for use in mechanically sound engines! Most “leaks” are slight seepage that does not drip oil and is only significant in car-show judging. If you have a vehicle that is actually leaking oil badly, then it may be best to repair the seal prior to converting to AMSOIL. And it’s a smart move to replace that seal and switch to AMSOIL – seal problems often indicate high levels of internal engine deposits, and replacing the seals is a lot cheaper than replacing the engine.
Only you or your mechanic can investigate and determine your engine condition and the type of oil leak that may be present in your vehicle engine. Because of this, there is no way that Ultimate Synthetic Oil or AMSOIL can guarantee leak-free oil seal or gasket integrity of your engine after changing to AMSOIL. But this information should better equip you to interpret what you see or are told, and make an informed decision about whether you should change to a synthetic oil.
These e-mailed/posted questions were answered by our degreed automotive engineers.
(None of them are employed by AMSOIL, Inc.)
E-mail Comment: I was researching synthetic engine oils online. These claims (see below) would indicate that Amsoil is actually not the best option for synthetic oil, as it is not esther based. Your thoughts appreciated.
Glenn J. June, 2016
A: Glenn – I really appreciate your question, and the quotations you provided. They make me think that I should modify/enhance the content on a couple of my pages. Those quotes are essentially broad-sweeping “news-bite” generalizations across all synthetic oils from all manufacturers. As such, they provide no details, nor do they explain numerous caveats, or assumptions underlying certain statements, or exceptions, or downsides. Further, they are likely slanted to a specific type of application, and/or a specific brand. As you’ll see below, the omission of certain key information points toward the likely category/group of the original information source. I have tackled each comment section below [as bracketed italic comments to the specific statements being made]. These, of course, are my own opinions/perspectives as an automotive engineer and studied AMSOIL dealer – not in any way an official AMSOIL perspective.
I’m also going to add this to a website post about seal and gasket compatibility, because it can be important for people to realize these differences about synthetic oils.
Not all synthetic oils are equal [This is very true.] Some give better protection and last longer than others, depending on whether they’re formulated with Ester or PolyAlphaOlefin (PAO) stock. Synthetic oils made from the ester class are much more expensive, but are more durable and hold up under hotter temperatures. [This is true as a generality, but does not account for the specific PAO molecular structural design, nor the type of ester. Nor does it put the “hotter temperatures” into perspective in actual application use: there is no value in holding up under hotter temperatures, for example, if the PAO oil does not see temperatures beyond its endurance limit in that actual engine application.]
Synthetic oils have different base stocks, which comprise some 90% of the oil. [Again, a generality, which can in reality vary from 75% to nearly 95%, depending on many factors.] The base stock is the actual lubricant The other 10% or so is the additive package. The relative ability of oils to lubricate is determined by the components of the base stock. There are two principal classes of base stocks used in real synthetic oils: synthesized hydrocarbons (PAOs) and organic esters. [As explained below, these are classed in the lubrication industry as Group IV and Group V oils, respectively.]
The base stock materials used today many popular synthetic oils are made of carbon and hydrogen molecules. These are synthesized from ethylene gas molecules into PolyAlphaOleflns (PAO). Almost all the synthetic oils sold in the stores are made with PAO base stocks. PAOs provide better viscosity characteristics, are more resistant to oxidation and have much better low operating properties than petroleum oils. [Good so far: those generalities are accurate except to note that PAO’s can be created starting from a number of different types of feed-stock.] PAOs are cheaper synthetic oil base stocks, [they CAN be, but not neccessarily]and aren’t as durable as the ester class of synthetic oils.
