How to tell which dino oils are Group I or II

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Oct 22, 2003
By Detroit
I understand that Chevron dino oils are Group II basestock, but cannot get any information on Valvoline. Anybody know what basestock group is used in Valvoline Maxlife? Also interested in other brands of dino.

Best way I know is to look at the pour points and borderline pumping temps. If the PP of a 5w-30 is below -35F (below -30F for a 10w-30), chances are it's a Group II basestock. Noack volatility of the Group II stocks is also going to be lower,and they will have a Viscosity Index that is typically 10-15 points higher.

As a practical matter, the GF-3 and CI-4, diesel upgrades severely limited the use of Group I, solvent refined petroleum basestocks.

Group II's include:

Chevron Supreme
Pennzoil "purebase"
Petro Canada - some of these are actually Gp II/Gp III blends for an excellent price.
Castrol GTX
All the SAE 5w-20 oils - most of which also contain some Gp III stocks to help them pass the double length Sequence IIIF test.

I think the Chevron Supreme and Delo 400, 15w-40 are the best values out there, bar none. The Supreme not only has an excellent Group II stock, but a very nice additive package as well (borate ester and MoDTC). Delo 400 consistently show excellent oil analysis results and very low rates of oxidation.

I'd run the Supreme 5w-30 in the winter and the Delo 400, 15w-40 in the summer, if I was using a petroleum oil in a high performance, gas engine like my 1.8L, 225 Hp,Audi TT turbo ....

The "SAE 1007", 5w-30 reference lube, used as the baseline in Sequence IVB, Fuel Efficiency Test, is a non friction modified, petroleum oil. You could never get any petroleum oils to qualify for the starburst otherwise ....
Thanks TooSlick. The Chevron Supreme looks pretty good, but what about the starburst and Energy Conserving rating. I believe we still have an issue with temporary viscosity collapse in the bearings to achieve these ratings against the full synthetic 5w30 test oil. That's what scares me away from regular oils and into high mileage oils that don't do that. BTW, flash point of Valvoline 10w40 Maxlife is 242C--excellent and well above the Chevron 10w40 or even Delo 15w40. That really impresses me. I suspect Maxlife is Group II as it shows much higher flash points than the European synthetic blend Maxlife, knowing that in Europe they mostly are stuck using Group I mixed with Group III to achieve the required oil performance. But I cannot get Valvoline to tell me the basestock.

Oh yeah, I found an interesting article that, thought dated, indicates Conoco has Group II:
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