Fuel nozzles cleverly detect the sudden rush of air up the filler pipe
that happens as gas gets up to the top of the tank and shut themselves
off.  Really slow filling can fool this system, as can having the nozzle
too far out of the filler neck, but I don't think an air leak in the
tank would.  My '84 does not pressurize the tank, I don't think any
Vanagon does.

The only way to fix a leak would be to drop the tank and check the hoses
and tank condition.
--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext. 8208
Fax: 206-269-6360

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