How do stop heater core leaking tercel?

To stop a heater core leak in a Toyota Tercel, you can use a commercial radiator stop leak product, which can help seal minor leaks. Alternatively, you may need to replace the heater core if the leak is significant. Ensure you flush the cooling system to remove any debris before applying a stop leak solution. Always check for any underlying issues that might cause the leak, such as corrosion or loose connections.