I installed mine today, took can apart first to make sure I could, found it was very tight, O ring jammed crooked, so corrected before mounting so it is hand-tight firm. I believe I will be able to reach in and spin it off by hand now.
My intake hose also touches the head, thanks for tip Stun a.
Had to go buy an 18 mm deep socket today, could not believe I did not have one, but nothing else works. $10 for one socket made me cringe. Sunday afternoon you take what you can find.