Absolutely! Berryman B-12 Chemtool Fuel System Cleaner (part #0116) is extremely effective in the removal of gum, sludge, and other crankcase deposits, but it should only be applied immediately before an oil and filter change due to the potential overloading of the oil with dissolved sludge and deposits. Please note that if sludge or carbon buildup on worn oil rings has been helping to seal the crankcase, then applying B-12 Chemtool could actually cause the engine to begin smoking even if it didn’t before. Removal of varnish and carbon buildup can also affect tolerances in especially old or dirty engines and cause engine noise (clattering). Removal of excessive deposits can also lead to oil screen plugging and oil starvation. These are very uncommon occurrences, but please be aware of the possibilities. If you would like to use B-12 Chemtool Fuel System Cleaner as an engine flush, pour into your cold crankcase approximately 1½-2 fl. oz. of B-12 Chemtool per quart of oil capacity. If your vehicle holds 5 quarts of oil, then you should use about 7½-10 fl. oz. of B-12 Chemtool. After you’ve added it to your cold engine oil, start the vehicle and run it at idle 10-15 minutes or until the oil is warm. Then change the spent oil and replace the oil filter.