You can add Sea Foam Motor Treatment to the oil at any time.
However, we recommend waiting until 100-300 miles before your next oil change to add Sea Foam. Two reasons:
that gives the Sea Foam time to circulate and clean as you drive
that allows all the residues that were reliquefied by the Sea Foam to be drained away with the dirty oil. It is safe and fine to drive for as long as you want with Sea Foam in the oil, but the oil will likely become dirty as the Sea Foam cleans.
You can add Sea Foam Motor Treatment to the oil at any time.
However, we recommend waiting until 100-300 miles before your next oil change to add Sea Foam. Two reasons:
Hope that helps!