For internal engine cleaning. Dissolves old deposits and dirt. Effective against oil sludge. Particularly useful for removing deposits that can build up in e.g. valve tappets or oil ducts. Can be used in e.g. old engines that have not had an oil change in a long time. For use during oil changing and results in a clean, well-functioning engine. Can be used in both petrol and diesel engines. Also suitable for flushing hydraulic systems.