What Are the Key Criteria for Choosing Engine Oils?

When selecting engine oil for an internal combustion engine, it is crucial to consider the specific technical characteristics of that engine. To determine the right oil, lubricant manufacturers evaluate engines based on three primary criteria. These three essential factors are as follows: Viscosity grade  2. Performance level  3. OEM approval (Original Equipment Manufacturer approval). Beyond these, additional supporting factors—such as base oil quality, ash content, viscosity index, pour point, volatility, and fuel economy—are also taken into account.

The viscosity grade is defined according to the standards set by the Society of Automotive Engineers (SAE). (SAE J300)

Several international automotive organizations and authorities establish classifications that determine oil performance levels. These may be;

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

In addition, many well-known global vehicle manufacturers (OEMs) publish their own specifications and testing methods to classify engine oils according to their internal quality requirements.