Anyone ever flush their engine to clean it out? I know you can get stuff like STP engine flush and others, but they are basically kerosene/diesel fuel. You can buy that at the gas station for alot less when it's not labelled as engine flush. See the bottom of this link for the main ingredient of engine flush: http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=16004096 and also for carb cleaner: http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=3007075 I have heard from mechanics that you can drain your crankcase, change oil filter, add 2 qts diesel, 3 qts cheap oil, run for 10 min at idle (no load), and drain. Repeat. Third time change filter and add 5qts oil and your engine is flushed. What about using 30SAE (which is usually a high detergent oil) to clean out your engine? Run SAE30weight for a day or two and then change oil as normal? Any negative effects of running straight 30wt oil?