Multi-phase suspension coolant

A polymer encapsulated solid-liquid or a solid-solid phase change material for use in a fluid coolant heat exchange system is disclosed. The resulting coolant has a higher heat transfer rate than a conventional fluid due to the utilization of the heat of fusion of the material. Thus provided, the improved coolant will allow down sizing of the coolant pump and subsequent reduction of parasitic loading. Engine heat up time can be increased due to the lower coolant flow rate and heat transfer capability at below operating range temperatures.