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ISO Cleanliness | Viscosity Chart | Base Oil Definitions |
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API Base Oil Definitions
Group I base stocks contain less than 90 percent saturates and/or greater than .03 percent sulfur and have viscosity index greater than or equal to 80 and less than 120.
Group II base stocks contain greater than or equal to 90 percent saturates and less than or equal to .03 percent sulfur and have viscosity index greater than or equal to 80 and less than 120.
Group III base stocks contain greater than or equal to 90 percent saturates and less than or equal to .03 percent sulfur and have viscosity index greater than or equal to 120.
Group IV base stocks are polyalphaolefins (PAO).
Group V base stocks include all other base stocks not included in Group I, II, III, IV.