A Hole or a Crack?!
 

I was wondering which is easier to TRY to fix on a radiator ...a Hole or a Crack? Now I just went out and bought a new one but just asking out of curiosity :D :D - Allison

Actually the crack is easier if it is in a metal portion of an older radiator tank. The composite plastic radiators are better off replaced. If it is in the cooling area across the radiator, either can be accomplished easily by plugging the area on both sides of the leak. The repairs are better left to a shop that has experience in them. If you have an old one and want to play, go for it.

I actually repaired a large crack in the tank of an S-10 pickup radiator several years ago with a two part putty I bought at Walmart for gas tank and radiator repairs. This was a plastic tank on top of that. I used a grinder and roughed up the surface then kneaded the two parts of the putty together and stuck it all over the crack. I done it for a friend and to my knowledge it is still holding without any leaks. I can't remember what the name of the putty was, but it did work well.