[Those last eleven words are an overly broad generality with a lot of exceptions and caveats. As I alluded above, “durability” is tied closely to temperature, but also to other factors. In fact, the durability of a PAO in a car or truck engine is most closely tied to the design and uniformity of its actual molecular structure – there is quite a bit of variation on this in the market, so that the differences are best measured in the results of the standardized ASTM tests that the entire oil industry and OEM’s use for development and testing of oils. Further, the esters (Group V) are a broad category with a considerable number of variations. The REALITY is that a well-designed and uniform PAO structure is going to hold up well enough in the vast majority of applications that the durability of the additive package, with the synergy of all its components, is a greater limiting concern than the base stock – which hints at why AMSOIL’s test results are, overall, better than any other oil, while delivering longer drain intervals than any other oil on the market. It takes exceptional expertise and committed, determined business decisions supporting excellence of performance, to deliver an oil with both a robust high-performance base-stock, and a robust high-performance additive package.]
Some of the popular brands of PAO oils include Amsoil and Mobil-1. These are known as a Group IV oil.
Organic esters are made by reacting certain acids with alcohols, forming acid esters. There are alcohol diesters and Polyol esters. [Each of these two categories represent many, many variants.] This process uses expensive materials and results in lubricants that cost many times more than PAOs. [Another overly broad statement – the truth is that the cost ranges overlap, and both Group IV and V oils have relatively cheaper or more expensive types/designs.] Only esters are durable enough to withstand the rigors of jet engine operation [I believe that is true, though I’ve never dabbled in jet engine lubrication, and THAT is where the issue of very high operating temperatures becomes paramount in base-stock oil performance] and they are used in racing and high performance cars. [True, but it goes both ways, and a more accurate generalization is that PAO’s are more used in racing and high-performance cars and trucks far more often than esters.] These oils can cost $8 dollars or more a quart. [This statement dates the information to roughly 8-15 years ago.] Redline is an example of an ester synthetic oil. These are known as a Group V oil.
Additionally, Glenn, there are two very important issues which are not “addressed” in those statements, although perhaps the better word is “disclosed”:
Seal compatibility and gasket compatibility are an important difference between Group IV and V base-stocks: Group IV oils are fully compatible with OEM seal and gasket materials, while Group V are NOT compatible with many of them. This issue is one reason why “synthetics” have a reputation for causing seal and gasket leaks… and it is an issue that I need to address in a revision to my blog article on seal and gasket leaks. In racing engines that use Group V oils, the engine builders are using seal and gasket kits that are compatible with the different and more chemically aggressive nature of Group V oils.
Toxicity is seldom mentioned or discussed in consumer literature that favors Group V oils, but it is a very real downside to Group V oils. Toxicity and seal compatibility are the two reasons why AMSOIL does not use Group V base-stocks. Instead, AMSOIL has focused their efforts on getting PAO’s to perform at or above ester levels – other than the higher temperature range of esters which is actually not needed in automotive combustion engines.
Also, remember that “the devil is in the details”. In fact, either good or bad can be hiding in the unspoken, undisclosed details. For example, a little bit of an ester can go a long way in enhancing certain performance aspects to equal or approach that of a full-ester base-stock… yet at a low level it would have little impact on toxicity or seal compatibility, and would just be considered part of the additive package… it would affect the tested performance, but not the classification of the base stock oil.
Since “durability” is a shapeless, relative, undefined term unless it’s given specific context, let’s get specific in the real world: How long or how many miles does an oil stay within all required performance specifications for a new oil?
There is a powerful reason that AMSOIL’s Signature Series Synthetic engine oils are the only ones on the market rated for 15,000 miles / 1 year severe duty service, and 25,000 miles / 1 year under “normal” service conditions. Ponder this carefully:
AMSOIL engine oils are carefully engineered to perform at such a high world-class level that they are guaranteed to still reliably continue to meet good design performance standards at these long mileage intervals. If other motor oils are, actually, more durable or robust than AMSOIL, then why are shorter drain intervals recommended, and why is their performance not guaranteed for longer drain intervals?
I trust this is helpful. And again, thank you very much for the insightful question, Glenn !
Brian Dobben – BSMET
Automotive Engineer, Lubrication Specialist
Former Senior Engineer – Chrysler/Dodge/RAM/Jeep/Fiat headquarters
LeTourneau University Alumni
AMSOIL University Alumni
Society of Manufacturing Engineering
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