What do these numbers mean?

sgmfan · Jan 4, 2003

Hi. I'm new here, as you probably know. FWIW, someone at the forums at taurus car club recommended your group.

I've been reading with great interest, particularly the recent thread about Shell Rotella Synth, since I've been using it for quite a while now.

I did a search, but I'm having trouble understanding the different groups of oil. What distinguishes I, II, III, and IV? (I think that's what you're calling them)

Thanks for the great site.

[ January 04, 2003, 11:01 PM: Message edited by: BOBISTHEOILGUY ]

G-MAN · Jan 4, 2003

Basically, Group I thru III are refined crude, with one exception. The main difference between Group I, II, and III is in the purity level and the VI (viscosity index). Group I oils are traditional solvent refined, and are the least pure, meaning they have more "nasties" like sulphur, etc. and less saturated parrifin molecules. Group II oils generally have the same VI range as Group I, but because of hydrocracking, isodewaxing, hydrofinishing (or a combination of all three), the purity level is higher as is the saturation. Group III oils are the purest and have the highest VI. Group IV oils are all PAO, the traditional base oil used for synthetics. Group V is the catch all category that contains all base oil types not included in the first four groups.

The one exception I mentioned above is Group III base oils that are wax isomerates. The feedstock for these oils is not refined crude, but is either slack wax (removed from distilled crude during solvent dewaxing) or waxy raffinate (generally a synthetic wax stream produced by the FT GTL process). This type of Group III base oil is the primary component of Shell's Rotella T Synthetic.

BOBISTHEOILGUY · Jan 4, 2003

Look at this and it will give you a more discriptive understanding on the different groups and base stocks.

http://www.bobistheoilguy.com/oilbasics/

digitaldrifter91 · Jan 4, 2003

i read ur page...alot of info, but its not sticking in my head. tell me then, im not a synthetic user..i prefer not to use it..thats group IV right? okie....so mobil drive clean is group......? should i go for group 2 or 3....can u please give an example of group one oil, 2, and 3 please...i really appreciate it. this is probably the only thing i dont know with oil.

my car, 91 accord 150k

thanks!!

ps...hehe i might jsut go back to penzoil

Giles · Jan 4, 2003

Here are some examples I know off the top of my head:

Group 1:
Quaker State
Penzoil?

Group III:
Castrol Syntec
Valvoline Synthetic

Group IV:
Mobil 1
Amsoil

Group IV Blends:
Mobil Drive Clean - 10% Group IV
Schaeffers

Maybe others can add to this.

G-MAN · Jan 4, 2003

quote:

Originally posted by Giles:
Here are some examples I know off the top of my head:

Group 1:
Quaker State
Penzoil?

Uh...not quite. Both Quaker State and Pennzoil use Group II exclusively. Pennzoil was one of the first to go totally to Group II for its multi grades and I noticed that even their straight 30 wt now has "PureBase" on the bottle, meaning it's Group II. Pennzoil and Quaker State synthetics are Group III, with the exception of their "European Formula" 5w40s, which are Group IV.

Giles · Jan 4, 2003

I read a MSDS for Quaker state that said it contained Solvent Processed Oil or something like that. I took that to mean Group I.

G-MAN · Jan 4, 2003

quote:

Originally posted by Giles:
I read a MSDS for Quaker state that said it contained Solvent Processed Oil or something like that. I took that to mean Group I.

That would be correct, and without seeing the actual MSDS, I can't comment further. Keep in mind that some oil companies still blend in a little Group I, even in their top tier oils. So, just because you happen to see the word "solvent" in the MSDS doesn't mean the finished product is a "Group I" based oil. For example, Shell's Rotella T Synthetic is primarily a Group III based oil (65%-75%), but has up to 3% Group I in the base oil blend.

BOBISTHEOILGUY · Jan 4, 2003

Ya missed ours...

Schaeffers uses group I. Obviously not in it's standard form as it has higher the 90% sat's and higher VI than standard group I. but none the less, its a group I.

Giles · Jan 4, 2003

XHVI, Thanks for clarifying about the blends and percentages. That makes sense. And since Schaeffers uses Group 1, I guess it isn't a given that it's inferior to have a percentage of Group 1 base included.

G-MAN · Jan 4, 2003

quote:

Originally posted by BOBISTHEOILGUY:
Ya missed ours...

Schaeffers uses group I. Obviously not in it's standard form as it has higher the 90% sat's and higher VI than standard group I. but none the less, its a group I.

Isn't it a little misleading to simply say that "Schaeffers uses group I" since they ALSO use Group II? The spec sheets for Micron Moly 5w30 and 10w30 state explicitly that Group II+ base oil is used. And the spec sheet for the 7000 5w30 says Group II is used along with PAO.

No doubt Schaeffers does use Group I in some of their oils. But they use Group II and Group II+ as well--especially in the conventional grades where Group II is the only cost effective way to meet the GF-3 specs.

dragboat · Jan 4, 2003

quote:

Originally posted by BOBISTHEOILGUY:
Ya missed ours...

Schaeffers uses group I. Obviously not in it's standard form as it has higher the 90% sat's and higher VI than standard group I. but none the less, its a group I.

Group I's stop at 88 percent saturation FWIW also

Here is a partial pull from the non blend 5/30 Micro moly SL GF-3 oil data sheet:

(Micron Moly® Engine Oil SAE 5W-30 is blended from the finest solvent refined, severely raffinate hydroconverted Group II Plus high viscosity index 100% paraffin base stocks available. These paraffin base stocks provide the Micron Moly® Engine Oil SAE 5W-30 with the following

Here is a partial MSDS of the 10/30 Supreme PAO Blend,that first CAS# is not a group I or a PAO CAS#

(100% Paraffin Base Oil CAS# 64742-54-7, 64742-65-0, CAS#64742-88-1)

[ January 05, 2003, 03:08 PM: Message edited by: dragboat ]

What do these numbers mean?

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