What is inferior about Group III's?

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2,480
Other than Pour Points which are higher...probably because of the low temp. performance abilities of Group IV PAO's...what other shortcomings of Group III's are there? We know it's not long intervals...aka. BMW Long-Life synthetic (group III)...so what else if wrong with them?
 
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I don't think it's so much an issue of what's wrong with Group III. The better way to look at is the "good, better, best" model. Group II is good, Group III is better, and Group IV is best when measured against industry standard criteria like volatility, etc. Group IIIs can come close to PAO in these areas, but I've never seen a single publication where they equal or match PAO. Plus, with the exception of wax isomerate Group IIIs, PAOs will have a higher natural VI and MUCH lower pour points. If you throw COST into the mix, that can change things somewhat—but usually not for the consumer. Group IIIs cost the manufacturer less than PAO, but you rarely see that savings passed on to the consumer. If it were, one advantage to Group III motor oils would be that you could get PAO-like performance at a lower price. But since most companies price their Group III oils within a few cents of Mobil 1, that just isn't the case.
 

Patman

Staff member
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Oakville, Ontario
I don't think group 3 oils hold their viscosity as well as real synthetics. I've seen 10w30 Syntec shear back to a 20wt for instance, something a 10w30 synthetic should not do (in the cases I've seen, fuel dilution was not an issue either, and it sheared back in less than 3k)
 
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quote:
Originally posted by Patman: I don't think group 3 oils hold their viscosity as well as real synthetics. I've seen 10w30 Syntec shear back to a 20wt for instance, something a 10w30 synthetic should not do (in the cases I've seen, fuel dilution was not an issue either, and it sheared back in less than 3k)
Yes, but this could be the fault of inferior VI improver and not the base oil.
 
I have been using Castrol Syntec 5w-50 since 1995 and recently posted a lab test. From what I have been reading it is not as good as Mobil 1. I have been thinking about switching after my supply of Syntec is gone, got it for $10.00 a gallon two years ago. In my lab test from Blackstone it did not shear back but thickened, why does that happen.
 
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quote:
Originally posted by V6 Diesel: I have been using Castrol Syntec 5w-50 since 1995 and recently posted a lab test. From what I have been reading it is not as good as Mobil 1. I have been thinking about switching after my supply of Syntec is gone, got it for $10.00 a gallon two years ago. In my lab test from Blackstone it did not shear back but thickened, why does that happen.
Excessive oxidation can cause the oil to thicken.
 
Excessive oxidation can cause the oil to thicken. To see if I am on the right track, my oil is getting too hot? It has been driven in cold weather but on the highway at speeds up to 80mph for up to 400 miles per trip. And is a better grade of synthetic more resistant to this?
 
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SC
quote:
Originally posted by V6 Diesel: Excessive oxidation can cause the oil to thicken. To see if I am on the right track, my oil is getting too hot? It has been driven in cold weather but on the highway at speeds up to 80mph for up to 400 miles per trip. And is a better grade of synthetic more resistant to this?
Several things can contribute to excessive oxidation. A PAO based oil will be more resistent to oxidation than a Group II or Group III based oil.
 

MolaKule

Staff member
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Iowegia - USA
In most dinos, the more volatile components (the lighter viscosity components) will boil off and leave behind the thicker componenets, resulting in a thicker oil. The oxidation of VII's also results in a thicker oil. I think you will see, because of economics, new lube products coming to the market with mixes of Group III, Group IV (PAO), and more exotic esters (Group V), abeit in smaller amounts.
 
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Location
Oklahoma
quote:
Originally posted by Patman: I don't think group 3 oils hold their viscosity as well as real synthetics. I've seen 10w30 Syntec shear back to a 20wt for instance, something a 10w30 synthetic should not do (in the cases I've seen, fuel dilution was not an issue either, and it sheared back in less than 3k)
It appears though many of the GF-3 EC ,SL X-30 wts are shearing though. I too beleive some very good Group III's with some Ester will soon be available to us. Now if the price is right I would go for them if they perform. I see Castrol has a new 5/40 Syntec. I would be interested in learning more about that oil
 
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Retired | Wausau, WI
You can get the Syntec 5W40 at most VW dealers. That use to be the only place you could get it, however I read somewhere that they were going to start selling it retail to the consumers. It is a Group III oil.
 
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Location
Oklahoma
quote:
Originally posted by Dr. T: Where did you see the Syntec 5-40?
At a Castrol Distributor that also distributes Exxon/Mobil Products,,,I can get a deal on the Exxon /Mobil stuff because they do. The Syntec 5/40 evidently does not come at bargain ,even to them. I expect it to cost more at retail than the others based only by a phone conversation yesterday . Time will tell. [ February 05, 2003, 08:29 AM: Message edited by: dragboat ]
 
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Clarksville, Tennessee
Way back when, I used the syntec in my F150, that was before I knew better. As I can't see paying $$$$ for a conventional oil as compared to a syntnetic that is far superior in oxidation, stability, and cold weather performance. Now there is some good points to a Group III oil. From what I understand, they work better with some addtives, also they are less expensive to process than a Group IV/V oil. Therefore the price should be reflected accordingly. For instance if you could get a top quality Group III designed for extended drains of 10,000+ for say $2.95/qt. That would be good value and performance for a passenger car/diesel truck. I wouldn't use if for a high performance engine, that is raced or turns high temps(like a turbo, or supercharged engine) I feel that it is more suseptable to cokeing. Anyhow, I would like to see a decent blend of Group III/IV/V at an attractive price. As long as they promised that they use no less than a Group III!!!! Back to the syntec, I have seen some decent analysis on the 5w40 that was run 10,000 miles in a VW Jetta. As this is what is recommended in the Owners Manual, both the oil and the drain interval. You can do a search for it on the tdiclub site.
 
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