[BRENT in 10-uh-C]

Before you go there, why not place some Stop-Leak into the cooling system?

I also add a small rubber hose to the overflow tube and crimp it so the system will build a slight amount of pressure as it warms up (i.e.: 2 - 3 lbs) which will generally force the stop-leak out of any weeping holes. Then drain and allow to dry overnight. Then refill with coolant & water and see if your problem is not solved.