Long thread but worth reading, some for the information presented, some to see how adamant folks can be about not wanting to consider an alternate view.
As someone in the Tungsten Disulphide business, I am always interested in opinions such as those presented at BITOG regarding oil and grease additives in their various forms. As far as Liqui-Moly of Germany, they are a very good company, and in many surveys, the most well known brand in Germany.
Yes LM offers two MoS2 fortified oils, and their MoS2 fortified engine treatment. No, the MoS2 fortified blends are not accepted or endorsed by the OEM's, as no OEM will probably ever willingly endorse solid insoluble particulate materials for introduction in their oils. The MoS2 used by LM is a solid particulate form of average particle size less than 0.3 micron which allows it to remain suspended in oil due to it's relatively low mass and high surface area at that size. Additionally it will not have problems with filtration at that size.
While they are not specifically endorsed by any OEM, that does not mean that solid particulates have not been tested and accepted internally by OEMs, just that they will not willing offer that acceptance in a non OEM product.
For example, and sorry that I cannot cite specifics due to NDAs, but every one of the "Big 3" has utilized MoS2 or WS2 solid film coatings in their engines at some time or another. One example is cited here: http://subscriptions.sae.org/content/970009/
on the use of solid film on the piston skirts. These have been typically spray coated or plasma deposited coatings on a variety of parts such as Piston Skirts, various Bearings & Bushings, and (Sure to draw flame from the engine break-in purists) Piston Rings.
In almost every case studies were done because these are sacrificial wear coatings, and when they wear, the coating goes into........ that's right into the oil. Every one of the Big 3 has studied these solid particulates extensively and concluded that there are no negative effects, and in some of the cases noted that the beneficial affects warranted leaving the excess powders on the parts in the case of impingement spray, or thicker layers in the case of deposition to allow for some extra material in the oil.
Now in a standard spray coating of WS2 the average particle size is 0.5 microns. The typical average size of MoS2 is 1-3 microns but can be processed down to 0.3 and lower as needed. So how does that compare to an OEM's acceptable level of oil contaminants? Typical filtration is in the what 10-15 micron effective range if I am not too far off.
So an OEM appears to be fine with filtration that will allow solid contaminants of let's say carbon at 8 microns to wander around the engine, and yes it will probably get filtered eventually. Not the best lubricant in the engine would you say, but proven solid lubricant particulates in the sub micron size range as utilized by LM is a concern?
Again I am asking if you truly believe that a 0.3 micron particle of MoS2, that is less than 1/25th the size of that 8 micron bit of abrasive carbon that is acceptable to the OEMs, is to be considered unacceptable? Sure, get some user that dumps 2 pounds of MoS2 into their Prius engine, there are going to be problems. But used as directed by a competent manufacturer and are you really going to stand by the argument that a solid form of Moly is bad whereas a soluble form is ok?
Now I make a few assumptions here, one is that the particles are actually sub micron and from a reliable source. Two would be that the MoS2 is of high quality because as a mined material, it is subject to the geological conditions under which is formed. Three is that if the solid particulate is in an oil, that the oil blend conforms otherwise to all specifications needed for the vehicle, and if it is a treatment, then the carrier must not interfere with the oil it is being added to.
I surely hope that the folks here do not contend that MoS2 is not a lubricant as that would be ridiculous.
It is worth noting that MoS2 much like WS2 coats almost all of the internal surfaces that it comes in contact with which is one reason a first time treatment will result in more MoS2 coming out of the oil. I have read numerous times that it only coats friction surfaces which is simply not the case. The plus side is that both MoS2 and WS2 will actively hold a film of oil on the surfaces they have coated providing a layer of oil on cold start, as well as providing a corrosion resistant layer when an engine is stored for a prolonged time.
The next technological step in solid lubricants was to drop into the true Nano sizes below 0.1 micron as this increases the surface area and reactivity. In the Nano sizes even WS2, which has about 50% more mass than MoS2, will stay in suspension without a separate dispersant. Nano WS2 is available commercially in products such as Miller's Oil products, or some of Archoil's treatments. Nano MoS2 may or may not ever see commercial product as it is easier to suspend due to it's lower mass.
So that was a few thoughts to add to this discussion, and a question or two about the validity of OEMs views on, and acceptance of, particulate lubricants in an engine. Hope it was not a total waste of your time to read, and I will try to find time to stay more current in the forums.