1999 V70R Gas cap keeps coming loose

[EAGSMN]

The check engine light is on again with the major evap code and my gas cap is loose every time I go to fill even though I crank it super tight (many clicks) every time I fill up. Same thing happened a couple years ago and I replaced the cap which solved the problem. I am thinking the threads in the filler neck are going bad, is it easy to replace the piece of the filler that the cap screws onto?