Quote:
Originally Posted by Red__Zed
Maybe I'm confused. I was under the impression that an SAE 5W-30 met the 5W low temp test, as well as the 30 weight 100C test, and behaved as in the following chart:
I know there's a lot of misinformation out there though, and I probably got some of it-- I won't pretend to know everything about oil. I am genuinely curious about how they rate the winter oils, if there is no standardized test. I was under the impression that the timed orifice method was used for the 100C test, and then it had to meet a standard at 40C, based on the cranking/pumping characteristics. |
In a perfect world they would want the oil to have the ideal properties of both, both the reality is that it is currently impossible. Trade offs have to be made at either end. Given that the oil spends most of its live at operating temperature they make a few more trade offs in the lower range.