Is rust in a fuel filler neck a bad thing? I assumed it was. My 3000's restoration was finished about 2 years ago. I noticed my fuel filler neck had rust in it. I ordered a new one and it had rust as well. I ordered a 2nd one from a different company, but turns out it was from the same manufacturer and batch and the first one. ( and probably the one that's in my car now.) I have two fuel filters on my car, and just replaced them, so I think I'm ok. I have plans to cut open the filters and check them.