which is exactly what tank Seafroam treatment is doing, just slower and over time. And through crankcase, it cleans everything where oil goes, which is piston rings, valves, etc. I prime all of our cars with Seafoam at least once a year.
I agree with the seafoam method, however it does not run through the injectors to clean them out. Some systems actually disable the fuel system and the engine runs entirely on the cleaner.
ha-ha. good observation. if you ever tried to start an engine after Seafoam poured directly into combustion chambers, that is absolute truth. White cloud sky high for about 5 minutes. Surprisingly, starts fine, maybe just a bit of hesitation initially.
I've never poured it directly into the cylinders, but have sucked it through a vacuum line many times, and have always been dumbfounded by how long the vehicle will smoke. If a guy was inclined to be ornery (as obviously NONE of us are!) you could REALLY screw with somebody's head, by doing that on their car without them knowing it! I've got one brother-in-law with OCD that, if I did that to him, he'd probably end up in the Psyche Ward.