B-12 Chemtool Fuel Treatment can be added to the crankcase immediately before an oil change for removal of gum, sludge, and other deposits. To use as an engine flush, pour into your cold crankcase approximately 1½ oz. of #0116 per quart of oil capacity. For instance, if your vehicle holds 5 quarts of oil, then you would use 7.5 oz. of or about half of one can. After you’ve added it to your cold oil, start the car and run it at idle 10-15 minutes until it’s warmed up. Then change the spent oil and replace the oil filter.