Yes there are fuel tank sealers you can purchase. I have used a few on motorcycle fuel tanks. I have used the one Called "Kreem" and I hate to say it, but is sucks. Every tank I have ever seen coated with it the sealer will peal off within a couple of years. My shop just sent a tank off for sealing not to long ago and it came back with a red sealer in it I believe is "Red-Kote", I kind of like the way it looked. I think it will last a bit longer than the other brand I mentioned. Also, I have also heard a lot of good things by anything made by "POR-15".