Quote Originally Posted by JDNSW View Post
The other source of silicon in the engine is dirty workshop procedures, adding dirt with the oil or when checking the level!
I think think might happen quite a lot John, in both professional and user serviced engines.

I've also heard of contaminated oil from the bottling plant, again poor procedures. This wasn't one of the majors but a premium boutique oil quite a few years ago, confirmed in a virgin test of the leftovers in the bottles.
The analyst suggested a pretty standard, off the shelf oil and the high silicon + wear metal numbers immediately and substantially improved.