Can I add Seafoam to a full tank of gas? [SOLVED]

Thanks for the question, David. For preventative maintenance, yes, you can add it to a full tank of gas. If you’re using it for cleaning, here’s what I’d do: wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits. Add it to fuel like this every 3,000 miles or once a year.

Hope that helps and let me know if there’s anything else!