Here is the air filter I had on my car when the last UOA was done that showed high silicon and iron wear.
It's a Wix 46116 filter, in use for 11,000 miles. The picture doesn't do justice to the dark black soot-like material coating the filter. I believe the black coating was from the disintegrating foam strip on the end of the air snorkel (to the right of the filter). A 1" piece of the "suspect" foam was also laying inside the air housing when I took out the filter. Anyway I also suspect that the air filter did not have a snug fit inside the housing either as the outside edge of the filter had a thin black coating. I rubbed some of it off with my thumb. Whether this was the source of my high silicon reading I really don't know, but I am suspicious. Anyway, everything got cleaned off, a new filter installed and I replaced the foam with some extra scrap pieces of Dynamat Dynaliner foam I had...made a cool foam repalcement by the way. Time and another uoa will tell if I found the root cause.
