This may sound like a stupid question and I am a bit embarrassed to ask but does anyone know what the barbed connectors are made of that join the upper and lower sections of the heater hoses on the 03 5.7l Ram trucks. I am getting ready to do a coolant system flush and gathering all the parts to also replace all the hoses as they are all factory original and 17 years old. No one sells the complete assembly anymore so I have to get the molded upper lines and 2 90 deg bend lowers where it connects to the engine and there are couplers there. I dont know if HOAT will react with certain materials. I have found Aluminium, brass and plastic but I can not tell whats in there until I disassemble and would like to have replacements handy mostly incase they are plastic and break while trying to get the hoses off.