All V engines I've had have the block drains on both sides. I don't think it can be completely drained by just one. However the great majority can be drained by removing the one plug you can see, plus drain the radiator. I sure wouldn't be pulling off parts to get to the second drain. In fact I agree with post above, just drain/change what you get get by draining radiator. Use Ford Gold coolant concentrate(or G05) and distilled water. If you're not getting the entire amount changed, change it more frequently. If the coolant is actually rusty or dirty it may take a few drain and fills. But I doubt it is in bad shape.
