I have a 1991 Ford Ranger 3.0 2wd. It has almost 154000 miles and i opened the hood and the anti freeze tank was empty. I put filled the tank with the antifreeze mix but within a week it had all drained out. I think it it leaking out by the pulleys for the fan but it is not the radiator. Would it be a hole in the water pump?

 

there is a weep hole in the water pump and when the seal goes bad it will leak from there. You need to make sure thats where it is coming from and then replace the water pump.

 

You might also check both heater hoses at the water pump. We replaced heater hoses on my son's 93 ranger today. The previous owner had instelled 5/8" heater hose over a 3/4 " fitting at the water pump and the hose had split underneath the clamp. There was no sign of a leak, other than a small puddle of antifreeze on top of the water pump, and a very thirsty overflow reservoir.