Are you sure that you're supposed to put oil in the weep hole? This is the first time that I've ever heard of this one.

That hole is there to let coolant out if the seal fails. Were it not present, there would be no weep, and thus no coolant loss at all until the seal on the outer bearing failed. Then you're stuck where you are. As it is, the coolant out of the weep hole gives you ample warning that the pump seal is on its way out.

I imagine that oil is not good for the pump seal. If it's noisy, replace the thing. Yes, water pumps are self-lubricating.