How can you Fixed radiator leaking?

There are radiator sealants available at many auto parts stores. I personally have never been able to get them to work though another good way to seal a leak if it is on the aluminum part of the radiator is to solder it with silver solder.

However, in general the only real solution is a new radiator.

if your in a bind and your desperate and just so happen to have eggs available keep in mind that you can throw a couple of them in your radiator when its still warm and the eggs will cook and when they do they will fill the cracks a little so you can limp it somewhere, no racing.. hope this helps... oh ya do this while its running for those of you with less common sense than us other people