Quote:
Originally Posted by ChrisSlicks
Because it isn't an SAE-5 oil, it is an oil blend. A 5W30 isn't going to perform the same as a SAE-5 or an SAE-30, most of the time it is somewhere in between. It's properties are such that it can pass the minimum test for SAE-30, however there actually isn't any standardized test for Winter weight and most oils certainly wouldn't pass the test of SAE-5.
The viscosity numbers quoted (60 cSt @ 100F) is an average from actual manufacturer test data. On a cold start on a cold day it will be slightly higher, probably around 80-90.
|
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.