coolant line broke, is it necessary, need some help asap.

[chlubb]

There is a 1/4" hose coming from the drivers side of the coolant expansion tank that goes to a small nipple connection on the drivers side top of the radiator. For some reason, the nipple cracked and then broke off and i lost all the coolant. I have tried to JBweld the nipple back on and it worked momentarilly however it began to leak again.
THis seems to be an overflow return line although I cant find any diagram for it.
I clamped the line and drove it for quite a while yesterday with no ill effects.

Can anyone verify that this is a non essential line? My next step is to determine if I can find a plumbing fitting, threaded on one end, with a nipple on the other to JBweld into place as a permanent replacement, there is no way I am going to get a new radiator for this.

Any thoughts would be great.
Thanks,
Chris
2000 ML320