RTV is far from the ideal sealant for a crack on a radiator. RTV has no stregnth to keep the crack from spreading. The pressure and vibes will eventually make it fail again. The crack will get bigger than your seal job untill it goes all the way around the "nipple" and the thing breaks into gushing catastrophic firehose mode. Your nice piece of radiator "nipple" and gobs of RTV will still be clamped inside the end of the hose.


Get it soldered ASAP. That will keep it together for a while. Solder isn't ideal either but its better than RTV. Budget for a new radiator soon.

 

None of the shops around here said that saudering was an option. They said they could only replace the entire radiator. The truck won't be getting much use past august so I will put the gas money away and if a radiator is needed, I will be secure.