How well does the typical mechanic recommend motor oil? Or another way to put it-how well does the typical mechanic know lubrication? I know of a lot of mechanics who recommend Valvoline oil, which does not seem to test at the top among people at this web site that have motor oils sent to labs. I remember when I owned a Toyota car and that dealership, at least, was in the process of changing from recommending Pennzoil oil to Valvoline oil. I have had mechanics tell me not to use Pennzoil or Quaker State, because 'they cause sludge in the engine.' Well, Quaker State has not been tested much by people at this site, but Pennzoil is the favorite of some at this web site. I know of only one mechanic who recommends Castrol (a woman mechanic in Santa Fe, NM), and Castrol seems to look good in testing. Another person who recommended Castrol to me was another woman working in a dealership Service Department. She let me know that Castrol was what she used in her own Saturn car, even though the dealership used Quaker State. Kind of a hint, huh? I would be welling to bet that none of the mechanics I know has even heard of Schaeffer's Oil.