In a message dated 98-04-10 12:47:30 EDT, jgladu@BCM.TMC.EDU writes:

<< A few months ago I had my '90 Vanagon's fuel tank replaced ($650) because
 it had sucked itself into a crumpled and leaky shape.   It just started doing
it again this week - I can hear the tank going "poing" as it deforms inward,
and there's a "whoosh" when I open the gas cap....

Is the cap supposed to be vented? (and it's plugged now?) >>

I don't have the answer to that, but would urge you to buy a vented cap until
you get this sorted out!

gmbulley
cary, nc
Prov.17:22