API Classification For Engine Lubricant
API Classified Engine Lubricant Grades by Fuel
| “S” Service Oils for Gasoline (PETROL) | “C” Service Oils for Diesel |
|---|---|
| SA (Obsolete) | CA (Obsolete) |
| SB (Obsolete) | CB (Obsolete) |
| SC (1964) | CC (Obsolete) |
| SD (1968) | CD (Obsolete) |
| SE (1972) | CE (1983-Obsolete) |
| SF (1980) | CF (1985) |
| SG (1989) | CF-4 (1990) |
| SH (1994) | CG-4 (1994) |
| SJ (1997) | CH-4 (1998) |
| SL (2001) | CI-4 (2002) |
| SM (2004) | CI-4 PLUS (2004) |
| SN (2011) | CJ-4 (2007) |
API Classification For Base Oil
A quality of Lubricant Depend on Base Oil quality and dosage and quality of Additives. API has established base oil classification based on Physical and Chemical characteristics of Base stock.
Base Oil Categories
| Category | % Saturate | % Sulfur | VI |
|---|---|---|---|
| Group 1 | <90 | >0.03 | 80 and <120 |
| Group 2 | >90 | <0.03 | 80 and <120 |
| Group 3 | >90 | <0.03 | >120 |
| Group 4 | PolyAlfaOlefins (PAO) All Other Base stocks Not included in Group 1 to Group 4 | ||
| Group 5 | |||
Percentage Of Saturates :
Unsaturated hydrocarbons found in crude must be removed or converted in to more stable, Saturated molecules to Improve Oxidative Stability and Decrease sludge formation.
Level Of Sulfur :
Sulfur is considered an impurity that is removed in refining. It may be undesirable a it can affect performance and It may affect vehicular emission when burned.
Viscosity Index :
This measurement indication the relative change in viscosity with temperature change. Higher viscosity index are preferable. The higher number the less an oil thins at high temperatures and thickens at low temperatures.