Tim, Tank flush and then seal is a good way to go. We have saved many a vintage motorcycle tank over the last few years. Never done a car tank so you may have to look at ways to protect the tank outlet and tank vent pipe locations from getting blocked with the sealant.   Ron
30 September 2021 at 1:45 PM #6329
Ron Dowle
Participant

Tim, Tank flush and then seal is a good way to go. We have saved many a vintage motorcycle tank over the last few years. Never done a car tank so you may have to look at ways to protect the tank outlet and tank vent pipe locations from getting blocked with the sealant.   Ron