LTHOUGH API CATEGORY SA OILS HAVE BEEN OBSOLETE since the 1940's, they can still be purchased in many discount and convenience stores. Marketers argue that the oils offer simple, inexpensive lubrication, but auto manufacturers want customers to be aware of the reiks of using obsolete oils, citing new evidence that SA oils aare "likely to cause serious damage" if used in engines built since the 1940's.

The Alliance of Automobile Manufacturers (AAM) recently released a report entitled "Impact of Low Quality Oils on Engine Wear and Sludge Deposits; A Comparison of API SA and API SL (ILSAC GF-3) Engine OIls." It reviews the results of two engine sequence tests run on both an API SA motor oil and an API SL motor oil. According to the report, the SA oil failed miserably in the areas of wear, sludge, and deposits.

According to Robert Stockwell of General Motors, the API SA oil failed in many areas and caused filter clogging. "When the pickup tube plugs, oil starvation will occur on startup and the engine will be destroyed," he said. "Further, the extreme scuffing indicated on five camshaft lobes in the SA test indicate that the life of this engine would be short, regardless of oil change interval."

The ASTM Sequence VG test measures sludge and deposits. Although the standard test time is 216 hours, the test for the SA oil was cut short at 168 hours because it had already clearly failed. Sludge deposits were evident on the valve decks, rocker arm covers and camshaft baffles at 144 hours, and kinematic viscosity had increased at 168 hours.

Citing the industry tests as proof that SA oils are harmful to modern engines, the AAM wants the lubricants industry to begin spreading the word to consumers. "The Alliance has asked API, The Independent Lubricant Manufacturers Association, Automotive Oil Change Association, NADA and other organizations whose members sell motor oil or interface with the public on lubricant quality issues, to help publicize this story," says Alliance staffer Ellen Shapiro. "In addition, the Alliance plans to post the study on its web site and discuss the issue with state regulatory officials."

The Alliance suggests that states can take action through new prohibitions, increased enforcement, new labeling requirements, and notices posted on store shelves.

The 12-page "Impact of Low Quality Oils on Engine Wear and Sludge Deposits; A Comparison of API SA and API SL (ILSAC GF-3) Engine OIls" study can be viewed in .PDF format on the Independent Lubricant Manufacturers Association's website: http://www.ilma.org/resources/impact_lowqualityoils.pdf.