Coolant stop leak??

[micksrule]

Depends on where the leak is. If it's a header gasket, where the tank meets the actual radiator, GM used to use kind of a powdered wood. They also come as compressed tablets. Will work great without plugging anything else. Most car manufacturers actually use something like it in all new cars. You should be able to get it at any auto parts store. DO NOT USE BARRS STOP LEAK in any form.

One other thing you can try really cheap is pepper. Don't laugh, I've seen it work.

If it's the actual tank, you'll probably be buying a radiator or at very least the tank.

If the core is leaking, it may be able to be repaired. There's kind of a plastic weld that'll work. Just requires the system be drained below the leak, cleaned and a light duty torch with a light touch.