Just went out and checked a 5qt container of Mobil 1 which was
purchased inside of two weeks ago. Still marked "Tri-Synthetic".
That is their old stock, SJ rated oils.
I'd be interested to hear if anyone has detected a similar change
in Mobil Delvac 1, or in the Caterpillar synthetic diesel oil which is
reportedly put together using the Delvac 1 basestock plus an
even tougher additive package.
I have not seen any change on Delvac 1. But the Delvac 1300 Super has been cheapened up in base stocks. It has the smilar deteriation in pour point, etc.
If Shell would cut some volume discounts, I'd be happy to give
their Rotella synthetic a whirl. I'll have to write them as well.
Or the Chevron 5W-40 synthetic (CH-4 rated).