seafoam is not to be left in the engine while driveing around. i use seafoam once and a while when changing oil.

drive to my local auto shop and pick up a can and drive back home ( warms engine a bit)

while car is on pour half a can in crankcase

other half goes slowly through a vac line into the intake manifold

after can is empty i shut car off and wait 15 or so min to cool down so i can change the oil.

change oil as you normaly would.