>rear-ending of White Wing II (86 vanagon) The water tube from the 
>pump to the thermostat housing was jarred heavily. The rust that I 
>thought was surface was foun to be internal and through the steel. It 

Mine was like this, no accident. I heard a slight hiss every few secs after 
getting out of the van late night, coming from the rear. This pipe was 
pinholed and dripping onto the exhaust where it hissed.  Never dripped to 
the ground, very sneaky leak.  Took off the pipe, sandblasted til bare then 
brazed over every hole/pit on the thing, fine so far, will likely snap off 
completely when I'm floundering in the woods miles from help.  Tim Smith