Don't use stop leak! A lot of that stuff on the market clogs up your cooling system, especially your heater core! (aren't those fun to fix
) Anything stopleak is bad for your car whether its P/*, transmission, and A/C. I won't do A/C service to a car with stop leak in the refrigerant because it clogs the filter for the A/C machine and it won't work(older) new ones won't even let you service the car. The only coolant stop leak I have had be ok is the GM brown tabs that you smash with a hammer. If your gonna replace the radiator just keep topping it off, its your best bet.