I can tell when the wife's Camry need decarboning and when I had low compression in one cylinder of my Land Cruiser but how do you know when your motor need to be cleaned and how do you know when its done being cleaned? I have Seafoamed via the carb/PCV several different vehicles and have had different amounts of smoke from each one. I assume if you keep Seafoaming over and over it will stop smoking??? Right? What parts in the motor get fouled other than the valves, rings and piston? But when you add to the oil MMO, AutoRX, Seafoam, ect how do you know when it done being cleaned without removing valve cover or oil pan? I bought an abused Land Cruiser with major buildup under the valve cover. Oil Crud buildup More Crud These pic were after one OCI. I did not take pic of the buildup when I first got the vehicle. It had stalagmites on the valve adjusting bolt/nuts. Now how can one say its needs "X" amount of treatments or "X" amount of miles to clear this up? I also had a Chevy 350 with a dead cylinder. It was full of the same crud that was under the Land Cruiser valve cover. Over time I got that cylinder to clean out and work again but it took a long time. Once again, there can be no "X" amount of time to clear it up. My present Land Cruiser has 364,000 mi on it. It has a golden varnish on under the valve cover. Golden Glaze This could take longer or shorter time to remove as its baked on. I could not remove it with my hand unlike the other Land Cruiser build up pic where I could just wipe it off. Other then taking the motor apart is it a guessing game to know when your motor is clean?