Specific tests are developed by oil manufacturing companies, engine manufacturers and specialized technical organizations to specify the quality and maintain industry standards for lubricating oils.

The American Petroleum Institute (API) classification system is a method of classifying engine oils according to their performance, characteristics and relating this to their intended type of service, generally considered the standard.

Other organizations such as the Saudi Arabian Standards Organization (SASO), Association of European Automotive Manufacturers (ACEA) and the Japanese Auto Engineers Association are also referred to for classification.

Under guidelines from these organizations the performance of different grades of oils under different conditions and temperatures are tested, evaluated and classified.

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