How much Sea Foam should be added to the fuel in a 2025 Chevrolet 2500 Duramax diesel 6.6 liter? [SOLVED]

Thanks for the question!

For routine/preventative maintenance (keeping an engine clean), add 1 ounce per gallon of fuel.

For a cleaning dosage, here’s what I’d do: wait until the tank is low (1/4 tank), add 2 cans of Sea Foam Motor Treatment, and then drive for at least 10-20 miles before refueling. It’s safe to add a higher concentration like that and it works very well for cleaning residues and deposits.