Hi Mark, Searching the archives will not help they do exist it takes a 13mm socket to undo them, you may not be able to see them even with a lift, the bolck does hold quite a bit of fluid, I am guessing that you have the rest of the system drained or open run a hose thru the t-stat opening so you can get most of the old fluid out. you may e-mail me direct if you have further questions. Fareed