Gates molded coolant hoses are designed using EPDM material for superior electrochemical resistance, so your Gates coolant hoses will last longer and keep your engine systems running stronger. An electrochemical degradation or ECD occurs when the hose, liquid coolant, and engine/radiator fittings form a galvanic cell or battery, creating a chemical reaction that allows micro-cracks to form in the hose tube. Coolant seeps into these cracks or striations and breaks down the reinforcement, leading to hose failure and, ultimately, roadside breakdowns. Gates radiator hoses are manufactured to fit upper, lower, bypass, heater and other coolant applications with OEM-quality specifications, saving you time, costs, and energy from going to your OE dealer for radiator hose replacements.