Originally Posted By: Shannow
Originally Posted By: Gene K
The reason it was introduced as a 5W20 was it "acted" like a 10W30 in the bearings. To me that means high HT/HS.
Since the natural HT/HS of a SAE20 is similar to a 10W30 it made me suspect it might have been VII free.
I'm confident that it was.
I'm searching for the truth, but really DO believe that was how it was built...yes it was a 5W, yes, it had KV in the 20 range, but all of this pre-dated HTHS in J300.
Shell in Oz had XMO, which was a 15W30 XHVI oil, which also I believe was a monograde.
Closest I've been able to find on anything viscometric is this paper on testing the "new" 5W20 synthetic against an SAE 30 in a volvo.
EPA website
Download it and read it, and see how it affects your opinion...I don't want to sway one way or the other.
Thanks. Cant say it convinces me, one way or the other. Interesting anyway/
PS I thought Mobil 1 was introduced in '74 but if it was '76 i stand corrected.