After reading about all of these head problems I'd like to understand what actually 
happens (especially before it happens to my '87 Westy)! Can anyone tell me:

What happens inside the engine? It sounds like liquid from the cooling system gets
into the combustion area of the engine. Is the failure always that the head warps
and disturbs the seal with the head gasket or are there other similar failures
with the same effect?

Are the heads defective when they leave the factory and it just takes a certain amount
of mileage for the problem to appear?

If they are defective from the beginning, is there anything you can do in terms of
maintenance or driving style to prevent the problem from showing itself or is it
pre-determined and just a matter of time (mileage)?

Is there a way to detect in advance if the problem will happen? Maybe an oil analysis?

If the problem occurs, what is the correct way to fix it? Do you have to get new
heads? Re-machine the old ones?

After fixing it, what's to say that it won't happen again?

Thanks for putting up with my mechanical ignorance! We're about to make a trip from
North Carolina to the Southwest for four weeks and I'm trying to get everything in order
but I feel pretty helpless about the head thing. Our '87 has 69k miles on it.

Thanks in advance!

Jeff H.