Now that I have my gas tank sealed up properly, it is displaying the
old symptoms of sucking itself flat with excessive vacuum.

All sorts of crumpling sounds while driving and a big "whoosh" when
opening the gas cap, accompanied by un-crumpling sounds.

It's only a matter of time before it creases itself and leaks, like
the first gas tank did.

Anyone know what causes the excessive suction?

Could a faulty check-valve on the vacuum line between the engine and
the charcoal filter cause this?  It's about the one thing that I
haven't messed with.

Are there other valves that allow replacement air to enter the
system?  Something should make up for the suction through the vent
lines and the charcoal cannister.

What do the two "gravity valves" on the tops of the expansion tanks
do?  Bentley says that they should activate when turned 180 degrees.
That seems odd, as the only other time that that valve would
experiece such a reversal would be roof down::wheels up.
--

bcnu - Grungy  (Houston, TX)
'60 dddPanel '69 Bug '90 Vanagon '93 Eurovan '00 Audi A6 Avant
grungy@mindless.com           opinions are just that.obviously.