Base oils are grouped into 5 classes:Group I Solvent Neutral HVI stocksGroup II Hydrocracked / Hydroprocessed HVI stocksGroup III Severely Hydrocracked / Hydrop
BASE OIL CLASSIFICATIONS
Base oils are grouped into 5 classes:
Group I Solvent Neutral HVI stocks
Group II Hydrocracked / Hydroprocessed HVI stocks
Group III Severely Hydrocracked / Hydroprocessed VHVI stocks
Group IV All PAO’s
Group V All others not included in Group I,II,III or IV
With each increasing group classification, more and more intense processing is involved. The result is a higher quality, but more expensive base oil.