In an effort to assess where the bar is set for passenger car engine oil (PCEO), the Petroleum Quality Institute of America (PQIA) made the decision to test 10 brands of PCEO produced by major oil companies.  The results are in and the major brands tested look good.  

Ten brands of PCEO in quart bottles were purchased by PQIA at retail outlets in New Jersey.  Blind samples were prepared by PQIA and sent to Intertek Automotive Research in San Antonio, Texas for chemical and physical analysis. The tests selected for the samples were based on a combination of considerations.  Whereas PQIA is aware that (expensive) engine testing is required to determine if an oil meets a particular American Petroleum Institute (API) Service Classification, it also understands there are specific chemical and physical tests required to determine if an engine oil meets an API Service Classification. The bars for these tests are set by the API. And if engine oil does not meet the requirements of these tests, it does not meet the requirements of the designated API Service Category, regardless of how it performs on the engine tests. Tests PQIA looked at in this category include: 

• Viscosity @ 100ºC, cSt, (ASTM D445)
• Viscosity @ 40ºC, cSt, (ASTM D445)
• Viscosity @ -30ºC mPa s (cP) (ASTM D5293)
• Volatility, mass % loss, 1 hr, @ 250ºC (ASTM D5800
• Phosphorus,  ppm (ASTM D5185)

The second group of chemical and physical tests examined by PQIA includes others where, although there are no specific API requirements for the tests, the test data can be used to determine if a product is typical of what one would expect to see in a particular API service category. As an example, whereas the API does not specify a requirement for calcium, calcium is considered an integral and critical part of engine oil’s additive package. As such, an engine oil meeting an API SM Service Classification would typically contain calcium in the range of 1,600 to 2,400. This contrasts sharply with a typical API SA engine oil containing virtually no calcium.

And certainly if a lubricant manufacturer has independent  test data (bench or engine) that shows its lubricants offers higher quality and/or performance than others, we welcome this information and remain willing to publish it on this website if and when provided.

 Click here for data on the majors.

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