The seafoam works best if in the oil and gas as LB has said. I put two cans into my diesel which had lost power was using oil, idled rough and fuel consumption increased to the point I was only getting about 10 miles to the gallon. I put one can into a half full tank and put a whole can into the oil also. Drove it hard while the seafoam was into the fuel and drove it another 2000 klics with it in the oil. Noticed improvement in fuel milage gradually and the idle improved after the first run. Changed the oil after 1500 to 2000 klics on it and now it has improved the fuel mileage where it was before about 18 to 20 mpg the idle smoothed right out and it has not used any oil since before the oil change. I used some in my gas on the Royal Star Venture and it actually kicked out some black soot from the tail pipes. I would not hesitate to put some in the oil in my RX-1 especially with only a couple hundred miles to go before an oil change. I will also be using this for summer storage as well. Now I have not had any oil burning issue I use some but very little. I use amsoil 4 stroke oil and I run the Fitch Fuel Catalyst also. So maybe the fitch is letting the fuel burn cleaner thus preventing the carbon buildup at all. I wonder how many people who run the fitch are having or have not any oil burning issues.