On Sun, 27 Jan 2013 13:45:45 +0000 (UTC), Tegger
wrote:

wrote in news:a949g8p7fatqaffk23cq48p5vnfoqn6q7v@
4ax.com:


2 minutes would likely be safe. 5 would definitely be pushing your
luck.




Even 30-seconds is not safe if there is no coolant in the head. The rad
being missing is NOT the same as simply having low coolant-level in a
complete system.

Combustion temperatures are around 1,500-2,000 degrees F. That heat builds
in seconds if it can't be carried away; without coolant, the surrounding
metal will overheat /very/ quickly, creating the strong probability of the
head warping, which will cause head-gasket failure and poor valve sealing.


I don't know but my hunch is you are correct. That said since this
newsgroup seems indecisive about exact amount of time (understandable
IMO), I think he is well advised not to take a chance because I
think?? he has more to lose than to gain. Of course ultimately he
will make that decision.