Re: 99 Ford Ranger 3.0 Ex. Cab
If your not over heating and the gauge is in the normal area all the time, no milky color in the oil, I think you fine with the cooling system. To your question above, if your coolant is leaking out of the over flow container it could be caused when you filled the radiator by over filling it when you replaced the water pump. You can buy a pressure tester at any auto part store. Easy to use.
2003 Ford Ranger 4 Door 4x4 FX4 4.0L
2015 Ford Focus