On a '92 3.0 the coolant enters the water pump from the back via a tube which comes from the lower hose, traversingunder the intake manifold. In order to remove the tube to replace the O rings at either end, is there a small tube/nipple at the water pump end of the tube that must be unhooked? I see one in pics but can't find it visibly. Must the manifold be removed to do this repair?