I had an issue with my new grommet fitting loosely in my tank. Did boiling the grommet swell it up for a tighter fit? Also, did you apply the dielectric grease where the tank fits through the grommet’s channel or groove? Thanks!
Boiling the grommet only makes it more pliable (softer) so that it will slip in easier. It does not swell the grommet. If it is loose, you might want to get another grommet. The dielectric grease was applied to the grommet where the filler neck passes through. It allows the neck to slide through easier.