Originally Posted By: dnewton3
BuickGN - I see the point you are trying to make, but I disagree on some level.
The "contaminants" can range widely in form and function. Coolant, fuel, dirt and soot are the main culprits. We'd probably agree on this.
No oil can really do much with fuel and coolant; once they get into the oil, they simply exist. Let's not confuse "coolant" with "moisture". Some amount of moisture is always present. The longer use cycles of an engine can help boil this out (technically, it's an evaporation process). But coolant and it's negative effects cannot be "handled" for too long by the host oil. Fuel does not really harm the oil, but it does dilute the oil, thereby reducing the oil's abilities. Further, moisture can be handled by the TBN of the oil add-pack; this is a direct relationship (the more TBN, the longer the oil can last in service to control the sulphuric acid, etc.).
Other issues are also intended to be controlled by the additive package. Soot and dirt (silicon) are able to be controlled by the dispersent portion of the package. Soot is basically the carbonized form of fuel from incomplete combustion. Dirt is typically ingested by the air intake process. These can be "held" in suspension by the anti-agglomerates, and thereby be kept at a size small enough to be harmless. Only AFTER that part of the add-pack becomes overwhelmed, does the soot and dirt start to co-join, thereby becoming large enough to become an issue. This is precisely why oil turns "black", but does no harm early on in the lifecycle of an oil. Because these items are controlled by the add-pack, the life-span of the oil is at least conceptually a direct relationship to the "robustness" of the add-pack. The more dispersants and detergents that are present, the longer the oil can perform. Your concept of dumping oil because these contaminants are building up is accumulating is sound, but I highly suspect your frequency is far too great. Premium oils should be able to last much longer than 5k miles.
So, in part I agree with you. If you have an engine that has a mechanical issue (leaking fuel injectors, intake filtration leak, coolant leak, etc) then dumping oil early and often can help control this problem and keep the oil health in a decent, manageble form.
But if your engine is in good shape mechanically, dumping oil (especially expensive PAOs) every 5k miles is simply a waste of good oil, because it's likely they are FAR MORE CAPABLE of extended duration due to higher base stock configuration and add-pack construction.
Also, I take exception your to comment that the only way to get rid of contaminants is to dump the oil. Bypass filtration can help control the dirt and soot for quite a long time. They cannot help with coolant and fuel. But again, this all comes down to how good of shape your equipment is in.
Equipment longevity is a result of "proper maintenance". Proper maintenance is perhaps best defined as a combination of your frequency of maintenance, product choices, and equipment condition.
You must tailor your inputs to control your outputs. There is no one perfect answer, as often times there is more than one road to the same destination. There are, however, "better" answers depending upon each individual scenario.
So, coming back full circle to the OPs post, "why not use HDEO in everything" if they are a "better" product over PCMOs? You certainly can. Though the question really is: "are you going to get your full value from it?"
You seem to infer that there are other reasons to use oil or change oil other than OCI, but I completely disagree with you here. "This thread is turning into an HDEO vs OCI. There are other reasons to run one besides OCI. HTHS comes to mind. More anti-wear additives are another."
What the heck good is "more anti-wear additives" if you don't use them all??? Why have "more" of anything if you never intend use it? At this point, you are admitting to paying for well more than you will consume. If you use HDEO because it has "more" of any characteristic, but you only use it to a level that can be satisfied by PCMO, then where in the world is the logic of doing that??????? It simply confounds me; there is no "logic" to this decision. You are operating soley on emotion; you "feel" that it's "better" even though there is no proof of it being so. Your comment about this being "HDEO vs OCI" is EXACTLY what this is about. You may have completely missed the boat in my previous post. There are mounds upon mounds of UOA evidence that show premium products do not do their job "better" (as defined by some level of "more at a single point in time"). They do the jobs LONGER. Show me any UOA where the wear-protection is 3x less by using a synthetic over a PCMO, that equates to the 3x higher cost, at some short or moderate OCI duration. Premium products, be they HDEO or syns, don't retard wear any "better" than a PCMO, UNTIL that PCMO is used up, thereby surpassing the PCMO.
That same concept goes for contamination control. If we assume the equipment is in good mechanical condition, then soot/dirt is going to be the major issue. I'm going to pick arbitrary numbers for the debate, so don't nit-pick. Let's say an engine produces 10ppm of soot for every 1k miles it travels. After 10k miles, it will have produced 100ppm of soot. If you use a PCMO that can safely handle 70ppm of soot, your oil will be capable up to 7k miles. If you use an HDEO that can handle 100ppm of soot, it's OK for 10k miles. If you use a syn that can handle 120ppm of soot, it's good for 12k miles. So, the premium products can last longer. But if you measure the soot load at 5k miles, it would have 50ppm of soot, REGARDLESS OF WHAT PRODUCCT IS IN THE SUMP! That is well within the capablility of all three products. The HDEO or syn CANNOT do a "better" job of controlling soot, because the presentation rate of the soot is constant. The premium products cannot control soot to a "better" level because even though they have "more" additive package, they cannot absorb the soot any faster than it is presented! The premium products cannot hasten the production of soot; they only can do the job longer! Get it?
OCI duration should be completely driven by one of two means.
1) arbitrary duration based upon some "guess" of ultra-conservative safety margin
2) data and planning.
Take your pick.
I couldn't agree more with you Sir! When I purchased my Superduty it was obvious that it had been poorly maintained, the oil was as black as the night. I changed the oil immediately and ran Delvac 1 5w40 and International filters for 10k. The UOA after the first oil change came back with great numbers, I did notice that the oil was still very black, regardless I stayed with this OCI for a while. Oil change after oil change I did notice that the oil was visibly cleaner and my UOA results had improved slightly. Under the advice of someone else on here, I ran my OCI's to 15k (I won't mention his name, but I will never understand the results as well as he does). The only issue that I have found with this OCI, is that the filter media becomes brittle and easy to tear. For this sole reason I will meet halfway at 12-13k. In regards to your point, I am still getting twice the distance out of my "expensive" oil Vs. the recommended OCI for my application, so it kinda pays off. Also I would like to add that my UOA results didn't differ much as to whether the oil was visibly dirty or not. I chose my oil for my application and known engine characteristics.
On a side note, International is now disregarding engine hours and mileage for OCI's on lease vehicles. The service intervals are now being dictated by gallons of fuel consumed. Which brings me back to the point you were making about contamination. We use Fleetgaurd filters and ESSO XD3 15w40.
