When you say 10mm, is that the head size or bolt size?
White is typically the color of factory teflon. Which you'd only find in a coolant jacket. The shoulder of the bolt makes it not a LIM bolt w/o question. Possible places you'd find this bolt are holding the passenger side engine mount into the head, maybe the SC belt tensioner held to the block. But the shoulder looks more engine mount than tensioner. or.. a timing cover bolt right below the outlet for the radiator hose and the other side at that same level on the engine.
