It will be safer to replace both the hoses first, before using anything inside the radiator. The liquid stop leak could plug up your heater core, costing lots of money in parts & labor.
Is the liquid stop leak a bronze powder in liquid or a dry powder or a milk or plant derivitive ? A quick call to two or three radiator shops asking their opinion on an internal remedy to pour in the radiator and when & how to do it, might help. Just ask if the person speaking is the one who works on radiators or if you could speak to the one who does.
Even call the local police dept. and find out who does their mechanic/radiator work. Then call and ask the opinion of the mechanic who is their best at fixing radiators.
Hope this helps. Don't forget to check for leaks around / from your water pump & where ever water/antifreeze could escape, not just your radiator.
(PS) I did not get several opinons and did stop up my heater core, and was too cheap to get it fixed till after an Ohio winter. (Who in Canada left the back door open ? Ice inside the car for a long time. Fixed now for sure.
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Edward F Sutton
[This message has been edited by Edward F Sutton (edited July 06, 2001).]