Yes it does but its not a majic fix in a bottle. It is ment to clean out the oil and carbon deposits in the intake and on the valves pistons and combustion chamber went ran SLOWLY through the intake manifold. It also helps clean injectors when added into the fuel. I would NOT add it into the oil to clean sludge from the engine since putting a slovent into the oiling system is a very bad idea. It will brake down the oil and there is no way you are getting it all out just by drain the oil and changing the filter, it would take several oil changes to remove all the seam foam from the oil. So think about it you have a small amount if strong solvent in your oil for 10k plus miles, not good imo. Valvoline makes a great engine flush that works very well and does not contain any solvents.
