The engine's characteristics are considered in selecting engine lubricant for internal combustion engines. Lubricant manufacturers apply three key criteria in producing the oil suitable for the relevant machine. These three key selection criteria are as follows:
In addition, additional criteria (base oil quality, ash rate, viscosity index, pour point, evaporation loss, fuel economy, etc.) are also important.
The viscosity class is defined based on the norms of the SAE (Society of Automotive Engineers). (SAE J300)
There are some automotive associations and authorities that determine Performance Levels. These are as follows;
Apart from all these, some globally known vehicle manufacturers (OEM) establish their specifications and classify engine lubricants with their test methods.