Mobil 1 Question

[Tonyx]

I ran across this article recently which provide anecdotal evidence on why xx-40 weight is better for our turbo'ed XC70's. Copy/pasted here as I didn't want to hyperlink.
--------------------------------------------------------------------------------------------------------
Now, for the past few years, I've been running 5W30 Pennzoil synthetic, and Mobil 5W30 synthetic in the XC. All SM oil bought on sale when SN came out. My oil consumption on the XC (which now has 211,000 miles on it) has been a consistent 1QT every 1500-2000 miles. In other words, I am adding 3 to 4 qts between each 7500 mile oil change.

Well, the stash of cheap oil on my shelf has dwindled and about 2,000 miles ago, I used Castrol 0W40 in the XC (bought on sale, but available for a reasonable price here: https://www.amazon.com/Castrol-03101.../dp/B00JGQLZSU ). I checked the oil level before our trip to DC last weekend and after we returned. 2,200 miles after the oil change with the Castrol 0W40 - the oil level has move about 3/16" down the dipstick. About 1/4 of the way from full to minimum.

In other words, the oil consumption on the XC has dropped from 1 QT/2000 to about 1QT/8000!

Pretty dramatic difference. The T5 for the record, on its steady history of Mobil 1 0W40 uses about 1QT/8000. I rarely add oil before I change it, and then only to keep it near the top on a long road trip.

Needless to say, I am reconsidering the future oil changes on the XC and the next one won't be a 5W30 synthetic, it will be that Castrol 0W40 Synthetic.

[Ragman]

I would like to see the test results from the oil comparisons , if you have them? I've been using Amsoil for a few years now, transmission too, with excellent results. Curious to see the difference?

[mrbrian200]

There were several published tests I remember coming across this one is probably the most informative:
https://540ratblog.wordpress.com/

He ranks oils across several parameters, and by weight. For example brand x 10w40 may sit at the top for film strength but their 5w30 doesn't perform nearly as well, however, may be better with regard to thermal stability/high heat. I sifted through what was there for the best overall 5w30 (without additives) and decided Quaker State Ultimate looked the way to go. Mobile 1 isn't as stable under high heat (with Turbo this is probably more important). The new Pennzoil group 5 oils are ahead of the game with regard to thermal stability but not as good in film/shear strength. Amsoil weights he tested range between average to very good, but like I said, in the last 10 years others have caught up to and probably surpassed them. It was getting ridiculous over $80 for an oil change +filter using Amsoil. It was time to look at this again.