No, it won't stop the leak. I think the leak is coming from the head and coolant is seeping down to where you see it, on the collector. You'll probably have to take the bolts off from the collector and take the manifold off. Could be a cracked head is the worst thing.

First thing, how long was the car running till you noticed it smoking? It didn't do it before, that you know of? You changed the fuel pump and this just started? Then read previous comment