What are the Selection Criteria for Engine Lubricants?

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:

  1. Viscosity class
  2. Performance level
  3. OEM approval (Approval of the Original Equipment Manufacturer)

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;

  • API: American Petroleum Institute
  • ACEA: European Automobile Manufacturers' Association
  • JASO: Japanese Automotive Standards Organization
  • ILSAC: International Lubricant Standardization and Approval Committee

Apart from all these, some globally known vehicle manufacturers (OEM) establish their specifications and classify engine lubricants with their test methods.