Group 1 vs Group 2 & 2+ base oil

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Jan 18, 2004
Shelby, NC
This whole oil thing is quite confusing. I understand (at least roughly) that the higher the group# the higher the quality of the oil (at least to a degree). Now my question is this, I like to use a syn blend in my Nissan 4x4 beacuse of short trips and small sump. I have used the Mobil DC Plus Blend and Syntec Blend, and am contemplating using Motorcraft 5w-30 since it seems to be a blend. The Mobil is supposedly a Group 1 base oil with PAO, the Syntec is Group 2 with Group 3, the Motorcraft is still a mystery to me; which is better in terms of absoute protection AND also for bang for the buck? This was much simpler back when I thought that Castrol was the best dino and was the end-all be-all of oils.
Crap! Middle age is getting to me, I forgot to ask the rest. Why would Mobil use Grp 1 with PAO? This seems to make no sense. Is there something magical
in this formulation that a Grp 2 plus PAO couldn't ? Would the Grp 2 base of the Syntec be better in the longrun even though it has Grp 3 as it's synthetic component? Is the Motorcraft Grp 2+ the best compromise of the bunch?
From what I've learned here, the group 1 oil is able to hold more additives than the other groups. I think some believe that the additive package is more important than the base oil used.
Group I base stocks are no more solvent-like than Group II or Group III base stocks regarding the amount of additive they can "hold". But, Group I base stocks need more viscosity index improver polymers to match the innate viscosity indeces of Group II and Group III base stocks, though, and may also need more detergent/dispersant additive to minimize the tendency to form sludge and varnishes (oxidative processes) than do Group II and Group III base stocks. Personally I'd rather use a brand known to rely on Group II base stocks (such as Pennzoil, Chevron Supreme, Havoline, Exxon Superflo, etc.) than a cheapie such as Coastal that likely starts out with solvent dewaxed Group I base stocks and then additizes it up the wazoo to reach a minimum performance point. In short, it's a given that ALL brands use additives, but the better formulations are able to trade additive quantity for quality to get where they wanna be with some assurance the oil will remain at the desired performance point for more than 3,000 or 4,000 miles. Funny thing is, Havoline (and Chevron Supreme when you can find it) are rather cheap to buy routinely, and so is Pennzoil and Exxon Superflo when they're on sale.

Originally posted by Ray H:
Group I base stocks are no more solvent-like than Group II or Group III base stocks ...

Actually, Group I does have more solvency than Group II and Group III. This was the primary reason that even fully PAO-based synthetics used Group I as an additve carrier before esterized additive packages were eventually developed.
Group I= detergency. That's why I thought they called it "Drive Clean"....

I know the basic performance characteristics of the oil don't look very good at all as far as flash point, etc.

Originally posted by csandste:
Group I= detergency. That's why I thought they called it "Drive Clean"....

Well, if you actually read what XOM said about the Drive Clean oil when it first came out, they stated that the oil had more calcium detergents in it than is typically found in other PCMOs, hence the added "cleaning" power of DC.
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