Replacing lower radiator hose on an N52 egine

[ryushe]

After yet another slow coolant leak (already replaced a split tank, upper radiator hose, water pump, and thermostat earlier this year) I've come to the preliminary conclusion that this time it's the lower radiator hose or at least where it connects to the radiator, as there's fluid right below that point on the bottom cover plate. Space is limited insofar I only have a jack available, see below pic of when I replaced brakes two weeks ago

The hose is on order and should be here early next week, and includes the hose clamp.
Looking at it, it seems logical I need to do this from below. Anyone have a decent guide on how to replace it? Things to look out for? Other tips?

 

[raymond.harper]

Not the Z4 exactly, but the N52 engine. I would put newspaper or cardboard under your car when working, as you do make a mess of the concrete. A good trick is to put the wheel underneath the sill for safety.

 

[ryushe]

A good trick is to put the wheel underneath the sill for safety.

Yeah, it's on stands in that photo. I always use stands, and leave the jack just in case as well.

Thanks for the vid, I found that earlier, it does do a good job of glossing over the 'important' bits with regards to the actual hose.

Now I've heard there's a screw/valve on the lower side near the lower hose that will stop any flow of fluid, is this true? I.e. with that I should be able to replace the hose without having to drain the whole system, any truth to that?