Thanks! It blew this morning. No one at the parts store knew what it was so they couldn't look it up, and didn't have 3/8" coolant hose anyway. They ended up selling me overflow hose, which I'm not going to leave on there because I assume it's not rated to take actual pressure, but I just needed to complete the circuit so I could test for a HG leak, which fortunately came up negative. Now I know what to ask for when calling around for another one. Thanks again!