Dayco silicone coolant hoses are used to carry radiator fluids. These hoses have a knitted rayon inner base for better strength and durability, and heavy-duty pressure connections ideal for application in hostile engine environments. Silicone hoses by Dayco meet SAE J20 RL CLASS A standards and are resistant to hardening, cracking, leaks, chemicals and any damage caused by oil, ozone and coolants. These hoses are designed to work in extremely high and low temperatures, with the operating temperatures ranging from -65 to 350 degrees Fahrenheit.