Will 5W-20s soon be obselete?

[TiredTrucker]

The same thing is going on in the heavy diesel segment. 40 weights were the standard, but 30 weights are displacing them. Factory fills on all heavy truck diesels is 10w30 now. My factory reman 2000 Detroit 12.7L lives on 10w30. 845,000 miles on the reman now and just as good as when it was dropped in the truck. 10w30 CK-4 year round.

Personally, if I had a vehicle that called for a 20 weight, I would not stay awake nights worrying about it though I would probably use a 5w20 even if it called for a 0w20. I don't live in Fairbanks, AK.

 

[SR5]

If you look at this old Valvoline SynPower datasheet (here). The SynPower 0W20 has a Noack volatility of 12% while the SynPower 5W20 has a volatility of 10%.

This is the advantage of a 5W20 over a 0W20, given the same base oil and the same VII, then the 5W20 should be more shear stable and have lower volatility. IMO if you don't require the extra cold starting ability of the 0W20, then you are better served by a 5W20 which is more shear stable and less volatile (given the same blending and formulation).

I will admit, it's not always clear cut, as sometimes the 0W has more PAO than the 5W. So it's not always a like with like comparison.

Given that the cold cranking test (CCS) for a 5W oil is at -30C (-22 F) and for a 0W oil is at -35C ( -31 F), how many people here regularly start their car below -30C (-22 F) and don't use some form oil heating ? Sure some here do, but most? I would guess not.

 

[cheesepuffs]

SR5, great point about the cold cranking ability of 0W vs 5W. This is a mistake I myself am realizing I’ve made by switching to 0W and thinking it would benefit me at only say about 0 degrees F. Not really the case. 0W is hardly needed by anybody I’d reckon, in actual practice.