Bolt,not boat...
No bolt goes there. The oil leak is probably that vent hose. It looks to be leaking. Pretty normal stuff on these.I noticed the rear valve cover was leaking oil so I pulled the coolant reservoir off I noticed this hole in the valve cover. This might be a stupid question but the hole is threaded, so is there supposed to be a boat there or something else like I plug or something? I can't find any pictures of the top of the valve cover for reference.