synthetic oils.

[dogfriend]

Originally Posted by mino54

, all you have to do is to read about lubricants for combustion engines, its not to tough to do.

What is it that you believe we should be aware of? Do you have a link?

Let's sum up the thread so far from my perspective:

You posted to inform us that Mobil 1 is not synthetic oil. You didn't tell us why you think we need to know that.

I posted to give you a link to Mobil's FAQ page which states that it is "100% synthetic oil". I suggested that you take it up with them.

Sheepdog posted to inquire why you believe that Mobil 1 isn't syn oil.

Hiremichaelreid posted a reference to a Wikipedia page that stated that Mobil 1 was changed to Group 3 base stock in 2001. Some people argue that it is no longer a "true synthetic". The Wikipedia page has been changed, so he quoted from a cached version.

I posted the current Wikipedia page which contains the statement I quoted that Group 3 base stock is now considered synthetic in North America. I also gave a link to a AMSOil page which gives an explanation about how the definition of synthetic oil was changed as the result of a court case between Castrol (who first started calliing Group 3 syn oil) vs. Mobil (who tried to prevent Castrol from calling Group 3 syn oil but lost the court case).

Fraser correctly pointed out that Wikipedia can be biased and should not be considered an authoritative source. He suggested lab testing is a better way to tell whether Mobil 1 is a "syn oil".

I agreed with Fraser and furthermore, I don't really think it matters what you call it, but Mobil 1 works very well in the Prius as verified by several members UOA results.

Sheepdog thought it would be cool if it were actually made from whale snot.

I wanted to point out that we should not harm whales to provide lubrication basestock.

You posted that we should read about lubrication theory. I have read lots on this both in engineering school and just for my own interest, but there are always new developments. What specifically should I read?

[tochatihu]

It is certainly possible that a Group IV poly alpha olefin oil (e.g., Amsoil, Pennzoil Platinum maybe? and the earlier Mobil 1) would have a longer service life in Prius than a Group III hydrocracked mineral oil (e.g., Mobil and Castrol current synthetics). We simply do not know. All of them seem to do an excellent job for 10 or 12k miles, maybe even longer.

I think it's reasonable that any of these oils will ultimately be limited by the exhaustion of the total base number additives, or some other secondary factor (water, soot), rather than viscosity change or some factor inherent to the base stock chemistry. Again, data are lacking.

Some Prius driver are running super long oil intervals (I define as >12k) but the used oil analyses have not been posted yet.

If ones wants to *always* change oil at short (5K) intervals, and doesn't mind varnish inside the engine, then high quality conventional mineral oils are inexpensive and probably adequate. If one wants to double the OCI and halve the waste oil production, then synthetic or 'synthetic' is probably the way to go. We don't think that they will leave varnish.

Double the OCI again, and reduce the waste oil to one-quarter? This remains an exploratory proposition.

[dogfriend]

Has anyone ever verified that Mobil 1 is now a Group 3 oil? I know that people have speculated that this is the case, but I haven't ever seen any authoritative proof that it is. I have seen this come up before on BITOG with some argument for and some against.

Mobil is kind of vague on the description:

Is Mobil 1 with SuperSyn Technology a fully synthetic motor oil?

Yes, it is. To meet the demanding requirements of today's specifications (and our customers' expectations), Mobil 1 with SuperSyn uses high-performance fluids, including polyalphaolefins (PAOs), along with a proprietary system of additives. Each Mobil 1 with SuperSyn viscosity grade uses a unique combination of synthetic fluids and selected additives in order to tailor the viscosity grade to its specific application