[s-cars] S4 Moooooing sound

[Dave Burig]

Happy Friday All,
After even a relatively short ride, (10 miles home from work) after parking
my car (93$4) a rather pronounced Mooooooooo comes from the rear of the car.
Open the gas cap, to quote H. Ross Perot, "Giant sucking sound", then the
moo is gone.  Is this common?  Is a breather plugged?  Will my car implode
without notice?
Dave Burig, Cowlumbus, Ohio