Perhaps not pulling over when the coolant light is flashing is some kind of
subconscious way of saying you want to do that engine swap. :)

Of my coolant leaks, I suspect one of them was caused by me working on the
engine - pinhole leak.  The other two caused by a bad cap.

My similar tale is seeing the temp rise after a 15km traffic crawl on
a Canadian highway (cause by mudslide)...  OH WE ARE CLOSE, I SAID, ONLY
50M TO THE END OF THIS TRAFFIC MESS.   about 20M to the end it went POP
HISS.  kids ask, "will we have to sleep here?", mom says "well the tow
truck won't make it through this traffic mess".  everyone starts crying!
  seconds later thunder and lightning start.  giant scraping sounds of
diggers clearing the highway.  oh formative memories!  (we poured whatever
water we had back into the system - it was the coolant sensor that
exploded) and limped along.  Very thankful VW coolant sensors are common
parts ($5 + $70 cab ride) and we were back on the road the next morning.

...and drove on another 2000km on that trip.

Tom