Some earlier (air cooled maybe) just slip on with a bolt.  My 91 is
pressure fit.  I tried to remove the plastic sleeve from the metal tube
(another van) and I had a VERY hard time getting them to separate (I
had to crush the metal pipe).  It's off and waiting for me to figure out
how to get the plastic part on my van's metal tube.  It has been
mentioned to boil the plastic in water to make it more pliable but I
have no first-hand experience with this.  Malcolm

> I have the dreaded spraying oil problem. It looks like my leak
> (slight) is it the union of the plastic portion of the filler tube and
> the metal portion. How do these go together?