Abstract: A cooling system for a molding tool or molding machine includes a high-performance coolant, multiple cooling circuits with different coolants flowing along each circuit, and/or a self-contained cooling circuit. The high-performance coolant can include a metallic component in various forms, including a liquid phase metal form. Newly recognized coolant characteristics such as volumetric heat capacity (Cv) can be used to identify suitable coolants. High-performance coolants can be used to reduce molding process cycle times, to spatially equalize the cooling rate of the molding material among different sections of the mold cavity, and/or to help cool other parts of the tool or machine such as a runner or an injection sleeve.