Death of an Engine

After getting all the repairs we knew about finished, Mags and I took the boat out for a shakedown cruise a few days ago. Without going into extensive details the engine block got really hot although the water temp and oil pressure gauges were reading good. Water was boiling out of the fresh water side of the heat exchanger so we stopped the engine and tried to sail.

Our short shakedown cruise - the double black course lines out and back

We had gone through the pass to the outside of Bocas del Toro. Seas were pretty large but the wind was down and a current was drifting us towards Isla Bastimentos. I checked oil and water/antifreeze and added a bit but they were not down badly. We restarted the engine and returned to Bocas Marina. Hot, hot, hot, hot!
Jeff the local diesel mechanic and I started it up a few days ago with the radiator/heat exchanger cap off and air was beltching out but the level of the water didn't drop so it wasn't just a vapour lock working its way out. Unfortunately, it was engine exhaust getting into the fresh water jacket and the engine got really hot really fast.

Our Pathfinder is not the first engine to die in Bocas, this big Worthington dates to the mid '30s

Normally I would pull the head and check the head gasket and head for blown gasket or cracks but this is an old, 1981 engine, that VW is no longer making and the marinizing company, Pathfinder is out of business. They had issues and therefore were not too popular. We managed to keep it going to here but now it would be good money after bad.
I have been checking the new Yanmar diesels and I can make the switch with a bit of work. But, even if the engine was here now, hurricane season would be on us before we could finish the swap and get to a really good hurricane hole. Bocas is below the normal hurricane paths so it makes sense to leave Kanilela here and return  in October when it is a little cooler. We can do the swap and then head out for next season in November.
Our immediate plans are up in the air but there are lots of options.
First, I will get the new engine ordered and prep the changes I will need to do for a new Yanmar. Why Yanmar? They are really popular with spare parts readily available around the world. 
We'll be in touch as I know more. Mags and I are disappointed not to be sailing but I had little confidence in the VW/Audi/Pathfinder after being let down numerous times so a reliable engine will be good.