I did a search on this and couldn't find any info... I did a Blackstone report on my engine oil, and I had a nickel reading of 5 (ppm?). The universal average for nickel is 1. What engine components are made of nickel? Blackstone, in the report summary, said that the reading is mildly high, but didn't make it sound like something I should worry about. I plan to do another oil test on my next batch of oil. Thanks for any info you all might have!