Well, I would have thought that, except that when I ran an application through my Taurus, I got almost no smoke. I treated the Taurus just like the other vehicles, and the other three all smoked to varying degrees. But, I only got a little puff of smoke out of the Taurus. If it was the SeaFoam that was smoking, I would think that the Taurus would also have smoked.
Also, the three "smokers" tended to smoke for several minutes, perhaps as long as 6-10 minutes in some cases. I don't see how a few ounces of SeaFoam could possibly take that long to burn. I believe the SeaFoam is made of volatile organic solvents, such as acetone, toluene, xylene, etc. My understanding of chemistry was never all that great, but I think those materials should burn fairly rapidly and fairly clean.