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.

It is important to note that the test results shown are specific to the packaged lubricants purchased by PQIA at one location on a given day. As such,  the test data for the brands shown should not be extended to other types and grades of the same brands, or the same types and grades purchased at other locations. Instead, these data only provide a snapshot of the particular sample.

SAE 5W-30

ALL BRANDS TESTED ARE LABELED  SM ILSAC GF-4

Click for data on the API SM 5W-30 brands tested

It is important to note that some of the locations PQIA randomly selected for sampling did not have 5W-30 engine oil available at the time of PQIA's visit. As a result, PQIA purchased and tested the most common grade available at the location.

SAE 10W-30

7-Eleven, SuperS, and Warren products are labeled SM ILSAC GF-4. PittPenn's label, however, does not specify the API service category. Instead, it reads "API USA"

Click for data on the API SM 10W-30 brands tested

The tests selected for the samples are 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 an 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.