Abstract: A composition is disclosed which cleans baked-on, carbonized sludges and varnish deposits from the internal surfaces of automobile, motorcycle and truck engines. The product comprises a mutually synergistic solution of selected cyclic compounds, aliphatic amines and water, preferably dissolved in a hydrocarbon or hydrocarbon and aliphatic lower alcohol fuel base. The solution or base product may be placed in a pressure resistant (aerosol) dispenser, and pressurized. When injected into an engine over a period of time, significant removal of deposited contaminants occurs, resulting in smooth and efficient engine operation and lower levels of unburned hydrocarbon fuel, carbon monoxide, and other air pollutants.

Abstract: A formulated composition is disclosed which is designed to clean baked-on, carbonized sludges and varnish deposits from the upper cylinder surfaces of automobile, motorcycle and truck engines. The product is comprised of a mutually synergistic solution of selected cyclic compounds, aliphatic amines and water, preferably dissolved in a hydrocarbon or hydrocarbon and aliphatic lower alcohol fuel base, to which minor materials may optionally be added. The solution or base product may be placed in a pressure resistant (aerosol) container pressurized with a compressed gas, such as nitrogen gas. A preferred embodiment of the invention utilizes a synergistic solution of N-methyl-2-pyrrolidone, n.butylamine and de-ionized water, with these ingredients present at certain ratios. This solution is dissolved in either mixed iso-(C.sub.7, C.sub.8)-hydrocarbons or a combination of such hydrocarbons with a minor amount of isopropanol, to which up to about 10% by weight of other optional ingredients may be added.