I use almost a full case of SeaFoam a week. It is a great product, wont hurt anything at all, and will actually help with the fuel mileage in the end. As for the white smoke, its the carbon in the engine that is burning off. Some may have more smoke than others, depending on the mileage and care of the vehicle.
Not really. On my way to Moab the turbo went out on my truck. It only smoked during deceleration, but when it did, it was like I was a mosquito spraying truck. Rather embarrassing actually. I still wheeled the crap out of it at Moab, but for some reason everybody kept insisting that I be the tail gunner. I must be a good tail end Charlie, that's what I keep telling myself.Its hilarious when your driving and leaving a smoke trail like a stunt plane.
i have also wondered about the water treatment. ive heard about it, read about it, wondered about it. it seems like it should work. ive never tried it, but it seems like it should work.12-16 ounces of plain water slowly (should take 1-2 minutes to drain 16 ounces) trickled into the throttle body while the engine runs at a slightly elevated RPM will get rid of any carbon deposits just as easily and a little faster for free. No (!) this does not harm the engine so long as you don't accidentally dump the entire container of water into the engine at once. Water's ability to get rid of carbon deposits was discovered during WWII when it was used in bombers to increase engine power (via water injection) and the mechanics noticed how the engines were sparkling clean internally afterwards.
One thing I would NEVER do with Sea Foam is to pour it into the crankcase, at least not for more than a few minutes before an engine oil drain... which I don't really believe helps anyway.