It should work assuming the leak isn't too big. Try it you have nothing to loose.
There really is no way except to replace the core. In the old days you could pull the core and have it soldered up at a radiator shop, but most modern heater cores are aluminum and plastic. You can try stop leak but i have had very poor results using stop leak in heater cores.
Replace the line that is leaking, and do not try any stop leak.
use leak stop or something. Where is your oil leak?
You need to find the leak to be able to stop it. Check all of the hoses and the engine around the gaskets, as well as the heater core to find the leak.
Most stop leak additives do nothing but empty your wallet. Replace the gasket that is leaking.
If coolant is leaking inside your cabin, you have a leak in the heater core. The only repair is to replace the heater core. Most auto parts stores sell them.
The only way to fix it is to replace it and check the head at a machone shop. You only patch an engine to get you home or to a shop to get it repaired. Stop leak may damage radiators,thermostats and heater cores.
your heater core is leaking coolant Uh oh. DO NOT USE "stop leak". Just replace the heater core. It will cost ~$500US to get a mechanic to do it, or $20 for the core and 20 hours of your own time if you do it yourself.
Be careful - some of these products can plug the heater core
caused by leaking heater core not radiator heater it is under the dash hard ot get to if the leak is not to big use radiator stop leak otherwise fix is going to be big bucks