well you left out the most important piece of information, what color is the fluid? and do you have anti freeze in your radiator? if its just water in there its most likely your radiator is still leaking if its the same color. if its red its transmission fluid in which case you need to go to a mechanic. power steering is kind of ambiguous it might be red/pink/amber clear.. are you fighting your steering wheel to turn?
stop leak is horrible, think about it... if it glues that shit in your radiator shut it will clog up your hoses and other shit it gets into too...
if your radiator is just water in there this is what id do
look under your car where the hose for the radiator is, make sure its not a busted hose. if you dont see any hoses leaking do this, if not replace the hose: buy a couple jugs of 50/50 radiator fluid from shucks or autozone, theyre usually 2 for 9$$. unhook the hose and drain out the water in your radiator completely. hook the hose back up and make sure its snug, or has a clamp clamping it tightly on there. fill radiator with the 50/50 mixture, make surey our overflow is filled to the line. go to the dollar store and buy a 1$ can of "ground black pepper", make sure its "ground black pepper". dump half the can in your radiator and run your car for awhile. the pepper will find the leak and get stuck there, and crust itself over the leak. the pepper wont clog up other shit and cause other leaks elsewhere like the stopleak will. the peperi s the same thing as the aluminum powder or titanium powder shit they sell you for twenty times the price.
i had this problem in the summer, there was a penny size hole in my raditor near where the radiator fan was, and i did the pepper and it crusted over the hole and i haevnt had a leak since. you can drive around for months like this, but if this stops the leak, you figured out your problem and should eventually replace the radiator. oh yeah and DONT EVER OPEN TAKE THE CAP OFF YOUR RADIATOR WHEN ITS HOT!!!! its like opening a soda you shook up times twenty, youll have boiling hot radiator fluid shooting at you and all over your engine like old faithful. if this doesnt solve the problem you need to isolate where the leak is coming from. get on your back and get under there and get dirty if you want to save money... its pretty obvious if its coming from the water pump or the radator.. google what a water pump for your car looks like and see if its leaking from there as well, and if it is get a knowledgable friend or mechanic to replace it
what i thikn happened was the stop leak stopped your leak in the raditor, but clogged up one of your hoses, and if your hoses were old they couldnt handle the extra pressure of it pumping through a clogged hose and it burst the hose somewhere and you need to replace a hose somewhere, isolate the leak
