This new Mobil oil formulation appears to be causing quite a few discussions on other car forums. If you look at the before and after specs on the 5W-30, the temperature maximums and pour ratings are not as good on the "new" stuff. I found the last of the old "SJ" rated 5W-30 at a local store last night. By the time I need to buy it again, there will be more info and analysis about this. I hope Exxon/Mobil hasn't ruined an oil I have completely trusted.
A month ago I was in Kragen seeking Mobil 1 10-30 for another vehicle.
They were out, but I noticed Chevron had a full synthetic, so I grabbed it.
I remember some years ago reading an API report on motor oil tests. It seemed in most important categories for conventional oil, Chevron and Castrol were fairly consistently very high on the list for most categories compared to at least a half dozen other brands.
Especially in viscosity stability and flash point. Low on ash level too.
I have yet to pull a data sheet on the latest Chevron offering. But it might be an interesting compare with Mobil 1. I will see if I can find it.
Many more years ago, more than I care to remember, I was renting a house from a Mobil engineer in Washington state. This was maybe a couple of years after Mobil had introduced a synthetic (with a conventional oil carrier). He told me, that although Mobil is only the 5 th largest (back then) they put a greater percentage of profit back into research than any other petroleum company.
Sometime later I found an article in the Wall St. Journal that supported his assertion.
However, we are hardly dealing wtih the same Mobil as the flying pegasus days (anybody remember the pegasus kites the stations carried?) Wow, really dating myself now!
Anyway, some comparisons may be in order. I am sure it is still a superior oil compared to the best conventionals, though some will argue if it needs to be even that good for the use it will find in most vehicles. Myself, the extra price is not bad (when discounted) for the added margin of protection.