I see a lot of bongos for sale,where engine needs replacing,same with the Toyota Previa/lucidas where the heads gone,the engines slung in underneath the seats.they tend to overheat where the heat builds up around them.
The problem with the Bongo is the cooling system was designed by idiots. Any small leak can cause an airlock which rises to the cylinder head of the engine and causes it to crack when it over heats. Only a few garages know how to bleed the system and as it takes 2 or 3 people about an hour to do anyway most don't want to touch them. I've bled mine a few times now (last week the water pump died and the AA brought me home from holiday) and I spent the whole time cursing the person who came up with the system. The real fun begins when you've got a funnel full of near boiling water in your hand and you have to cap the pipe by removing the funnel without letting any air in to the system and without scalding yourself.
Not to mention there's very little information on fixing problems and parts are hard to get hold of and are often expensive. and they rust everywhere...
I still just spent a happy 2 weeks in mine though (not counting the 2 nights at home fixing the water pump).