[mechanicalman]

I won't recommend using or not using stop-leak, it is what it is. However,

Envision how large the leak is that you are seeing, in terms of how small the hole or crevice is (a drip every 2 seconds, under system pressure) that needs to be plugged by stopleak. Then, visualize how much stopleak you are putting in there that will be needed to plug that opening and then realize how much of that stuff is in your system left over. Every time you turn it off stuff can settle. Whatever you put in there, stays in there less the very small amount that actually finds it's way to the leak.

So consider then if it does plug your radiator, your engine overheats then you have to fix the radiator AND fix the head gasket. And maybe strands you, etc.

Sure it's not an intake manifold gasket? Freeze plug? Always start from the very uppermost leak and work your way down.