Resin helps keep engine-coolant heater running

May 22, 2003

Engineers at engine-preheater maker Kim Hotstart Manufacturing, Spokane, Wash. (, used Amodel FR-4133 polyphthalamide (PPA) for the firm's tank-style engine-coolant heater. The material is part of a new generation of flame-retardant PPA resins from Solvay Advanced Polymers LLC, Auburn Hills, Mich. ( A cover and end cap, injection-molded from the FR-4133 resin, enclose the heater's electrical components. According to Joe Gaylord, the product's design engineer, "We can use water-cooled molds for this part with much lower temperatures, which reduces mold maintenance, relative to the oil-cooled process required by the PPS material we use for a similar product. The Amodel resin has similar properties to the PPS, but there are cost and processing advantages."

The material has a heat-deflection temperature of 574°F, and withstands the 180°F coolant temperature it sees during preheating or when the engine is running. Also, it quickly crystallizes in water-cooled molds, allowing for fast cycle times using molds as low as 150°F.

The engine-coolant heater sees action on small, water-cooled reciprocating engines, up to four cylinders and 2.5 liters in displacement, used on small construction or excavation equipment working in cold temperatures.

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