How do you repair the plastic piping on the radiator that the upper hose clamps onto?

How do you repair the plastic piping on the radiator that the upper hose clamps onto?
JB Weld? Drain fluid, make sure it's realllly dry. If it's cracked, smear JB weld or another epoxy compound that bonds to plastic, wait for it to cure (probably 4-6 hours), then refill fluid and see if it leaks at full operating temperature.