Several years ago, I drove my '84 1,200 miles, with a cracked head that
was putting a lot of exhaust gas into the coolant, by cracking open the
bleed screw in the radiator.  I had to pull over and add coolant every
25 to 30 miles but it didn't overheat.  I drove until I got the flashing
light indicating a low level in the expansion tank.  Then, while revving
the engine, I filled the tank, replaced the cap, let the engine go back
to idle and I was on my way for another leg.  Yes, it was the trip from
hell but I got it home where I could unload the family and all my stuff
and start the disassembly and the ordering of parts.

Before I tried the loose bleed screw it would form a big air bubble and
overheating because of it.

Sometimes you just have to do whatever works at the time.

Mike