I dropped the coolant vent plug bolt when bleeding the rad! I cannot for the life of me find the spec of that bolt so that I can replace it. Ford wants to sell me the entire assembly for over 100 bucks! I really just need the spec for that bolt so I can be on my way. If anyone could measure the bolt or recommend one from https://www.fastenal.com or some other common hardware store I'd really appreciate it. 3.9L V6 engine. Here is a thumbnail and I've uploaded the big view. Thank you all very much.