Quote:
Originally Posted by chris719
You’re correct overall, but pour point isn’t the figure of merit. The SAE winter rating is defined by MRV and CCS test results. If an oil passes CCS at -35 C it must be labeled a 0W, if it passes at -30 it must be a 5W. It’s about pumpability and resistance to gelation and cavitation. So, even though the pour point of M1 0W-40 is higher than PP Euro 5W-40, it will safely crank / pump lower. The old TWS 10W-60 had a pour point of -51 C but it won’t pass even 5W CCS/MRV tests. Pour point simply means the base stock has a lot of PAO / absence of wax formation. The winter grade is not optional, if it passes at 0W temperatures it must be labeled a 0W, etc. if something is sold as a 5W, it’s not passing at the 0W test temperatures.
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Thanks for the input chris!
Quick question, is ccs/mrv the baseline i.e. it passes at -35C it technically can go lower, the tests just cut off at -35?
Because technically there are places in Canada where -35 doesn't cut it, my area does get below -35 (before windchill is factored in) many times per year.