This is a pic of the head and the #5 spark plug. The culprit is the white thing circled in the middle, between the #4 and #5 spark plugs. What is it/its purpose? Kinda need to know since it's leaking like MAD. Is it a replaceable plug of some sort? Is there anything I can do to stop this thing from making a HUGE mess? Any help would be GREATLY appreciated since I have to take it on a 12 hour drive on Saturday up to Idaho. Thanks a lot!