Some oils, such as Torco SR1 advertise that the conponents include "special polymers". Does anyone know what these are? In my mind, polymers suggest a kind of plastic. Does anyone know what the role of these polymers is in pcmos? As an aside, could these be responsible for motor oils such as motorcraft, which seem to have very little in the way of add pack in UOAs, having such excellent wear results? Thanks,
Polymers or viscosity index improvers - they allow the oil to have a viscosity spread, which means it can behave like a 10-weight oil when cold and like a 40-weight oil when hot, for example, giving you a 10w-40 oil.
quote: As an aside, could these be responsible for motor oils such as motorcraft, which seem to have very little in the way of add pack in UOAs, having such excellent wear results? Thanks,
No. Special ashless Friction Modifiers and GIII/V base oils take care of this. There is an extensive add package, you just can't detect it with a $25 VOA.
Polymers is simply a general term for a large molecule formed from smaller (monomers) molecules.
Specifically for engine oils, it refers to Viscosity Index Improvers.
Polyalkylmethyl Acrylates (PAMA) and Olefin copolmers (OCP's) are the two VII's used in engine oils.
Molakule, that is really food for thought. In purchasing Torco I was told that it was a g4/5 blend. Why would such a good blend be in need of VI improvers? Especially a 5w20? One would think that such a small spread wouldn't need much of the stuff . Thanks for the imput