Liqui Moly's Hydraulic Lifter Additive damps the noise produced by worn hydraulic lifters. Cleans valves and holes in the lifter and promotes optimum operation. Add to engine oil, for all gasoline and diesel engines with and without turbo-charging. Tested for compatibility with catalytic converters. Liquid Moly's Hydraulic Lifter Additive can be mixed with all commercially available engine oils. 300 ml is sufficient for up to 6 liters (6.34 quarts) of engine oil.