Block drain plug left side of engine is a puzzle

[ampa]

I'm wondering why this drain plug has a hose running from it, looks like a 1/4" braided hose much like the fuel lines, runs from the plug to a spigot on the bottom of the rad tank, this is an ISEKI 17 hp 3 cyl. diesel (G-174) I'm wishing to use this as a return from a circlating block heater I,m tryin' to install, the manual states nothing except that this plug is a block drain on the left side of the engine block if it has a purpose other than just a way of draining the cyl. block, if not I may have to install a "Y"connection and keeping it original, or can I just cap off the spigot on the lower rad tank, and use it only as a return to the cyl. block for my block heater....Thanks AMPA

 

[ampa]

All I need to know does this hose have a purpose, ? bein' connected from the block to the bottom rad tank Thanks AMPA

 

[ampa]

recieved no comments, so I gather I can plug the bottom rad 1/4 nipple and do way of it, .....Thanks Ampa

 

[mopacman]

it is their to drain the block when you drain the radeator